Category: Coffee review

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Coffee review Observations slow Tea

Coffee prints at Water Lane Brasserie, Canterbury

coffee in a friendly environment Canterbury
Drinks at Water Lane Brasserie, Canterbury

Making our way down the cobbled High St in Canterbury, into a side street within the old walled town and then following the black board signs for coffee, we found our way to Water Lane Brasserie on Water Lane. Although it is very close to the High St and even the bus station, somehow Water Lane Coffee feels quite hidden. We had decided to try Water Lane for a spot of lunch as we had read good things about the food and coffee. A friendly dog welcomed us into the café where a few groups of people were chatting or working on their laptops.

Various, slightly out of place, ornaments were dotted around the fairly large space. There was the Newton’s cradle in the window, the Fly agaric mushrooms near the sofa seats, the hand grinder and syphon brewer near the counter and, of course, the jenga sets on some of the tables. As various customers came and left, the friendly service suggested that this was a café in which relationships are built along with jenga towers. Corny analogies aside, it may have been tempting to focus a café-physics review on such pieces dotted around. However, it always seems that the more that you contemplate a place, the more rewarding the observations become (to yourself at least, whether they become more interesting to others is quite another matter).

mushrooms at water lane
A Fly agaric (Amanita muscaria) mushroom near the sofas. Learning about how to identify mushrooms is excellent training in noticing.

Our soup, which was indeed a lovely way to enjoy a light lunch meant that we had quite some time to look around the café. Just outside the window, a bird feeding area with hanging bird feeders had somehow attracted an ingenious moorhen that was cleverly balancing on a conveniently placed pole while grabbing food perhaps intended for smaller birds. Inside, punting equipment lined the walls as it seems that you can punt in Canterbury’s river now when it is warmer (is this a new thing? I cannot remember this from years ago when I used to be in Canterbury more regularly). On a shelf above the counter there were several beers with the logo “Canterbury Ales”.

By this time we were enjoying our coffee (long black) and soy hot chocolate. These were a great finish to the soup. Although there was no information about the roaster, the coffee was very drinkable, darker rather than fruity. As we moved the soup away, the indentations on the top of the (old card table) table became more obvious. Rather like footprints in the sand or fossils in London’s Portland stone. Evidence on a table top of coffee-drinkers-past. Could we gain much information from the imprints left on the table top? Firstly, this table has not just been used for playing cards, a fair few plates of food have been placed on it. Secondly, some very heavy small objects, given the shape of the footprint, perhaps vases, have also been put on the table in the past, was this used decoratively? It is difficult to know with any certainty what happened on this table but with a bit of extra information, such fossil footprints can be full of information.

coffee prints at Water Lane
The table top at Water Lane. What can you discern from the indentations that have been left?

When thinking about fossil footprints, as with the table, the first bit of information that can be gleaned from the fossil is the size of the animal (or object) that made them. So even in the absence of a skeleton fossil, it would be known that some dinosaurs were enormous. Last year a set of dinosaur footprints were discovered in Australia that were 1.7m large, a single foot larger than many humans are tall. Then there is the information that can be ascertained from multiple footprints, such as the idea that perhaps dinosaurs hunted in packs or at least, that some dinosaurs such as the Tyrannosaurus Rex moved in small groups, presumably for hunting. Elsewhere, the presence of different types of dinosaur footprints that seemed to move in different patterns suggested a hunt that occurred millions of years ago.

Tristan Gooley in “The Walker’s Guide to Outdoor Clues and Signs” suggests using more recent footprints to see the wildlife stories that have recently unfolded around you when you walk in the country*. He writes:

“Tracking is built upon these simple, logical principles. All four-legged animals lift and replace their feet in a set order and rhythm and this reflects their evolutionary heritage….. It will not be long before you come across two sets of tracks that are clearly related in some way. The two types of tracks, their character, the spaces between them, the habitat, the time of year and a host of other circumstantial evidence will reveal whether an animal was hunting another, scaring it off, playing with it or trying to mate with it. Here, following the track means reading the story.”

Returning from our day dreams and to the table at Water Lane, looking out the window it became apparent that a figure was staring back at us. Standing just on the other side of the river Stour, a short, stout, statue of a monk looked out from under the hedge around the church beyond the river. The old Greyfriars chapel dates from the thirteenth century, the home of the (then recently formed) Franciscans, named after St Francis of Assisi. Details of the history of this place are revealed in old graffiti around the venue. The monk on the river seemed to silently acknowledge the place’s history as the water ran by. What clues as to previous visitors are there in this friendly, quiet and contemplative café on the river Stour? What will be our imprint on the world when we leave it, as individuals, as a society?

Water Lane Brasserie is in Water Lane, Canterbury.

“The Walker’s Guide to Outdoor Clues and Signs” by Tristan Gooley, Hodder & Stoughton, 2014

*Not just the country. In many urban parks you can see the recent behaviour of geese, sea gulls and the dogs that chase them, or walking down a pavement tracking a dog that has just walked through a puddle. Hearing a story from the clues left behind needn’t just be a game left to country walkers and fossil hunters.

 

Categories
Coffee review Coffee Roasters General Observations slow Sustainability/environmental

Seeing the light at Redemption Roasters

Coffee Bloomsbury
Redemption Roasters Cafe on Lamb’s Conduit St.

At the top end of Lamb’s Conduit Street there is an unassuming café in a fairly modern building at the corner of Long Yard. In recent weeks I had been hearing a lot about Redemption Roasters and their café. First came the review by Double Skinny Macchiato, then various comments on Twitter, in Caffeine magazine and finally, an article in the FT. In an ideal world, it seems to me that cafés can act as seeds towards forming a better society. Local and independent, a friendly place where you can chat with the baristas (or café owners), and so where communities can form and develop. All that I had heard about Redemption Roasters café fitted, in some way, into this ideal which meant that it was not going to be long before I headed towards Bloomsbury and tried this new café.

Plenty of seating could be found inside the café, with tables of two or four and benches around the space. The counter was immediately in front of us as we went through the door and the friendly barista took our order (long black and soya hot chocolate, what else?) while we took our seats. There were a fair few staff in the café when we visited, so many in fact that we weren’t initially sure who were staff and who were customers. Nonetheless, their joviality transformed the café’s fairly austere decor more into the feel of the welcoming space of a living room.

blue shadow, hot chocolate
A layered hot chocolate? No, just the reflection of the saucer in the glass.

Having taken our seats and started to look around, we found that much could be said about the science in this café. From the SMEG refrigerator and individual radiators to the light reflection off individual sugar crystals in a glass on the table. Moreover, when our drinks arrived, the reflection of the (blue) saucer in the hot chocolate glass made it appear as if the hot chocolate were layered. In fact it was an optical illusion caused by the way our minds process the colour blue in shadows, more on that in this great article about colour, Goethe and Turner. But it was to a different lighting effect that my thought train eventually turned. Above the counter are a series of hanging lights with angular shades over them. Above our table were LED bulbs inset into the ceiling.

The way that the LEDs above us had been placed produced two shadows from the spoon on the saucer of my cup. A dark shadow and a light shadow at a slightly different angle. One reason that LEDs have caught on as a light source is that they are more efficient and so better environmentally and cheaper financially. So you may think that LEDs are one way of reducing our (collective) environmental footprint. But does this work? According to a study that measured the outdoor light levels around the world from 2012 to 2016, the answer is no. It would appear that while on a local level, people are enjoying cheaper lighting, on larger scales (nationally, globally), this decreased cost is leading to us installing more lights. Consequently, on the global scale, the area of land that is lit has increased by 2.2% per year with very few countries showing a reduction or even a stabilisation of the amount of outdoor areas that are lit.

shadows from a coffee Redemption Roasters
Determining a presence by noticing an absence. The two shadows of the spoon came from the light bulbs inset into the ceiling.

Does this matter? Well, it is something that is affecting us, the way we view our world and the wildlife that we share our planet with and so it is something that we ought to be thinking about. In brightly lit areas of the UK, trees have been shown to produce buds up to 7.5 days earlier than in darker areas. Artificial light is causing problems for nocturnal insects and animals, with knock on effects for crop pollination. And when was the last time you looked up at the sky on a clear night and saw seven of the Pleiades let alone the Milky Way? How does it change our psychology and philosophical outlook when we can no longer gaze at the night sky with wonder and without the glow of streetlights?

Some astronomers have called for increased shielding of street lighting as a way for us to both enjoy well lit streets and be able to enjoy looking up at the night sky. Shielding such as that over the lights over the counter at Redemption Roasters café, where the light is efficiently directed downwards rather than be allowed to escape into the sky. Small steps that can make a big difference. It is interesting to notice that around central London at least, many newer lampposts are more efficiently shielded than older ones. Pausing for a coffee in Redemption Roasters café is a great moment to consider this problem and your reaction to it. Have you stopped to gaze at the night sky recently?

After leaving the café, I realised I had lost an opportunity to notice something else. Frequently, after visiting a good café, I will look up the area in my London Encyclopaedia¹ to see whether there is anything of interest historically in the area of the café. As expected, Lamb’s Conduit St was named after a conduit made from a tributary of the river Fleet restored by one William Lamb in 1577. But Lamb also donated 120 buckets for poor women of the area to use for collecting their water, which explains the statue of a woman with an urn at the top of the street. However what was also mentioned was that at the entrance to Long Yard (ie. very close to Redemption Roasters) there is an ancient stone inset into a wall with a description about the Lamb’s Conduit. Somehow I missed this though Double Skinny Macchiato evidently found it. So if you do visit Redemption Roasters café, and I would very much recommend that you do, as well as taking some time to savour the coffee and to notice the surroundings, please do look out for this elusive stone and if you find it, do let me know.

¹The London Encyclopaedia, Weinreb, Hibbert, Keay and Keay, MacMillan, 2008

Redemption Roasters Cafe is at 84 Lamb’s Conduit St, WC1N 3LR

Categories
Coffee review Observations Science history

Hidden appearances at HoM

hot chocolate, soya, marsh mallow, HoM
Hot chocolate with marshmallows at HOM, Kings Cross.

In these long dark afternoons in the northern hemisphere, what could be better than a warming mug of lovely coffee in a bright environment? And so it was that we ended up at House of Morocco (HoM) on the Caledonian Road. Alerted by Brian’s Coffee Spot that Pattern Coffee had changed hands and become HoM we headed up to Kings Cross one damp afternoon in December to see how things had changed. Entering HoM is a strange mix of déjà-vu mixed with new. The pattern on the wall next to the window remains, as does the layout of the place. However it is also clear that much has changed since HoM took over.

There are murals and variously coloured cushions dotted around the café. Even in the darkness of the afternoon, the café was bright, but also crowded. We ordered a soya hot chocolate, a long black and a cheesecake and found a seat perched at a small table for two near the door (the only seat left at the time). The coffee, roasted by Terrone Coffee, was nicely balanced for the afternoon. But it seems that the hot chocolate and cheesecake combination were a real hit. The cheesecake was apparently very good (definitely worth a return visit apparently) while the hot chocolate went very quickly!

Inside the café, the windows were steaming up with the warmth of the inside. We over-heard that this was because of the coffee machine rather than any extra heating that had been installed. Does this suggest an alternative energy source? Coffee machine heaters to go with treadmill electricity generators in gyms?

all about pigmentation at HOM
Menu with sugar bowl and glazed tile at HOM, Kings Cross.

Meanwhile, the decoration was demanding my attention. A vividly coloured glazed tile supported a jar of sugar which was propping up a black and white menu. The menu had an illustration reminiscent of henna tattoos while above all of this balanced a peacock feather in a vase. Underneath the peacock feather was a poster advertising the “Phantom of the Opera”. The whole ensemble was suggestive of appearances and how they can be deceptive. The phantom of course wore a mask to disguise his disfigured face. But the peacock? The peacock is hiding something too.

Many of the colours that we see around us such as those making our coffee brown and making the tiles colourful are as a result of energy from the light being absorbed by the atoms in the substance (the coffee or the tile). This type of light absorption (and emission) can be connected with vortices in coffee as was discussed here. However the blues and greens in a peacock feather are different. If you look at the feather under a high powered microscope, you will find that the feathers are not dyed as such, in fact the natural colour of the feathers is quite dull. Made from keratin (as you can find in your fingernails) and melanin (responsible for the brown pigmentation of your skin, eyes and hair), the feathers do not seem blue at all. In fact it is the structure in the feather that is producing the colour rather than any dye that produces the colouration.

It turns out that there is a long history concerning our understanding of the colours of a peacock’s feather. It started with Robert Hooke who, in 1665 described the feathers of both peacocks and ducks and noticed that the colours he saw under an optical microscope were ‘destroyed’ by putting a drop of water on the feather. A little bit later and Isaac Newton was suggesting that the colouration was due to the thickness of the transparent bits of the feather. There’s a link here to coffee. Newton was suggesting that an effect similar to thin film interference (which causes the rainbow colours on the bubbles in a coffee) was causing the colours of the peacock feather.

appearances at HoM
Peacock feather and phantom poster with the top of a mirror. How does structure affect what is seen?

As our understanding developed through the centuries (and the microscopes became more powerful), it became apparent that while thin film interference (and multiple film interference) could cause some animals to appear as if they had certain colours, the peacock, along with some other animals, was a little bit more special. Rather than just being the result of reflection off an interface, the peacock’s feathers showed structure at the nanoscale (1/1000000 of a mm). The keratin and melanin in the feathers were arranged in a square lattice to form what is known as a ‘photonic’ crystal. The way this structure reacted with incoming light meant that only certain wavelengths were reflected from it. Depending on the size of the layering in the feathers, they appeared as blue, green or yellow.

Although a lot more is now understood about the factors, structural and chemical, that lead to colouration in all sorts of creature, be they butterflies or beetles, peacocks or pigeons, there is still more to discover, more to understand. The authors of the paper referenced here wrote

“In this paper, we describe a wide variety of structural colors occurring in nature and attempt to clarify their underlying physics, although many of them are not fully clarified.”

There’s clearly a lot more work to do before we can properly explain these “beautiful microstructures”.  And plenty of time to do so as we sit enjoying well made coffee and hot chocolate in a bright and warming café.

HOM can be found at 82 Caledonian Road, N1 9DN

 

Categories
Allergy friendly Coffee review Coffee Roasters General Observations

Focussing the sound at Spike and Earl

soya latte ginger beer
Soya latte and a ginger beer at Spike and Earl.

A few months ago, news came that the coffee roasting company Old Spike had opened a new café, Spike and Earl, down in Camberwell. Operating on similar principles to Old Spike, Spike and Earl aims to serve excellent coffee (and food and cocktails) with a social conscience. By employing those who have previously been homeless, Spike and Earl offers an employment (and training) route for people who may not easily otherwise have the opportunity. So although Camberwell is a bit of a trek, I was looking forward to trying this new place. As it was a late afternoon in November and the menu suggested that the dairy alternatives were only soya or oat, I decided to try a soya latte. (For any reader with a nut allergy, the current fashion of using almond milk means that you should always ask first if your cappuccino contains nuts). The baristas were friendly and confident in assuring me that they do not use almond milk (no danger of nut-cross contamination) but that their brownies did contain nuts (so I sadly had to pass on the brownie opportunity). My partner in these café reviews opted for a ginger beer.

There were a series of high tables with stools on the left hand side of the café. Presumably many people can therefore be accommodated when it gets crowded. However, at the time of our visit, it was fairly empty and we made our way to the rear of the café. Behind us, and behind closed glass doors, was a coffee roaster that we later discovered was part of the Old Spike roasting expansion. It’s always a nice touch to see coffee roasting happening as you drink but perhaps we needed to arrive earlier for that.

Bricks with holes Spike and Earl
Holes in bricks at Spike and Earl. Just a foot-hold or a suggestion for a great piece of engineering?

Drinks arrived together with complementary water and the soya latte was very smooth. Almost caramel like in the sweetness and very drinkable. It makes a pleasant change to have a latte once in a while. Light was playing tricks around the room as the sun was setting and the inside lights were becoming more prominent. But the striking thing about Spike and Earl was that the bricks used to support the tables and line the walls all had holes in them. On the wall running along the side of the café, (windows were on the other side), pot plants were placed in the holes giving the impression of the beginnings of a green wall. The holes in the bricks supporting the table meanwhile made an excellent footstool and were complemented by holes in the stools. A latte of course is largely made up of holes, or at least bubbles. The foam structure consisting mostly of air. How is it that some structures can be made better owing to what they don’t contain rather than what they do?

For example, if you imagine the difference between a latte and a cappuccino (but made out of metal rather than milk) that can be the difference between a successful tooth implant and a failure. We know from our coffees that bubble size can have a significant structural effect. But how about more fundamental properties, can the holes in bricks change things such as the way sound propagates?

Interior wall at Spike and Earl
More bricks with holes at Spike and Earl, this time with some plants escaping from them. The start of a green wall?

You may have heard about how different structures can be engineered to make materials “invisible” to certain frequencies of light. Imaginatively named “invisibility cloaks” are made by designing materials with patterns on them that change the path of an incident light beam. Because the effect on the light beam is due to the structure in the material rather than purely from the material itself, these materials have become known as ‘meta-materials’. When you remember that microwaves are a form of light, it is perhaps easy to see some of the applications of this research and one reason that it has attracted a lot of funding.

However there is an acoustic type of metamaterial that is far more similar to the bricks in Spike and Earl and that may find applications in medical imaging (ultrasound). Earlier in 2017, a team from the universities of Sussex and Bristol published a study about acoustic metamaterial ‘bricks’. Each brick had a differently shaped hole through the centre of it which delayed the incident sound wave by a specific phase interval (you can say it ‘slowed’ the wave). In order to work efficiently, the brick had to be of a height equal to the wavelength that the researchers were interested in and a width equal to half that wavelength. As they were investigating ultrasound, the bricks were therefore about 4.3mm square and 8.66 mm high.

By assembling the bricks together, the researchers found that they could steer a focussed beam of sound or even change the shape of the sound beam. This would have applications as diverse as targeting cancer cells with ultrasound to levitating a polystyrene bead. You can read more about their research here (or, if you have access to Nature Communications, their paper can be downloaded here).

soya latte Spike and Earl
Layering at the end of my soya latte. What would you think about?

Just for fun, assuming that the bricks supporting the table at Spike and Earl could be similarly turned into acoustic metamaterials, we could calculate the musical note that they would best work with. Estimating the brick at about 15cm square and remembering that is approximately  half the wavelength (λ/2) and using the speed of sound in air to be 330 m/s, we can calculate the frequency to be:

f = c/λ

f = 330/0.3 = 1100 Hz

Which is the musical note C#6 (with an explanation of nomenclature here).

As I finished my soya latte, strata of milk lined the cup. Reminiscent of the Earth’s layers or perhaps, metaphorically, our strata of understanding, there is certainly plenty more to ponder at this interesting new(ish) addition to the London café scene. So next time you are in Spike and Earl, do let me know what you end up thinking about, you never know where these thought trains may take you.

Spike and Earl is at 31 Peckham Road, SE1 8UB

 

Categories
Coffee review General slow Tea

Data overload at The Gentlemen Baristas

coffee Borough
The Gentlemen Baristas in Borough.

Borough is always such a great place to wander. Walking around the backstreets with their bits of hidden history. The other day, we had visited the market, wandered down Redcross Way past the old Crossbones graveyard and hit upon The Gentlemen Baristas on Union Street. It is difficult not to have heard about these Gentlemen and my visit there was long overdue and so, we wandered in to try this famous venue.

The shop front advertised itself as a “Coffee House”. A very accurate description and a nod to the Coffee Houses of the past. As it was shortly after lunchtime, it was very crowded with a diverse bunch of people and felt a little cramped at the counter. Nonetheless, the queue was quick and friendly baristas soon took our order allowing us to retire inside to try to find a table (no chance) or a stool next to a bar (successful). Around us, people were either chatting over their coffees or working on laptops.

While waiting for my long black (intriguingly described on their website as a “well mannered coffee”), I noted the various posters describing different types of screw head or parts of the human skeleton. Enough detail to be a phone distraction but surely there was more physics waiting to be seen in this convivial back room of a coffee house? A blackboard at the end of the bar, offered details of the wifi as well as a quote (slightly adapted) from PG Wodehouse about the benefits to friendship of a shared taste in coffee. On a shelf opposite the blackboard were a number of books including a thick book detailing coffee trading in years gone by. From the fact that the books were stacked horizontally, it would appear that they are not consulted often.

shelf books hats Borough
The lighting made photography difficult but you can see the books (and the hats) on this shelf at The Gentlemen Baristas

Sitting between this juxtaposition of wifi information and old books, caused me to pause. I have heard it said that we “know” more now than we have ever known in the past. That we have access to an enormous amount of knowledge merely through our phones. Is this correct?

On one level it is certainly un-arguable. Ninety percent of the world’s data in 2013 had been generated in the previous two years. If you need to find anything out, a quick duckduckgo (or if you have to, a google) will often lead to websites detailing all sorts of quirky bits of information. If we want to know the radius of the Earth or the size of an espresso grind, we no longer have to remember the answer, nor even really to have a feel for the answer, instead we can almost immediately find webpages that tell us (here and here).

And yet, this answer seems unsatisfactory. While there is an awful lot of information available to us at the tap of a phone, it is questionable whether that information translates to our own knowledge. Although collectively we can understand amazing things such as gravitational waves, individually we may struggle to explain how a toilet works. We need the plumber’s knowledge as much as we need that of the cosmologists. Does it matter who knows? What level of knowledge does someone need to have to say that they ‘know’ something?

coffee long black gentlemen baristas
Taking time to stop and think about what it’s all about. My coffee at The Gentlemen Baristas

Perhaps this appears a very strange cafe-physics review, where is the physics? But part of the rationale behind Bean Thinking is also to slow down and contemplate and it seems that The Gentlemen Baristas offers the perfect environment in which to do so. A café that mixes the new with the old, a space in which the practices of one can inform the other.

So to return the thought train to the area local to the Gentlemen: Writing in the second century AD, the Stoic philosopher Marcus Aurelius wrote

“In death, Alexander of Macedon’s end differed no whit from his stable-boy’s. Either both were received into the same generative principle of the universe, or both alike were dispersed into atoms.“

It is a quote you will probably find very easily via a search engine, or slightly less easily if you read his “Meditations”. But it is perhaps worth pondering, in what sense we ‘know’ what he was meaning. Strolling past the ribbons and messages memorialising the (estimated) 15,000 people who lay buried in the ‘outcast’ graveyard of Crossbones, what about our own attitudes to our modern outcasts? And perhaps more tellingly, our attitudes to those in positions of power or influence?

Perhaps it will take a lifetime of understanding our personal reactions to the poor, the prostitutes, the homeless and the powerful to really know what Aurelius meant. It certainly requires of us that we stop, pause and reflect on the knowledge that we come by. So it is far from obvious that it benefits us to use the wifi password rather than sit, slow down and contemplate. And where better to do so than in a friendly café with good coffee and seats to ponder the moment?

The Gentlemen Baristas can be found at 63 Union St, SE1 1SG

 

 

Categories
Coffee review Observations

An odd one out at Shot Espresso, Parsons Green

tubes playing with perspective Shot Espresso Parsons Green
The view from the ‘conservatory’ in Shot Espresso, Parsons Green

A couple of weeks ago we were wandering around the Parsons Green area in search of a coffee. Near the station, was a small shop front with a familiar name. Not quite a chain, but the logo of Shot Espresso is well known to me from its relatively new outlet in Victoria. It turns out that the Parsons Green branch is one of four outlets for Shot Espresso which started just around the corner in Fulham.

The staff were very friendly and took our order before we found seats at the back of the café. Although there was plenty of seating near the counter it was all taken, clearly this is a popular haunt on a Saturday afternoon. This did mean however that we found a cosy table in a small but very bright area, almost like a mini-conservatory. It seems we often have a long black and a soy hot chocolate and today was no exception. The hot chocolate was apparently perfectly well done my long black was fruity and drinkable, offering a perfect flavour backdrop against which to appreciate the area of the café.

Then a tricky decision. Ordinarily, I am not a fan of reviewing chains (though there is a question, does four branches equal a chain or not?). I’m a great fan of what an independent coffee shop can bring to an area, a place where the owners can be found behind the counter and you can really get to know a friendly space. However Shot Espresso is not that large a chain and the branch at Parsons Green had the feel of a local. The staff when we were there certainly took an interest in the running of the shop and, another factor in my decision to review, there were so many things to notice here.

infinity, shot espresso
Infinite tables? The logo on the table next to us at Shot Espresso Parsons Green.

I’ve already mentioned the light in the conservatory, there were also the light fittings in the main part of the bar. Wooden outlines of cubes around a light bulb that played with your image of perspective. On the tables next to us, the symbol of the manufacturers was similar to the symbol of infinity, why? But then, an oddity that prompted a mathematical curiosity. On each table was a miniature watering can holding sugar. It’s almost a game:

You have a mug of coffee, a cup of hot chocolate, a doughnut and this watering can on your table. Which is the odd one out and why?

If you answered the watering can, you would have been correct. Topologically the mug of coffee, cup of hot chocolate and the doughnut are the same whereas the watering can is quite different. What does that even mean? It means that in terms of shape, a doughnut can be morphed into a coffee mug which can clearly be morphed into a tea cup as they each have one hole through them. The watering can however has multiple holes, not just to hold it and to let the water out but also, in this ornament design, at the join of the body to the spout (look carefully). This means that there is no way that you can transform a watering can into a doughnut, they are different categories of shape.

table at Parsons Green Shot Espresso
A coffee cup and a miniature watering can. But which has more in common with a doughnut?

This field of mathematical study (which is known as topology) has, in recent years, taken on enormous significance to physics in terms of understanding some odd effects including the way that some materials conduct electricity (or not). Indeed, it has become so important that it was the subject of the 2016 Nobel Prize (you can read the citation here). And yet, even for someone who works in solid state physics and should have a mathematical background, trying to get my head around this subject is extremely difficult.

Which got me thinking about something similar. When teaching, it is sometimes apparent how much mathematics appears as if it is another language. And in parallel with language, it requires a fluency to appreciate its beauty. And further, even with a fluency, to appreciate some use of the language requires more than just fluency but immersion, a concentration, an attention to the words. Perhaps an analogy is needed. Although fluent in English, I do not usually immerse myself in reading it. Consequently, I find the poetry of John Betjeman amusing and ‘readable’, but the poetry of Gerard Manley Hopkins very difficult. With patience, and advice from others, occasionally I can gain a flash of insight into a poem of Hopkins and realise the brilliance of the language but more often I struggle. What I would never imagine doing is saying “I can’t read English, I was never good at it in school”.

And it is here that it seems to me the parallel with mathematics ends. For while we can have fun with algebra, understand some of the beauty in calculus and perhaps struggle with topology, we nonetheless seem happy in our society to say “I can’t do maths, I was useless at it in school”. We accept boasts about mathematical illiteracy when we would blush to say similar things about our native language (whether it is English or another language).

Why is that?

watering can, Shot Espresso, Parsons Green
A closer look at the watering can. The number of holes in the join to the spout would make this useless as a plant watering device.

Surely there are few who are genuinely mathematically illiterate, at least, not to the extent that it is ‘boasted’ about within society. Indeed, you find many who are happy to admit that they don’t “do” maths, actually just mean that they would prefer to use their phone to calculate something. Just as with a spoken language, the language of mathematics requires practise. For it is practise that allows us to appreciate the fun of mathematics just as it is practise that allows us to read poetry. Why do we deny ourselves the fun of a language because it is fashionable to admit illiteracy in it?

If you would like to push yourself with some mathematical poetry, you can read about topology, coffee and doughnuts here or in more detail here and more information on the 2016 Nobel Prize can be found here. In the meantime, if you see something mathematically beautiful in a café, please do share it, either here in the comments, on twitter or on Facebook.

Enjoy your coffee, tea or doughnuts.

Shot espresso can be found at 28 Parsons Green Lane, SW6 4HS

 

 

 

 

Categories
Coffee review Observations Tea

Light and gravity at Tab x Tab, Westbourne Grove

drinks in ceramic mugs, Westbourne Grove
A soya hot chocolate and my black coffee at Tab x Tab

Earlier this summer, a new café opening on Westbourne Grove attracted a lot of attention. “Tab x Tab” quickly received reviews from Brian’s Coffee Spot (who noted the unusual espresso machine), Bean There at and Doubleskinnymacchiato. Bean There at also suggested that there should be plenty to ponder at Tab x Tab when I finally got the chance to get there. And so, a trip to this café had been on the agenda for a fair while.

Wandering into the café, it seemed exactly as described by the reviews: clean, sharp interiors in a modern building. It was fairly crowded when we arrived just after lunch and so we ordered before taking a seat at the bar (two of the few seats left). I had a long black while my fellow imbiber had a soya hot chocolate. The drinks arrived in those distinctive mugs mentioned by doubleskinnymacchiato (and pictured above). As we had just had lunch, on this occasion we didn’t check the edibles on offer but with plenty of other reviews of the coffee and the cake, I’m sure that you’ll find recommendations there (I understand the avocado on toast with cashew nut is well worth trying).

Graphite, double layer graphene, stacked hexagons
Plant on two slates at Tab x Tab, Westbourne Grove

Sitting down to enjoy our drinks, the first thing to notice was that Bean There at was absolutely right. Despite the slightly minimal and elegant decoration, there were plenty of things dotted around that were slightly quirky. Firstly there was the plant that had been placed on two hexagons of slate that had been ever so slightly displaced from each other, presumably for aesthetic effect. Could this link to graphene and graphite with their strong intra-layer bonding and weak interlayer bonding (so the hexagons of carbon in graphite slide over each other)?

Then there was the selection of items for sale that also provided food for thought. Books and other items from the School of Life, something to think about as you stop with your coffee perhaps. In the other direction, on the counter top, a couple of Venus Fly Traps were waiting for their lunch. There is so much we have yet to learn about the symbiotic relationships between plants and animals and especially between plants and fungi. As we looked further around the café, there was something else a little odd. Just as the name “Tab” was written both the correct way and upside down in the window, so the plants in the hanging baskets were hanging upside down.

which will win, gravity or light
Plants hanging upside down in the window at Tab x Tab

This seemed a bit strange in itself. Plants have a tendency to move upwards towards the light. This behaviour of plants (and trees in particular) provides one way to identify which way is south when walking in the country without a compass¹. It is odd to see a plant growing downwards and suggests that the plants in the window are regularly rotated so that they don’t try to reach up. As Simone Weil wrote “Two forces rule the universe: light and gravity”². Which would win in the end? To be fair, Weil was not referring to the light that streamed through the windows in Tab x Tab giving the plants the force they need to move upwards. Nonetheless, whether one is thinking literally or analogously, it is an interesting question what pulls us down, what brings us up?

There is a story that Newton arrived upon his idea of universal gravitation by contemplating a falling apple. Considering that the plants were approximately 2m above the floor level, and using the fact that the acceleration due to gravity, g,  is 10 m/s², if the plants were to fall from their hanging position, they would take:

s = ½gt²

t = 0.6 seconds

to fall and smash to the ground*. While this brings to mind Newton’s experiments dropping pigs bladders filled with liquid mercury from the dome of St Paul’s Cathedral, it is worth instead thinking more about the universal nature of the gravitational force. This is of course what made Newton’s idea of gravity different from the theories that had preceded it. People had known that if an apple fell from a tree (or a plant fell from its hanging basket) it would fall to Earth. What was key to Newton’s idea was that what applied to the apple, applied to all other masses too. The same maths that could be used to calculate how fast a plant dropped, could be applied to the Moon. So, if this was the case, could we calculate the orbital distance of the Moon in the time it took us to enjoy a coffee at Tab x Tab? We know that the Moon’s orbital period is τ = 27.3 days (2.36 x 10^6 seconds) so assuming that the gravitational force acting on the Moon is balanced by the centripetal force, we can equate the two:

Gravity: F = GMm/r²

Centripetal: F = mv²/r

Where, G is the gravitational constant (6.67 x 10^11 Nm²/kg²), M is the mass of the Earth (5.97 x 10^24 Kg), m is the mass of the Moon and r the moon’s orbital distance (which is what we want to calculate). If we assume that the Moon travels in a circular orbit (not quite true but not a bad first approximation), then we know the speed, v, of the moon in terms of the orbit period, it is just:

v = 2πr/τ

A bit of re-arrangement and some plugging in of values leads to a back-of-the-envelope value for the Moon’s orbital distance of 383 000 Km. A value that does not compare badly at all with the average distance of the Moon given by NASA as 384 400 Km.

Perhaps if we’d stayed for an additional flat white we could have refined the calculation somewhat and so obtained a value closer to reality. Nevertheless, the fact that the force that is pulling the plant down at Tab x Tab is the same as is pulling the Moon around the Earth, and that we can quickly check this (and get an approximately correct answer to our calculation), is one of those ‘wow’ moments in physics. Realising the universality, and elegance, of certain mathematical relations. So perhaps it is entirely appropriate that this thought train of mathematical elegance was prompted by the quirky but aesthetic elegance you will find at Tab x Tab.

Tab Tab can be found at 14-16 Westbourne Grove, W2 5RH

¹ The Walker’s Guide to Outdoor Clues & Signs, Tristan Gooley, Hodder & Stoughton, 2014

² Gravity and Grace, Simone Weil, Routledge (1995 vsn)

*Although you could use a more accurate value for g, the error on the estimate of the height of the plants makes such precision potentially misleading. The value 0.6 seconds is absolutely a back-of-the-envelope, calculation.

Categories
Coffee review Observations Science history

Phlogiston in the Watch House

Watch House coffee Bermondsey
The Watch House in Bermondsey

At the end of Bermondsey St, tucked away in an odd looking building on the corner, is a café known as the Watch House. Stepping inside you are met with a very strange impression: this is far from your normal rectangular room. Instead an octagonal space, complete with Victorian style tiling and wood burning stove greets you. There are about five small tables inside, which were all occupied (some shared) when we arrived late in the lunch hour. So we sat at a table outside, although there was also bench seating on the other side of the door and a lovely park just next door, the old St Mary Magdalen graveyard.

The building itself dates from the time when the “watch house” was the base for a makeshift local constabulary that would monitor the local area ensuring that no body-snatchers were operating in the graveyard next door. The body snatchers used to ‘acquire’ recently buried bodies for use in anatomy classes at the capital’s teaching hospitals. Nowadays, as with many other disused burial grounds in London, the graveyard next door has been transformed into a park. On the other side of the café, a drinking fountain (the gift of a Henry Sterry Esq.) is embedded into the wall. An interesting feature reminding us of the drive to provide drinking water to London’s population both then and now with the newly installed fountains at the nearby Borough Market.

coffee at Watch House
What fantastic colour in this filter.

As I placed my V60 on the table outside, the light shone through it making the coffee appear to glow with a deep red tinge. Temporarily ignoring my normal idea that such transient beauty can’t be captured, I tried to photograph it, an endeavour that predictably failed to capture the full radiance of the cup. Nonetheless, the clear red coffee did not have significant sediment at the bottom of the cup. Perhaps this is not surprising, it was a V60. But nevertheless this lack of sediment has a connection with the water fountains both at the Watch House and at Borough Market and the wood burning stove. You could even make a macabre link to the graveyard next door. But without pursuing that last one too much, the link is Antoine Lavoisier (1743-1794) and the transmutation, or not, of water into earth.

The problem was this: In the early seventeenth century Jon Baptist Van Helmont had planted a 5lb (2.3 kg) willow tree into a pot of soil of mass 200 lb (91 kg)¹. He covered the pot of soil and only allowed rainwater into the tree/pot system for 5 years. At the end of his experiment, the mass of soil was unchanged but the willow tree was now 169 lb 3 oz (76.8 kg). Clearly, the “element” water had transmuted into the “element” earth* and so added to the mass of the tree. A few years later and scientists boiling distilled water (which had of course been purified by previous boiling) noticed that there was always a solid residue left after the water had boiled away². Another piece of evidence for the transmutation of water into earth.

Lavoisier, who became known as the father of modern chemistry, thought differently. He had been interested in obtaining clean, safe drinking water for the inhabitants of Paris and had noticed that when rainwater was repeatedly distilled, the amount of solid residue left after boiling decreased with each distillation. How was this reconcilable with the idea that each time you boiled water part of it became the element earth? But if water wasn’t ‘transmuting’ into earth, what could explain the solid residues observed by the other scientists of his day?

Lavoisier suspected the potash or soda used in making the glass vessels used in the experiments. He thought that this could be dissolving out of the vessels when the water was boiled, leaving what looked like a solid residue at the bottom of the cup². To demonstrate that this could be the case, Lavoisier took a sealed container of water called a ‘Pelican’ (which has two arms to allow the water vapour to cool and drip back down to the base of the unit). He first weighed the water and the vessel, separately and together and then boiled the water in the sealed pelican for 100 days. After 100 days he weighed the container-water system again. The total mass had not changed. However, when they were weighed separately, something odd had happened. The glass vessel (the pelican) had lost some mass while solid salts had appeared in the vessel. Although these salts weighed slightly more than the mass lost by the pelican container, Lavoisier considered the discrepancy within error thereby showing that the ‘transmutation’ observed by other scientists was actually salt dissolving out of the glass vessel.

Lavoisier’s experiments were an important contribution to the development of experimental method as well as a refutation of the old idea of the transmutation of the elements earth-air-fire-water.

Lavoisier, drinking fountain, Bermondsey
The fountain on the side of the Watch House. How had a need for supplying the public with drinking water shaped our scientific thinking?

Which leaves one last connection: the wood stove. Since the dawn of humanity, there has been the question “what is fire?”. By the time of Lavoisier, fire was explained by the idea that matter contained more or less “phlogiston”. Something could catch fire if it contained a large amount of phlogiston, it would not ignite were it to have too little phlogiston³. One observation clearly explained by the phlogiston theory was the observation that a burning candle, covered by a glass bell jar, would extinguish itself. The idea was that the candle (which contained phlogiston) released that phlogiston into the air. If the candle burned within a jar, the air surrounding the candle would became saturated with phlogiston. Once saturated, the air could ‘hold’ no more phlogiston so none could escape the candle wick. This would mean that the flame would go out.

Lavoisier, now recognised as one of the three independent co-discoverers of oxygen, showed that oxygen, not phlogiston, was needed for burning to occur. The question is how did he do it? And a question for you, when you are enjoying your sediment free delicious coffee next to a warming wood fire: how would you?

 

*to be fair to Van Helmont, it is hard to blame him for arriving at this conclusion. It was still a few centuries before photosynthesis was discovered and the idea of the four elements of fire, earth, water and air was still active in his time.

The Watch House is at 199 Bermondsey St, SE1 3UW

¹”Lavoisier in the year one”, Madison Smartt Bell, Atlas Books (2005)

²”Lavoisier”, Jean-Pierre Poirier, University of Pennsylvania Press, (1996)

³”From phlogiston to oxygen”, John Cartwright, Hatfield (2000)

 

Categories
Coffee review Observations slow

Constructive interference at Frequency, Kings Cross

exterior of Frequency Kings Cross
Note the tiles. Frequency, Kings Cross on a rainy day.

It was a rainy afternoon when we ventured to Kings Cross and into Frequency. Suggested by the London’s Best Coffee App as the closest café to our then location, we made our way through puddles and rain onto Kings Cross Road. At that point, a brain-freeze meant that we couldn’t see where Frequency should be. The map on the app was implying that we were extremely close but there didn’t seem to be a café around. Then we saw it in front of us! The striking black and white tiling on the floor somehow hiding this shop-front from view.

The tables inside matched the tiling outside. Black and white triangles meeting at a point. My long black (from Workshop) was placed close to the intersection of these triangles. The coffee arrived in a mug, more cylindrical than standard coffee cups and so closer to mathematical models of coffee cups that are used in explanations of convection and rotation in the cups. An interesting change of aesthetic that also changes the internal dynamics of the coffee. A nice touch was that the mugs were also coordinated with the tiling, though to be fair I hadn’t noticed that at the time.

The coffee itself was extremely fruity, a lovely warming brew to enjoy while watching the rain outside. The interior of the café meanwhile was decorated with a lot of wood around together with a couple of music stands. Perhaps the music stands make sense in a café named Frequency. Indeed, according to the review on London’s Best Coffee (or as it is now known, Best Coffee), there are plans to build a music recording studio here as well as having live musical performances. However, also mentioned in that review was the fact that this café had been designed and built from scratch with the help only of online tutorials. Which makes a particularly resonant connection with something I noticed here.

mug of coffee at Frequency
Coffee at Frequency.

What caught my eye as I contemplated this café was the one bit of bright colour on the ceiling. It was also something that hints at problems that can crop up when you design and build your own electrical circuits: Parallel wires (in this case leading to the lightbulbs). Perhaps in the café, these were intended to represent music staves, certainly that would fit in the theme. However to an experimental physicist who dabbles in designing pieces of kit for electrical measurements, these parallel lines leading to a light mean something entirely different.

They mean noise.

When you are designing a piece of electrical equipment to be used for measuring voltages across an unknown material, there often ends up being a lot of wiring in the probe as well as the bit at the end of the instrument that you are actually interested in. Some of this has a practical purpose. Often we want to measure something when it is very cold so it has to be on the end of a metal rod that is inserted into a vat of liquid nitrogen or helium or that is held in a strong magnetic field. When designing the probe, the bits of wire leading to the interesting bit at the end of the rod can be almost as important to consider as the measuring bit itself.

To see why, perhaps you remember putting compasses around a wire carrying an electric current? As the electric current is switched on, the compass needles move indicating that the electrical current generates a magnetic field. The basis of electric motors and dynamos, the idea is that an electrical current will generate a magnetic field and a moving magnetic field would generate an electrical current.

transmission lines, electrical noise
The wires to the light bulbs in Frequency Kings Cross. Memories of transmission line lab experiments.

Now, imagine two parallel wires each carrying an electrical current. Both of them will produce a magnetic field, but if there is a varying current in one or other of the wires, the magnetic field will also be varying. And if there’s a varying magnetic field, it can induce a current in the neighbouring wire. In this way, electrical noise on one of the wires can be transmitted to the other.

Such electrical noise can be inconvenient if we are trying to speak on the phone and just hear a ‘hiss’, or if we are trying to listen to the radio and just can’t tune in. It could also be more problematic, imagine if there was a lot of electric noise on a machine measuring the electrical activity of your heart, an ECG. Consequently, there are whole books written on how to reduce electrical noise pick up. However one simple way to reduce a lot of the noise is to get rid of those parallel lines the like of which are on the ceiling at Frequency by twisting them together. The ‘twisted pair’ is a great way of making more sensitive electrical measurements. And if you wanted to reduce the noise further, you can shield the twisted pair with another conductor and ground (or earth) it.

The twisted pair works by reducing the magnetic coupling between the two wires. Of course, it may not be quite as immediately aesthetically pleasing as parallel wires on a ceiling but there is something quite elegant about a well made and shielded twisted pair properly grounded in an electrical circuit. And when you put everything together, ground it properly and see the noise from the electrical mains (at 50Hz) disappear, there is a certain pleasing effect from that too.

Café design as a clue to electrical design. Frequency can be found at 121 Kings Cross Road, WC1X

 

Categories
Coffee review Observations slow Sustainability/environmental

A need for religion at Continental Stores, Russell Square

exterior of Continental Stores
Ghosts of shops past! Continental Stores on Tavistock Place

Many years ago Tavistock Place, now home to Continental Stores, was on my cycle route home. I can no longer remember whether the sign “Continental Stores” was visible then or whether it had a second sign over it. However, the faded red backdrop, the vintage font and the whole feel of the frontage does make “Continental Stores” (the café) stand out a bit from the crowd. Continental Stores is run by the same people who run Store St Espresso on Store St. but much of the original decoration of the café has been kept from the old shop that previously occupied this space. And although this ‘new’ branch is now more than three years old, for various reasons I’ve never quite got to visit until a couple of weeks ago.

We arrived fairly late, just half an hour before closing, and managed to get a long black before the espresso machine (which was apparently having a bad day) finally packed up. Although filter coffee was available, this is not the case when you arrive so close to closing. The coffee was however very drinkable and the window seat provided a great place to watch people pass by. Bubbles formed around the edge of the coffee, reflecting the light streaming through the window in this airy café. White mists skitted over the surface of the drink. There was plenty to consider in the café too, from the oil paintings on the wall to the subtle green colour of the glass separating the interior of the café from the bar area (for more on glass colours click here). A large amount of science in a cosy place. However today’s train of thought took a somewhat different direction. That day, sitting in the café, prompted a thought train to develop in a more introspective direction: what does climate change denial have to do with personal integrity and the need for a continuing dialogue between science and religion? And what does that have to do with coffee drinkers?

Incredibly, it started with a map.

glass and map interior Continental Stores
So much to contemplate! From glass to the map.

On the wall in the main area of the café, behind the counter, is a map depicting the world. Although there is a photo on this page, there is a far better one in Brian’s Coffee Spot review of Continental Stores which can be found here (scroll through the gallery to find it). Also on the map are two circular depictions of the Polar regions. That fact, that the poles are illustrated separately and that the map is a rectangular impression of our spherical home impressed on me the knowledge that it is extremely difficult to truly represent our globe on a flat piece of paper. All maps are projections and the one at Continental Stores is the familiar cylindrical projection where you imagine a cylinder of paper wrapped around the equator of the Earth and then project the profile of the countries around onto it.

A few years ago a Malaysian-Chinese lady, now in her 70s told me a story about growing up in Malaysia (then Malaya) under British colonial rule. At school it was always impressed upon her how much larger Britain was than Malaysia, you could see it just from looking at the maps (which were always of the cylindrical projection as displayed at Continental Stores). It was only later that she realised the importance of map projections. Although Malaysia, at the equator, was fairly well represented by the cylindrical representation, Britain, being relatively closer to the poles, was stretched and so appeared much larger. Britain is in fact larger than the Western Malaysia peninsular but not to the extent that it appeared from the map. Had the map projection been used as a subtle political tool justifying Britain’s rule over Malaya*?

Similar thoughts occurred to me recently with some of the comments that have followed hurricane Harvey in the US (and the floods in south Asia that have killed more than 1200 people but have sadly been far less reported here in the UK). Was the intensity of the hurricane, and the fact that we are experiencing similarly intense storms more frequently, a consequence of climate change?

message inside Continental Stores
From the table to our planet. A message with resonances.

Although that’s an interesting question, it’s not the one that I would like to consider today. Instead, it’s the response on social media generated by data about the frequency of the hurricanes and their strength. “Why are you only showing weather information for the past X years, if you look back further/look more recently…” etc. It is the same with graphs showing global temperatures as a function of time. People ask “Why are they plotted that way, if we looked back further/zoomed in a bit more….” It seems that there is an accusation behind many of the questions; there is doubt about the integrity of the scientist who circulated the graph. What is at the root of this?

When writing a scientific paper (even on a relatively uncontroversial topic like magnetism), there is frequently a lot of discussion about exactly how to present the data. The graphs need to be clear enough and on a scale that the ‘message’ of the paper is delivered quickly. But equally in a way that does not misrepresent the data. Then, different authors have different ideas on aesthetics. The final graph is a balance between these. So why is there such distrust of similar graphs presented on subjects such as climate change? Are we so used to being sold messages in adverts that we immediately suspect the scientists of an evil motive, trying to persuade us to ‘buy’ an ideology?

Clearly there are occasions on which data is presented in a manner to impress rather than to reveal, as was the case with the map. Though even with the map, there is some ambiguity. Some cylindrical projections can be helpful for navigators as lines of latitude and longitude cross perpendicularly. There are times when such a representation would be useful. So when we generate, share or read such  graphs, we need to ask ourselves questions about our reaction to them. Are we representing the data truthfully? Are we trying to make the data fit into opinions that we already hold? These questions apply equally whether we are creating the graph or if we are seeing it on social media and reacting to it.

black coffee Continental Stores
Bringing it back to the coffee. The bubbles reflect the light from the windows. Taking time to contemplate the drink gives us space to reflect.

These considerations generate questions of their own. What do we think science is? Do we believe in the existence of truth? What is truth anyway? What are my motives in sharing/reading this piece of information; am I trying to understand the world or manipulate it to my advantage?

Which is just one reason (of many) that a respectful dialogue between science and the humanities, between scientists and theologians is desperately needed. Religions and philosophies have been asking questions about the nature of being, questions of truth and motive for millennia. Tools such as the examination of conscience have been developed by religious traditions to allow us to interrogate our own motives and to start to understand our own behaviour. In a week when it was revealed that more than 50% of people in the UK describe themselves as having ‘no religion’ it seems to me that, whether we believe in a religion or not, many of us would benefit from such an examination of conscience before we hit ‘retweet’, ‘like’ or ‘share’. Questioning our motives before creating, sharing or commenting. But such tools require space and the time taken to slow down, perhaps in a café, to deliberate on our own attitudes. Time that is needed to help us to see if it is our behaviour that needs amending before we question the integrity of others.

Such deliberations often don’t have conclusions but instead open up more questions. The fortunate consequence of which is that it becomes imperative that we spend more time contemplating our coffee in quiet, welcoming and thought provoking environments such as that found at Continental Stores.

Continental Stores can be found at 54 Tavistock Place, WC1H 9RG.

*I have kept the name of the country Malaysia as it is now known apart from when referring to the time when Britain had colonised it and called it “Malaya”.