Category: Coffee review

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Coffee review Coffee Roasters Observations Science history Tea

Good vibrations at Vagabond, Highbury

black coffee, Vagabond, Highbury
A good start to the day. Coffee at Vagabond.

A long black, flat white (with soya milk) and a tea. Yes, you could say we spent a fair while at Vagabond in Highbury the other week. It was a lovely space to catch up with an old friend again. There were plenty of comfortable seats and the staff were definitely friendly, supplying us with coffee and space to chat for a while. The coffee was good (Vagabond are roasters as well as a café) with batch brew and Aeropress/drip on offer together with the usual selection of coffees and other drinks. Tasting notes were on a black board behind the counter while on the wall, also behind the counter, was a drawing of a tongue taste map. While the science of this has been disputed, it does serve as a reminder for us to sit back and properly appreciate – and taste – what we are drinking.

Above the espresso machine was a long rectangular sign that said “coffee in progress”, suspended by four cables, one at each corner. Coffee orders were placed onto this sign allowing the baristas to keep track of who ordered which drink. Given how busy this café occasionally got (and we weren’t even there for lunch), it seems that this is a very handy system. Each time an order was placed on the sign, the whole sign oscillated, rather like a rigid trampoline. Even if you had not seen the note placed on the sign by the barista, you would get a clue, a piece of evidence, that something had just happened by the vibrations long afterwards. Perhaps you may say that the sign was some sort of “order-detector”.

order detector oscillation espresso machine
The “order-detector”: sign at Vagabond in Highbury

Or at least, that is what you may say if you were thinking about the LIGO (Laser Interferometer Gravitational waves Observatory) detectors that, back in 2015, detected the gravitational waves produced by two merging black holes between 700 million and 1.6 billion light years away. Not only do these detectors have similarities to the order-detector sign at Vagabond, the beauty of the LIGO detector is that you can start to understand how it works by staring into your coffee. The LIGO experiment consists of two detectors. Each LIGO detector is an L shaped vacuum tube (4km long) with a mirror at each ‘end’. A laser beam is split between the two legs and reflected back by mirrors at the end of each L. When the reflected laser beams return back to the detector at the corner of the ‘L’, how they interact with each other is dependent on the exact distance that each laser beam has travelled between the mirror and the detector. Think about the bubbles on the surface of your coffee. These colourful bubbles appear as different colours depending on the thickness of the bubble ‘skin’. You may remember being taught that, exactly as with oil slicks on water, it was about the constructive and destructive interference of the light waves. As each ‘colour’ has a different wavelength, the colours that destructively interfere change with the thickness of the bubble skin. You can determine the thickness of the bubble by the colour it appears.

LIGO photo
An aerial photo of the LIGO detector at Hanford. The mirrors are at the ends of the tubes going away from the main building. Image courtesy of Caltech/MIT/LIGO Laboratory

In the LIGO experiment, there is only one wavelength because the light is coming from a laser. So whether the detector registers an intense laser beam or the absence of one, depends on whether those two beams coming back from the mirrors interfere constructively, or destructively. (A deeper description of the technique of “interferometry” can be found here). As the gravitational waves emanating from the collision of the black holes encountered the mirrors at the ends of the L’s in LIGO, so each mirror wobbled a little. This small wobble was enough to change the intensity of the laser light received by the detector and so reveal that the mirrors had moved just that little bit. In fact, the detectors are so sensitive that they can detect if the mirrors move by less than the diameter of a single proton. Given that this is a sub-atomic distance, I don’t think I can even start to relate it to the size of an espresso grind, even a Turkish coffee grind is millions (billions) of times larger than the amount that these mirrors moved. Yet this is what was detected a couple of years ago in the now famous announcement that gravitational waves had been detected and that Einstein’s predictions had been shown to be true.

Watching the “coffee in progress” sign oscillate at Vagabond, it is clear how much engineering has gone into isolating the mirrors at LIGO enough that they do not move as people walk by. Yet perhaps it is interesting that, nonetheless, one of the final refinements of isolating the mirrors from the vibrations of the earth involved changing the material for the cables that suspended them, just as with the sign at Vagabond. You can learn more about the engineering behind this incredible feat of detection in the video here, or you can go to Vagabond, enjoy a lovely coffee and think about the physics of detection there.

Vagabond (Highbury) can be found at 105 Holloway Road, N7 8LT

If you would like to hear what the collision sounded like, follow the link here.

 

Categories
Coffee review General Observations Science history

Some perspective at Over Under, Earls Court

Over Under Coffee Earls Court
Follow the arrow! Over Under Coffee in Earls Court.

Whenever I’m heading somewhere that I haven’t been to for a while, I check the London’s Best Coffee app to see if any new cafés have popped up in the area since my last visit. So when I was in Earls Court recently, I was very happy to be alerted to a new café on the map with a review by Beanthereat.

Over Under Coffee is at 181A Earls Court Road but is tucked around the corner from the main road and so thank goodness for the helpful arrow (and the map which told me I should be on top of it). Once found, we ordered coffee and banana bread and took a table to sit down. The friendly staff behind the counter were quite confident of the ingredients in the banana bread as it is made locally by a lady in Fulham (whose name I have sadly forgotten). The coffee and banana bread formed a great combination for a mid-morning snack. Coffee is roasted by Assembly roasters over in Brixton and came with lovely interference patterns in the bubbles on the surface together with dancing white mists, which never fail to fascinate me.

On the table next to ours was a small Kilner jar for sugar and two succulent plants. The Kilner reminded me of the use of air valves in coffee packaging (which are non-recyclable plastic) and the interesting experiment by Roasting House coffee roasters to investigate whether they are actually needed for freshly roasted coffee (which you can read about here). However it was a picture above the table that prompted the thought-train for today’s Daily Grind. A charcoal sketch, the picture featured a tree in the foreground with a fence behind it. From a very early age we are taught how to represent 3D objects on a 2D sheet of paper, the idea of perspective seems ingrained on our minds. But how intuitive is it really?

perspective in coffee
A picture at Over Under. Note the smaller reflections of the (more distant) light fittings.

Although the ancient Greek artists could convey an idea of depth in their art, the development of a mathematical understanding of perspective only came with Filippo Brunelleschi (1377-1446), although a written account of the mathematics of perspective did not arrive until Leon Battista Alberti (1404-1472). Alberti’s method for drawing in perspective used not just a vanishing point, but an additional diagonal vanishing point in order to construct a sense of depth and an accurate depiction of perspective (a description of Alberti’s method is here). The development of the understanding of perspective during the Renaissance meant that for some paintings, the ‘viewing depth’ can actually be calculated, while other artworks managed to create optical illusions whereby objects would jump out at the viewer as if they are in 3D. Works such as Andrea Pozzo’s ceiling in the chiesa di Sant’Ignazio in which a flat ceiling appears magnificently domed. Or, closer to home,  Samuel van Hoogstraten’s work in the National Gallery in London in which the viewer looks through a peep hole to see the interior of a house complete with a dog that appears to be sitting up inside the painting. Such paintings required a knowledge of the mathematical rules behind the depiction of perspective. Isn’t it surprising that the understanding of these rules is so recent?

Over Under Earls Court
Coffee with bubbles showing interference patterns at Over Under Coffee

Another art work with an interesting use of perspective that will bring us, in some way, back to Over Under Coffee is Raphael’s fresco “School of Athens“. The two figures of Plato and Aristotle stand at the centre of a diverse group of philosophers including Socrates, Zoroaster, Euclid, Diogenes the Cynic and, possibly, an image of Hypatia of Alexandria. Although the use of perspective for the architecture draws your eye towards the centre of the picture, two spheres (held by Zoroaster and Ptolemy) on the right hand side of the picture are drawn as circles rather than ellipses. Spheres viewed from an angle should be represented as ellipses if drawn correctly according to the rules of perspective. Did Raphael make an error in perspective (that may work better for our eyes?) or is the degree to which these two spheres are distorted within the limits of the fresco brush and so not visible in the picture? An episode of Radio 4’s In Our Time discusses this picture at length including a deep conversation about the significance of Plato pointing upwards towards the heavens and Aristotle indicating towards the Earth. Plato’s wisdom and Aristotle’s knowledge, above and below, much like the weave logo that brings us back to Over Under Coffee.

Over Under Coffee can be found at 181A Earls Court Road, SW5 9RB.

 

 

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Allergy friendly Coffee review General Observations Science history

Thinking space at Le Peche Mignon

Coffee in Le Peche Mignon, Highbury, Islington
Le Peche Mignon in Highbury, hidden down a side street.

It was a balmy February morning when I met an old friend at Le Péché Mignon on Ronalds Road near Highbury and Islington. I had first come across Le Péché Mignon a few months ago when I had had a lovely coffee (and a great cake, I remember the staff being very helpful to check the ingredients for my nut allergy) but too little time to properly think about the space. So, when the opportunity arose to meet a friend (who I have known since we were both 5 but haven’t seen for many years) near Islington, I jumped at the opportunity to meet there.

This small but delightful café seems to be very popular. Both the bench seat in the window (where I had sat last time) and the long, sharing-table in the middle of the café were practically full by the time we arrived in the mid-morning. Fortunately, there was plenty of space in the quiet garden at the back for us to catch up for a couple of hours (and a couple of coffees!). The coffee is roasted by Monmouth, the Americano was very well done and there were quite a selection of pastries and salads on offer. One wall of the café was lined with bottles of wine while Carambars were available to purchase next to the counter.

brick wall at Le Peche Mignon
A join between two brick walls at Le Peche Mignon. How exactly are bricks made and why are they made that way?

The garden behind the café had plenty of tables and, even though it was February, it was warm enough for us to sit comfortably outside. One of the walls of the garden was formed by two sets of brick walls that had a join between them. The appearance of a separation between the walls, together with the weather, reminded me of the crack and the imminent demise of the Larson C ice shelf. However as this was probably too close to recent posts about climate change, I started thinking about defect structures in crystals instead. While pondering this though, my thoughts turned to an entirely different subject matter, the unusual toilet at Le Péché Mignon.

Just as the toilets in our old primary school, the toilet at Le Péché Mignon is outside, in the garden. This got us reminiscing about our old primary school which, during winter, regularly closed when the outside toilets froze (hopefully not a problem for the toilets at Le Péché Mignon!). And while the school has undergone significant renovation since then, it does get you thinking about the history (and engineering/science) of toilets. While this may seem an unpleasant subject for, what is after all a café review, please do bear with me because thinking about toilets can lead to surprising connections. For example, a recent New Yorker article about confirmation bias featured quite a discussion on toilets. How? It seems that while people generally tend to think that they understand how a toilet flush works, when asked to explain it step by step, they suddenly become far less confident. Our knowledge is not so great as we tend to think it is.

cup of coffee in Le Peche Mignon
From coffee cups to aeroplanes, the hardness and porosity of materials depends on the temperature that the starting materials were ‘baked’ at.

Which brings me back to Le Péché Mignon. The issue of flushing toilets became a problem for London in the mid-nineteenth century when the introduction of the “water closet” increased the volume of water flowing into the rather inadequate sewage system (if you are interested in the history of the toilet you can click here). The great engineer Joseph Bazalgette (1819-91) was commissioned to design and build London’s sewer system in which a network of tunnels were built across the capital. Bazalgette’s northern branch lies about 5 minutes walk north of Le Péché Mignon and runs from Hampstead Heath to Old Ford in Stratford. A distance of just 9 miles (14.4 Km), this particular tunnel has a remarkably steep gradient dropping at least 4feet (1.2m) every mile (1.6 Km). Imagine water flowing down a plug hole. The turbulence and speed of the water (ahem) flowing down this ‘drain’ means that Bazalgette had to think very carefully about how he lined this particular tunnel. If he had used ordinary bricks, such as those that make up the wall around the café’s garden, they would have eroded quickly with the turbulent motion of the water. Consequently, Bazalgette specified Staffordshire Blue bricks¹ to line this tunnel. During the manufacturing process, Staffordshire Blue bricks are baked at very high temperature (and in a low oxygen atmosphere) making them particularly resistant to erosion and to water absorption. It should not surprise us that the hardness, brittleness and texture of materials should be affected by the temperature at which they are formed after all, great care is taken about the temperatures at which chocolate is melted and allowed to re-solidify. Indeed, a vast amount of research is done to understand how different materials (from ceramics to metals) respond under different heat treatments. This research is important for applications as diverse as the walls of sewer tunnels to the design of aeroplanes. And, of course, to the design of better coffee cups, a thought with which we can return to thinking about this great little café.

Le Péché Mignon can be found at 6 Roland’s Road, N5 1XH

¹”The Great Stink of London…” Stephen Halliday, Sutton, 1999

 

 

http://www.plumbing-geek.com/howdoesatoiletwork.html

http://www.baus.org.uk/museum/164/the_flush_toilet

Categories
Coffee review Observations Science history slow Sustainability/environmental Tea

Seeing the light at Cable Co, Kensal Rise

coffee in Kensal Rise, Cable Co
Cable Co, coffee in Kensal Rise

It was fairly late on a February afternoon that we came upon Cable Co on Chamberlayne Road, (opposite Kensal Rise station). With a fairly ‘industrial’ type look, there are plenty of tables at the edge (and in the window) of the café at which to enjoy your coffee. There are also plenty of coffees on offer. Although I had an Americano, I noticed (too late) that pour-overs were available. Coffee is roasted by Climpson and Sons. As it was late in the day, the remaining cakes in the display case all looked to be nutty (or at least likely to be nutty) and so, sadly, I had to wait until I got home for my slice of cake. It was good coffee though, even without the cake, but in a bit of novelty the coffee came ‘deconstructed’, so I got to add the amount of water that I preferred, a nice touch.

Golden light from the setting sun streamed in through the windows (which is a navigation clue & tells you which side of the road this café is on). The effect of the Sun was to bathe the café in light and to silhouette our fellow coffee imbibers making the café take on a film-like atmosphere. The light had another effect though. The steam rising from both the jug of water and my espresso became far more visible than it would normally have been. I watched as the steam clouds formed vortices and turbulent patterns, one fluid (steam) moving through another (air). It was very difficult to catch this in a photograph, a fact that I took in support of my idea that it is impossible to catch the beautiful, beauty is necessarily transient (but my companion in these reviews took as evidence in favour of their idea that I really ought to use a “proper”, manual, camera and not my iPhone).

Steam, scattering, colour
Steam rising from hot water, seen at Cable Co, Kensal Rise

Still, those turbulent rising patterns of steam were visible and that implies that light was being scattered from the droplets of water in the steam. The size of the droplets influences the colour that we perceive when we view the steam clouds. If the clouds appear white, it is because the droplets that are scattering the sunlight have a diameter roughly equal to (or greater than) the wavelength of visible light. The wavelength of light varies between about 400 nm (violet) to 700 nm (red) which means that these water droplets have to be at least 700 nm across. To put this in perspective, the smallest particles of coffee in an espresso grind are about 10 μm diameter which is 14 x bigger than the droplets in the steam cloud.

Of course, how water droplets scatter light above a steaming coffee has implications for our understanding of why the clouds in the sky appear white (and why the sky is blue). Someone who did a lot of early work in understanding the way that light scattered off water droplets in air was John Tyndall (1820-1893). Tyndall was an experimentalist as well as a famous communicator of science. He regularly gave lectures at the Royal Institution that included demonstrations of the experiments that he himself was working on¹. One of these involved scattering light from water droplets (and therefore demonstrating why he thought the sky was blue).

Interior of Cable co
Light streaming into the cafe.

The idea is that sunlight scatters from water droplets differently depending on the diameter of the droplet. When the water droplets are approximately the diameter of the wavelength of red light, 700 nm, there is very little wavelength dependence to the light scattering. Practically this means that the droplets will appear white. If on the other hand, the droplets are much smaller than the wavelength of light, the light scattering starts to be wavelength dependent. So as the droplet gets smaller, blue light (short wavelength) gets scattered a lot by the droplets, while red light (long wavelength) is not scattered so much. This means that if you are looking at a cloud of steam formed by these small droplets at an angle between the sunlight and yourself (say, 90º), the cloud will appear to have a blue tinge. If on the other hand you look straight through the cloud at the sunlight coming in, it will have a red-hue because the blue light will have been scattered out of the cloud leaving only the red colours to come through.

The experiment can be easily demonstrated at home by using very dilute milk in water (see video here or further explanation here). If you put a few drops of milk in a glass of water and then look at the colour of the milky-water as a function of angle, you should see it change from red to blue as you move the glass relative to the light source. The connection with the blue sky seems clear, small particles (in-fact, they can be as small as molecules) scatter blue light preferentially and so, apart from at sunrise and sunset, the sky will appear blue. As Tyndall wrote:

“This experiment is representative, and it illustrates a general principle…. that particles of infinitesimal size, without any colour of their own, and irrespective of the optical properties exhibited by the substances in a massive state, are competent to produce the colour of the sky.”²

Cable Co is at 4 Bridge House, Chamberlayne Road, NW10 3NR

¹A Vision of Modern Science, John Tyndall and the role of the scientist in Victorian culture, U. DeYoung, Palgrage MacMillan, 2011

²Quoted in John Tyndall, Essays on a Natural Philosopher, Ed. WH. Brock, ND. McMillan, RC. Mollan, Royal Dublin Society, 1981

 

http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html

 

Categories
Coffee review Science history

In their Elements at Bean Reserve, Bangsar, KL

coffee in Bangsar at Bean Reserve
Bean Reserve, Bangsar, Kuala Lumpur. Note the logo on the window.

The first thing that struck me as I entered Bean Reserve in KL was the geometry. Somewhat hidden along a street behind Jalan Maarof, Bean Reserve offers a quiet space amidst the bustle of Bangsar. The 2D representation of a 3D object that is Bean Reserve’s logo is somehow mirrored in the choice of the tables and chairs that are contained in the cuboid space of this café. Triangular tables are arranged to form larger, quadrilateral tables. Circular stools nestle underneath square tables. Light streams into the café from a large window on one side of the room. The other side features a sliding door that was occasionally opened, revealing the desks of The Co, a co-working space that shares the building of Bean Reserve.

Although we only tried the drinks (an exceptionally fruity long black and a very cocoa-y iced chocolate), there looked to be an interesting selection of edibles on offer, with a bottle of chilli sauce stored behind the counter. Soy milk was available if you prefer non-dairy lattes and there were a good range of drinks on offer from nitro-cold brew to iced chocolate, just what can be needed in the heat of KL! Coffee is roasted by Bean Reserve themselves (who are both a café and a roastery), thereby providing the residents of (and visitors to) Bangsar with a seasonally varying range of great, freshly roasted coffee.

geometry at Bean Reserve
Triangular tables and circular stools.

The different geometrical features in the café immediately suggested Euclid to my thoughts. Written over 2300 years ago, Euclid’s The Elements was, for many years, the text book on geometry and mathematics. It is said that Abraham Lincoln taught himself the first 6 books of The Elements (there are 13 in total) at the age of 40 as training for his mind¹. Working from 5 postulates and a further 5 common notions, Euclid describes a series of elegant mathematical proofs, such as his proof of the Pythagoras theorem. And so, it may be appropriate that there is one more geometrical connection between the ancient Greeks and Bean Reserve: That sliding door that connects the café to the working space of The Co.

The space, occupied by The Co, behind the sliding door seems to be much larger than the café. But how much larger is it? Double the length? Double the volume? This is similar to the problem that perplexed the Delians. The idea is simple: Find the length of the side of a cube that has a volume exactly double that of a given cube. It is thought that the problem may have been formulated by the Pythagoreans, who, having succeeded in finding a method of doubling the square (see schematic), extended that idea to 3D. Could a simple geometrical method be used to double the cube? (There is of course the alternative legend about the problem having been given to the Delians by the Oracle)

A geometrical method for finding the length of a square with twice the area of a given square… now for 3D

It turns out that this is a tough problem, but one that may again have relevance for our world today. While researching this café-physics review, I came across a book by TL Heath² that had been published in 1921. In his introduction he wrote:

“The work was begun in 1913, but the bulk of it was written, as a distraction, during the first three years of the war, the hideous course of which seemed day by day to enforce the profound truth conveyed in the answer of Plato to the Delians. When they consulted him on the problem set them by the Oracle, namely that of duplicating the cube, he replied, ‘It must be supposed, not that the god specially wished this problem solved, but that he would have the Greeks desist from war and wickedness and cultivate the Muses, so that, their passions being assuaged by philosophy and mathematics, they might live in innocent and mutually helpful intercourse with one another’.“

 

 

Bean Reserve can be found at 8 Lengkok Abdullah, Bangsar, 59000 Kuala Lumpur, Malaysia

¹History of Mathematics, An Introduction, 3rd Ed. DM Burton, McGraw-Hill, 1997

²A History of Greek Mathematics, Thomas Heath, Oxford at the Clarendon Press, 1921

 

Categories
Coffee review slow

Pulp fiction in KL?

Freshly roasted coffee, Pulp, Papa Palheta, KL
Coffee on the cutting machine at Pulp

There have been a few great cafés opening up recently in Kuala Lumpur, including Pulp by Papa Palheta in Lucky Gardens. However the space that Pulp occupies is unrivalled: The old cutting room of the Art Printing Works. It really is geek meets hipster in this café, with old electric fittings and the original paper cutting machine housed alongside a fantastic range of freshly roasted coffee.

There is a great range of coffee on offer too. From pour-overs to espresso based drinks and cold brew, Pulp is a great place to discover a wide range of coffees. I had a pour over Ethiopian (Suke Quto) that was beautifully presented with tasting notes ready for me to enjoy. A nice touch was that the cup had been pre-warmed so I got no condensation around the rim of the mug when I filled the cup with coffee. The coffee itself was very fruity, presumably very lightly roasted in order to retain the fruity notes of the beans. (On a second visit I enjoyed a long black which was also very fruity though less so than the pour-over).

pourover at Pulp, Papa Palheta, KL
Taking time with a beautifully presented pour-over

Although there are plenty of seats in this café, on both occasions we visited it was crowded and hard to find a seat. It seems that this is a very popular spot for good coffee in KL, so do be prepared to share a table! Indeed, one of these ‘tables’ is formed from the old cutting machine itself, the machine that used to prepare the paper used for newspapers and books. Sipping coffee here, in a place steeped in the history of printing, it seemed only natural to consider the role in our current society of fake news and whether there is anything that we can do about it.

The issue of fake news or of exaggerated or incomplete news stories is not just limited to issues surrounding the recent US election. Reporting our experimental results honestly and our theories thoroughly underpins all scientific research. However, as funding decisions and employment prospects increasingly depend on publications in prestigious journals, question marks can start to hover over each scientist’s paper (the “publish or perish” problem). Does reporting a result honestly include waiting for that last result (that could contradict or delay the ‘story’ thereby making publication in “high impact” journals such as Nature less probable)? Do we read the papers of others thinking that they have reported everything as truthfully and fully as possible or do we shrug as their next paper (in a lower impact journal) reveals the ‘caveats’ on their previous work? The chemist and scientific philosopher, Michael Polanyi wrote in 1946:

“… Suppose scientists were in the habit of regarding most of their fellows as cranks or charlatans. Fruitful discussion between them would become impossible…. The process of publication, of compiling text books, of teaching juniors, of making appointments and establishing new scientific institutions would henceforth depend on the mere chance of who happened to make the decision. It would then become impossible to recognise any statement as a scientific proposition or to describe anyone as a scientist. Science would become practically extinct.“∗

Pulp, Papa Palheta KL
Where else could you see all these old electrical boxes?

Although we are hopefully still very far from that scenario, it is fairly clear that similar levels of trust are required for our society to function well too. For our society to flourish, these same standards of integrity are required of our press (and indeed of ourselves if we publish – or share – articles online). The perception that our society is moving into an era where fake news is as valid as proper investigative journalism has led to some calling ours a “post-truth” era. However, as Emmi Itäranta has argued, we should endeavour to avoid calling our times “post-truth”, in part because the term itself is not neutral. Our words and language matter and when we use the term we contribute to the idea that truth is no longer meaningful.

Such thoughts remind us of our own responsibility and contributions to society. If we don’t want fake news to influence politics, we need to be careful what we share or publish online. From our language to our values, we need to behave as if truth matters. And, to me at least, it seems that enjoying a coffee can help us with that. Stopping to appreciate the moment as we savour our well prepared coffee, we can step-back from the “retweet” or “share” button and think, is this evidence based and true or else, what is it that I gain by sharing this?

It strikes me that cafés such as Pulp, with their mix of great coffee and interesting surroundings are perfect spaces in which to slow down and think rather than react and retweet. Perhaps that is what we need for 2017, more time contemplating in cafés, less time on social media. Let’s hope for some quiet time ahead.

Pulp by Papa Palheta is at 29-01 Jalan Riong, Kuala Lumpur, Malaysia,

∗Michael Polanyi “Science, Faith and Society”, Oxford University Press, 1946

 

Categories
Coffee cup science Coffee review Observations Science history

Water wheels and coffee engines at Artisan, East Sheen

Artisan, East Sheen LaneArtisan, on East Sheen Lane, is one café in a small chain of coffee shops in West London (four cafés at the time of writing). Although there was plenty of seating inside, most tables were already taken when I arrived shortly after lunch suggesting that this is a very popular local café. There are many details to notice in this friendly corner shop coffee house. Firstly, the counter, on the left as you enter, was decorated as if supported by a door fixed on its side, one of many quirky features. When it arrived, my black Americano came with a most fantastic crema on top which cracked to reveal the coffee beneath, appearing as if it were a meandering river. Adjacent to my table was a sliding door, presumably leading to the toilets, that had a counterweight hanging from its side, I’m sure that could have led to a series of thoughts on Greek science and Archimedes.

There was also plenty to notice on the counter itself, a sign for two tip jars suggested you either tipped in one or the other depending on whether you wanted to “see into the future” or to “change the past”. As with previous ‘honesty box’ type experiments, it would be fascinating to know which box gets more coins and whether this correlated with external events in the East Sheen area and around. Still, I digress. Also on the counter was a wheel, a bit like the wheel of the Wheel of Fortune TV show. In this café, the wheel offered different coffees or cakes rather than prizes. As the wheel is spun, it is slowed by friction acting against pins that stick out from the circumference of the wheel. When learning about angular momentum and wheels in physics we always assume the ideal of a frictionless wheel without losses. We assume that it spins forever. The wheel in Artisan was quite far from this ideal, the whole idea being that the friction eventually stops the wheel and the pin points to your ‘prize’. So how do we reconcile these two ideas of the wheel? How efficient can water wheels be? And how efficient can engines be?

counter held up by sideways door
The counter and wheel at Artisan, East Sheen

This was a question that occupied Sadi Carnot (1796-1832) (named after the Persian poet Sa’di of Shiraz). Carnot was interested in how to optimise steam engines. Although steam engines were being engineered to be increasingly efficient, Carnot realised that people still did not understand what the maximum efficiency of a steam engine could be. Carnot worked on the principle that heat was a fluid (caloric) and so steam engines could be understood analogously to water wheels. Even though we no longer have this understanding of heat, Carnot’s ideal engine is still relevant for today. He discovered that, for an ideal engine (that is an engine that works without frictional losses etc.), the maximum amount of work that you could extract from the engine depended only on the temperature difference between the maximum working temperature and ambient temperature of the engine (not on the details of the engine such as whether it used steam as its working fluid). In practise this means that a steam turbine (which operates between approximately 543 °C = 816 Kelvin and 23 ºC = 296 Kelvin) has a maximum efficiency of 64%. Were you able to design a frictionless engine made from a cup of coffee (typical drinking temperature 60 °C = 333 K), it would have a maximum efficiency of around 10%

Coffee at Artisan East Sheen
A meandering coffee river and Physics World (November 2016)

Of course, a real engine made from a cup of coffee would encounter frictional losses etc. which would reduce its efficiency. So while we may think that an efficiency of around 10% is not that bad (particularly if we’re making the coffee anyway), once we’ve allowed reality to enter into our calculations, the actual efficiency is much lower. This is probably best summarised as: The best use of coffee is in drinking it, and where better than Artisan coffee if you find yourself in East Sheen (or Putney, Stamford Brook or Ealing)?

Artisan Coffee is at 139 East Sheen Lane, SW14 8LR

 

Categories
Allergy friendly cafe with good nut knowledge Coffee review Home experiments Observations Science history

Bend it like sugar at Muni, Fulham Road

Muni Coffee, near Chelsea and Westminster hospital
Muni Coffee on Fulham Road

The area around Fulham Road and Chelsea & Westminster hospital is one that has long been fairly empty of speciality coffee establishments. Then, in June this year, Muni opened up on Fulham Road (just over 200 m from the main entrance of the hospital, in case you are visiting and looking for a good café nearby). Muni’s website emphasises its social mission, knowing the farmers they trade with by name and introducing Filipino coffee to the UK. Inside, there are plenty of tables (with more outside if you are visiting in warmer times). There is a menu on the wall behind the counter to your right as you enter, but I missed the listing of the Pandan iced tea (which would have been very interesting to try) as I was obviously not paying enough attention and instead opted for my default trying-a-new-cafe coffee, a black Americano.

My sometimes companion in these reviews had a soya hot chocolate while I was very confident to enjoy one of the (lovely) salted caramel brownies because Muni lists all the ingredients for all of their cakes on a tablet device at the counter and so I was encouraged to double-check the ingredients list to see that there was nothing vaguely nut-related in it. A very good feature and this cafe definitely gets a tick in the “cafes with good nut knowledge” category on the right (as well as the new allergy-friendly category). As mentioned, the coffee is imported directly from the farmers in the Philippines, and roasted by Muni in North London. The black Americano I tried was fruity and flavoursome, while the beans I purchased and prepared later using a V60 produced a sweet and floral brew, perhaps with blueberry notes (but with no tasting notes on the packet, I’d be interested to see if others agree with me on this, please let me know in the comments section below).

coffee cake Muni
Coffee and nut-free salted caramel brownie at Muni

On the ceiling, wooden beams had cracked and aged creating a lovely aesthetic and taking me on a thought trail that involved aeroplane engines and heat process treatments. But then I noticed something else. As it was getting dark, the cars passing by on the busy Fulham Road were mostly using their headlights and this meant that, every so often, the edges of the windows around the door changed these headlights into a spectrum of colour. Flashes of blue, red and green as each car passed. It reminded me of Newton’s experiments in which he used a prism to first separate sunlight into its various colours before recombining it with another prism into white light. An effect that led me to think about an instrument that has been advertised as a tool to creating better coffee: the coffee refractometer.

Some of the same physics links Newton’s prism with the coffee refractometer. Perhaps you remember “Snell’s law” from school. The equation describes how much deviation light experiences as it passes from one medium (air) to another medium (glass or coffee). Light travels at different speeds through different media and the refractive index can be thought of as an indicator of the degree to which each medium slows down the light.

the door at Muni
The window at the side of the door at Muni. Rainbows of colour were produced by the headlights of cars as they went by.

For the prism, the important detail is that light is composed of many colours (which means in this context, many wavelengths) and not all wavelengths are slowed to the same degree. This means that the refractive index of the glass prism is slightly different for red light than it is for blue. Consequently, the spectrum opens up as the white light travels through the prism.

For the coffee refractometer, the important point is slightly different. Water containing dissolved solids has a slightly different refractive index than pure water. Measuring the deviation of a light beam through a drop of coffee therefore gives an idea of the concentration of “total dissolved solids” and so a guide to the extraction of coffee from the grind that you have achieved. The difference in refractive index is however quite small, if the measurements here can be relied upon, while water has a refractive index of 1.333 (at 20ºC), a well extracted coffee showed a refractive index of 1.335. We can calculate how much difference this makes to the angle that the light is deflected: Assuming light enters the drop at an angle of 30º, the angle that light is refracted in water is 22.03º, while in the coffee it is 22.00º. A small effect that would be quite difficult to measure unless you had a refractometer.

However, there is an ingredient in some people’s coffee that bends light enormously: sugar (though I do hope that no one reading this uses it in the quantities needed for the experiment below). The refractive index of water is very dependent on the total concentration of dissolved sugar it contains. Therefore you can do a really cool experiment in which a sugar solution (which has more concentrated sugar at the bottom than the top) can be seen to bend the path of a laser beam. All the equipment can be easily found at home (or purchased for not too much from hardware/office equipment shops). Let me know if you try the experiment how you get along (and if you decide to try using a refractometer to enhance your coffee brewing experience). The video was shared on youtube by the Amateur Astronomical Spectroscopy group (CAOS).

Muni coffee is at 166 Fulham Road, SW10 9PR. Just around the corner on Drayton Gardens, is the blue plaque for Rosalind Franklin who used to live at an address there.

 

Categories
Coffee cup science Coffee review Observations Science history

Ripples in the Knowledge Quarter at Pattern, Kings Cross

Pattern, coffee, Kings Cross, Kings X
Pattern Coffee, Kings Cross

In 2018, the Institute of Physics will move to Kings Cross and into what is being called the “Knowledge Quarter”, an area incorporating the British Library, the newly opened Francis Crick Institute and the University of the Arts, among others. Coffee houses have, in the past, been integral to the development of knowledge, places where scientists, artists and the generally interested would meet to discuss new ideas or groundbreaking results. So what about the cafés in Kings Cross? Where will tomorrow’s scientists, artists and the generally interested meet?

Knowing that I would be in the Kings Cross area a couple of weeks ago, I looked up the Kings Cross coffee guide by doubleskinnymacchiato and decided, for not-quite-random reasons, to try Pattern on this occasion. I had been forewarned that the first thing that I would notice would be the colourful patterns on the wall. A good call, that was indeed one of the first things you notice as you walk in. Secondly though were the hat-lampshades on the bulbs over the table at the window (visible in the photo on doubleskinnymacchiato’s review). As anyone who has met me in autumn/winter may appreciate, the lampshades immediately made me feel right at home. It was fairly crowded when I arrived in the late-morning and so I shared the bench in the window with a couple of people who seemed to be discussing history/philosophy and how to write properly referenced argumentative essays. The Americano I had ordered was brought over and, slightly self-conscious to photograph it while sharing the table, I just had to enjoy and savour the well made coffee. There is, perhaps, almost too much to notice at Pattern. But something behind me caught my eye, something that connects coffee, patterns and this café: An old style dial telephone, fixed to the counter.

telephone, dial, coffee Kings X
Patterns in the cord, patterns in the telephone. An unusual feature at Pattern, Kings Cross.

Although the history of the invention of the telephone is quite controversial, the bit that reminds me of coffee is not so contentious, it is to do with how the telephone works. Let me explain.

In the gallery the “Information Age” at the Science Museum in London, it is argued that the commercial success of the telephone was driven by the invention of the carbon microphone, simultaneously invented by David Hughes (1831-1900) and Thomas Edison (1847-1931). It is the Edison version that prompts me to think of espresso. Edison’s microphone worked by packing a cylinder of carbon granules between two metal plates. In my mind I think of Edison’s carbon microphone as similar to a perfectly tamped coffee block in a filter basket. In the microphone, one plate was fixed, the other was flexible and acted as a diaphragm. When somebody spoke into the microphone, the diaphragm would vibrate causing the carbon granules to move alternatively closer together and further apart. Carbon conducts electricity and so the resistance of the microphone changed if the carbon granules were closer together or further apart. The sound waves impacting on the diaphragm were being perfectly translated to electric current patterns that could be transmitted through the telephone lines. The packing of the carbon granules would need to be optimum to transmit the sound, just as the pressure used to press the espresso tablet needs to be just right, enough contact between coffee grains to prevent the water flowing straight through without producing a good coffee, but not so much that the water cannot percolate through the coffee tablet and what should be a lovely espresso becomes over extracted. The ground coffee pressed into the filter basket at Pattern must have fitted this optimum density very well. A well poured espresso revealing that they had achieved that optimum balance between compression and space in the espresso tablet. Good coffee, interesting physics, I’m sure the Institute of Physics will be pleased when it eventually moves to its new home with such great coffee neighbours.

IoP poster in Kings Cross
Physics is everywhere! (But coming to Kings Cross)

Although slightly off topic, a cafe-review considering telephones would not be complete without including the story about Erasmus Darwin, the Devil and his “speaking machine”. Erasmus Darwin (1731-1802) was a fairly portly man who worked hard. So it was inconvenient for him to have to go from his study to the kitchen when he wanted something to eat. Being a bit of an inventor, he installed a speaking tube in his home that connected his study to his kitchen. Desmond King-Hele in “Erasmus Darwin, A life of unequalled achievement”* described what happened next:

“One day a local yokel who had arrived with a message for Darwin, was left alone in the kitchen. He was terrified when a sepulchral and authoritative voice from nowhere demanded ‘I want some coals’. Such a request could only come from the Devil, he thought, wishing to stoke up hell’s fires. The man fled and would not come near the house again.”

The poor local may have been bewildered by the number of telephones and ‘voices from nowhere’ that surround us now. If you’re reading this in a café, why not look around you, notice some strange connection (the very lateral ones can be particularly fun to ponder), and then let me know what you have seen. It’s always interesting to hear the science, history and connections that people notice as they sit in cafés around.

Pattern Coffee is at 82 Caledonian Road, N1 9DN

*Desmond King-Hele, “Erasmus Darwin, A life of unequalled achievement” was published by Giles de la Mare Publishers, 1999.

Categories
Coffee review General Observations Science history slow

Science & Religion at Rag & Bone Coffee, Westminster

Rag&Bone, Rag & bone, coffee Victoria, coffee Westminster
Rag & Bone Coffee in front of St Matthew’s Church.

Can a coffee cart provide the time and space for reflection and enjoyment of a coffee just as a sit-down cafe can? In seeking an answer to this question (as well as on a quest to find more great coffee in the Victoria/Westminster area), I turned up at Rag & Bone coffee on Great Peter St. It was quiet when I arrived in the courtyard of St Matthew’s Church, and the barista took time to make me a lovely, fruity and full bodied Americano (with beans roasted by Old Spike Roastery). Obviously, there is no seating around the bar but, the church behind the cart is open everyday and offers a rare quiet spot in Victoria to sit and reflect, should you want to do so, before you buy your coffee of course! Sadly, as this is a cart and not a sit-down cafe, the cups provided are disposable, but there is nothing to stop you taking your keep-cup along in order to enjoy your coffee. Just behind the cart, a crucifix above the door of the church caught my eye. And that got me thinking about something, perhaps slightly tangential to the ordinary cafe-physics reviews of Bean Thinking, why do some people imagine there is a conflict between religion and science?

I could see how there could be a disagreement if a religion took an overly literal interpretation of a text (as can happen with disputes over evolution). Or if someone used science as an argument against ‘belief’ while failing to appreciate that science too is based on belief (albeit beliefs that we are most likely just to assume as facts without questioning: particularly that our world exists and that it can be understood). But outside those extremes, and if we look at the motivations of both religion and science, it is surely that both religion and science aim to discover or value truth. If both sincerely follow that aim there can be no real conflict, for truth cannot contradict itself.

Earth from space, South America, coffee
One planet. One home.
The Blue Marble, Credit, NASA: Image created by Reto Stockli with the help of Alan Nelson, under the leadership of Fritz Hasler

Instead the investigations of one can inform the other and help both to advance our understanding of the world. Take for example the urgent issue of climate change. Scientists, using science as a tool, can investigate and highlight areas of concern for our planet (increasing CO2 levels, rising sea temperatures, a probable increase in extreme weather events, etc) but strictly speaking, as a tool it can go no further. If a scientist then urges us to do something to mitigate climate change, they are not speaking as a ‘scientist’ but as a human being; a human being who is informed by ethical concerns. It would be perfectly logical for someone to recognise that climate change is happening while holding that there is no obligation on our current generation to do anything about it. We may find such an opinion objectionable but that is the crux of it, we have introduced values to the discussion in the form of ‘right and wrong’ and ‘good’. We have moved beyond the remit of science. Religions have had millennia to consider the human condition and what constitutes ‘good’ or ‘right’. For us to combat climate change we need not just the evidence that it is happening, but an idea of a better, or more ‘just’ world. Ethical systems are of course possible without religion, but discussion informed by religious concern can help to change ‘concern for our planet’ into the concern for and protection of ‘our common home‘.

Artemisworks photography, rosary and keyboard
Prayer beads on a keyboard.

Then there is a link between religion and science that brings us right back to Rag & Bone Coffee and St Matthew’s church yard. When St Matthew’s was built back in 1849, the area surrounding it was squalid, conditions were so bad, the area towards Victoria St. was known as the “Devil’s Acre“. The Dean of Westminster, and the new vicar of St Matthew’s recognised that, to help people out of poverty, drastic steps would need to be taken and one of these was to improve education. The Dean of Westminster died soon after St Matthew’s was built but his wife, Mary Buckland, who was also a palaeontologist, wanted to continue his work with the poor. In order to improve the conditions for those living in the slums in the Westminster area, “Mrs Buckland” established a coffee house on Old Pye St, that was cared for by the Revd. Richard Malone, vicar of St Matthew’s. The coffee house was a place where lectures were given and a library was set up. The church and people in the scientific world, worked together to help the poor of the area positively change their living conditions.

The coffee house eventually had to close but, perhaps it could be said that, in a sense, the presence of Rag & Bone coffee in the courtyard of St Matthew’s, continues this work. Although times have changed, and the area is no longer a slum, there is a different form of poverty, people who are time-poor and harassed, working in the offices that now surround the church. In this sense, Rag & Bone Coffee offers not just refreshment, but a brief time-out from the daily grind for the people who now pass by this space. As making coffee is both an art and a science, perhaps we can also say that here too, science and religion work together, with coffee, to make the world a better place.

Rag & Bone Coffee can be found in the courtyard of St Matthew’s Church, Great Peter St. SW1P 2BU.