Categories
General slow

What is a good coffee?

Sun-dog, Sun dog
A photo to suggest happiness? Spotting sun dogs makes me happy.

A few weeks ago, an opinion piece appeared in a UK newspaper with the title “Scientists find nirvana as hard to explain as to attain”. The article was about the launch of a course, endorsed by the Dalai Lama, by the group ‘Action for Happiness‘ and the release that week of the Office of National Statistics League table of personal well-being. While happiness and well-being are both evidently things that we want to encourage, what do we mean by quantifying well-being into a league table?

It seems to be part of what can be a tendency to ‘scientise’ aspects of our lives and experience, aspects that are clearly, when we think about them, not described by science. Coffee is not immune from this. Studies have been made of how we feel about drinking our coffee based on whether we drink coffee for pleasure or for the caffeine kick. Why is it that we feel the need to quantify something in order to demonstrate that we have an understanding of it? Does labelling something as ‘scientific’ give it greater credibility?

As described elsewhere, part of the thinking behind Bean Thinking is to explore the beauty and the connectedness that an appreciation of the science in a coffee cup can give us. But there is an important corollary to this. It is to celebrate the contribution of those other aspects of our thinking that allow us to appreciate beauty: Art, literature, history. Beauty is not a quantity that can be defined scientifically (although we all seem to have a mutual appreciation of beauty and, surprisingly often, of what is beautiful). Happiness is similar. We have an understanding of what happiness is but a quantitative evaluation of happiness eludes us.

good coffee, nun mug, Ritzenhoff
How would you define a good coffee?

In hindsight it seems that, entirely unintentionally, the tagline of Bean Thinking captured both of these aspects of meaning. “Where entertaining science meets good coffee“: Hopefully it is fairly easy to find the science on the website but good coffee? What do we mean by ‘good’. Is my version of “good” coffee the same as yours? Is ‘good’ in this context something that can be quantified (acidity, aroma etc) or something more, a word that incorporates aspects of the living conditions of the farmers who grow the coffee and the workers who pick the cherries at harvest time? In attempting to understand what is a ‘good coffee’ we may be tempted to define good as being a coffee having certain properties, a pH around X, a quantity of caffeine around Y and a fraction of 2-furfurylthiol (a chemical which contributes to coffee’s pleasurable aroma) of at least Z. This is a route that will lead us to instant!

But joking aside, by narrowly defining the word ‘good’ so that we feel that our understanding of it is scientific and therefore irrefutable, we have lost what we originally meant by good. Science is an important tool, one that helps us to understand (and to control) the world around us but it is not a philosophy. We can never use science to define a ‘good coffee’ in a way that we would all recognise as a good definition of good. Of course science can help us to decide aspects of a good coffee (the pH, the caffeine content etc. all contribute to a good cup) but we cannot use it, of itself, to define a good cup. The same must go for happiness and other aspects of our lives (can we measure a good school by its position in a league table for example?). We must always be on our guard against over-stating the proper limits of science. We cannot use it in defence of a metaphysical position. The strength of science lies in its being a key part of our tool box for examining and understanding the world.

Fish in a tank
Fish in a tank

Admitting that aspects of our definition of a good coffee are qualitative, arguable or even “subjective” does not devalue the meaning of the word good. The same applies to happiness and many other areas. Quantifying something can mean that we understand it less. Midgley has an interesting analogy in this context of the roles of different areas of our thought:

“[An image that is helpful] is that of the world as a huge aquarium. We cannot see it as a whole from above, so we peer in at it through a number of small windows. Inside, the lighting is not always good and there are rocks and weeds for the inhabitants to hide in. Is that the same fish coming out that we saw just now over there? And are those things stones or starfish? We can eventually make quite a lot of sense of this habitat if we patiently put together the data from different angles. But if we insist that our own window is the only one worth looking through, we shall not get very far.“*

According to the ‘quantitative’ measurement of well-being in the ONS survey, London is a relatively miserable place. The Action for Happiness group runs a Happy Cafe network which includes two London cafes: The Canvas and The Skittle Alley Coffee & Pantry. I have no idea as to whether such cafes can help us to live happier and more meaningful lives. I do know however that I won’t be able to find out whether they do so ‘scientifically’. I also know, that slowing down and spending five minutes contemplating my coffee, wherever I am, will help me to develop into a more rounded person. I am unable to define (scientifically) what I mean by rounded.

If you have a good definition of good, why not share it in the comments section below. Alternatively, if you are enjoying five minutes (or more) in a great cafe with something about it that is interesting to notice, why not think about writing it as a cafe-physics review?

* “The Myths We Live By”, Mary Midgley, was published by Routledge Classics, 2004

 

 

Categories
Coffee review Coffee Roasters Observations Science history slow

Waiting for a green light at Alchemy, St Pauls

8 Ludgate Broadway, St Pauls
Alchemy Coffee

Alchemy, “a seemingly magical process of transformation, creation or combination”, is certainly a cafe that lives up to the dictionary definition of its name. The branch, on Ludgate Broadway near St Pauls, is the outlet that ‘showcases’ the coffee of Alchemy Roasters. On walking into this cafe, I was presented with a menu of two types of beans for espresso based drinks or two different beans for filter/aeropress. Both sets of coffees came with tasting notes. After a brief chat with the friendly barista I went for the San Sebastian with aeropress. Notes about the origins of the coffee are dotted around this superbly sited cafe (its location is ideal for people watching). The coffee is directly traded (where possible) and, if lattes or cappuccinos are your thing, there are also details about the farm that produces the milk.

Although there were cakes on the counter, I had just had lunch and so had to pass on what looked to be a good selection of edibles. The coffee though was certainly very good and definitely an experience to be savoured. As, perhaps I should have expected, when the coffee arrived it came in a beaker reminiscent of chemistry laboratories. From my chair in the corner, I could watch the preparation of the coffee behind the counter, the people coming into the shop to order their coffee and the crowds passing by outside.

E=mc2 Einstein relativity in a cafe
Scales at Alchemy. Weights on one side, chocolate on the other, it can only mean one thing: energy-mass equivalence

Close to where I was sitting was an old style set of measuring scales. This see-saw balance had weights on one side and chocolate on the other. Perhaps this connection seems tenuous, but for me weights on one side of the scales and an energy bar (chocolate) on the other side could only mean one thing:

E=mc²

The equation relating energy and mass for a particle at rest derived, and made famous by Einstein. The equation comes from Einstein’s theory of special relativity which states that nothing can be accelerated to faster than the speed of light (in a vacuum). First set down in 1905, the theory has some very odd predictions, among which the best known is probably the twin paradox (details here). The idea is that a moving clock will be observed to run slowly by a stationary observer, a prediction that has been confirmed several times by experiments using atomic clocks (here).

San Sebastian via Aeropress
Coffee is served at Alchemy

Moreover, the equation states that mass and energy are equivalent and that a small amount of mass can produce an awful lot of energy, (details here). A detail which will bring this story of a cafe-physics review nicely back to the Alchemy cafe, to London and to the importance of slowing down. The connection is through a set of traffic lights in Bloomsbury. Back in 1933, Leo Szilard was waiting to cross the road at the traffic lights at the intersection of Russell Square with Southampton Row. Szilard had recently escaped from Nazi Germany and was spending his time as a refugee in London pondering different aspects of physics†. That September day, Szilard was thinking about a newspaper article featuring Ernest Rutherford that he had read earlier. In 1901  Ernest Rutherford, together with Frederick Soddy, had discovered that radioactive thorium decayed into radium. The changing of one element into another could be considered a type of modern day alchemy. However Rutherford did not believe that there could ever be a way of harnessing this nuclear energy. In the article read by Szilard in The Times, Rutherford had dismissed any such ideas as “moonshine”. Szilard was forced to pause his walk as he waited for the traffic lights to change. Those few moments of pause must have helped clear Szilard’s mind because as the light went green and Szilard was able to cross the road, a thought hit him: If every neutron hitting an element released two neutrons (as one element was transmuted into another), a chain reaction could be started. As part of the mass of the decaying atom was released as energy, it would mean that, feasibly, we could harness vast amounts of energy; E=mc².

This idea, a consequence of spending five minutes waiting for a traffic light rather than checking Twitter (not yet invented in 1933), proved to underpin both the nuclear fission which we use in electricity generation and the nuclear fission that we’ve used to develop weaponry. It makes me wonder what alchemy we could conjure in our minds if we stopped to enjoy the transformations of the coffee beans at Alchemy.

 

Alchemy (cafe) is at 8 Ludgate Broadway, EC4V 6DU

† A book that some may find entertaining is:

“Hitler’s Scientists”, John Cornwell, Penguin Group publishers, 2003. The book contains this anecdote about Szilard: As Szilard was of Hungarian-Jewish descent, he fled Germany to Britain via Austria on a train a few days after the Reichstag fire of 1933. On the day he left, the train was empty. One day later, the same train was overcrowded and the people leaving Germany were stopped at the border and interrogated.  An event that prompted him, a few years later, to reflect “This just goes to show that if you want to succeed in this world you don’t have to be much cleverer than other people, you just have to be one day earlier than most people.” Something to reflect on in today’s refugee crisis perhaps.

Categories
Coffee Roasters Sustainability/environmental Uncategorized

Plastic, coffee and ethical consumerism

“[W]hile 30% of UK consumers claimed to espouse ethical standards only 3% of purchases examined reflected those standards”∗.

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

Most of us are aware of the growing number of environmental problems facing our planet and many of us want to do something. The question is what? Take the packaging that we use for freshly-roasted coffee. It often comes in metallised plastic bags with aroma valves on the front. Is this packaging good for the environment, or for our coffee?

Many factors will influence our decisions as consumers. Even our ‘ethical’ decisions can be based on different arguments. One factor though is, hopefully, the insights gained from scientific studies on the environmental effects of different types of packaging. Today’s Daily Grind examines some of this science.

Types of coffee packaging available

When you order coffee from a roaster, or buy it at a supermarket, mostly it will arrive in a metallised plastic bag. Some companies will supply coffee in compostable ‘plastic’ packaging, or paper, but most bags are still made from ordinary plastic. Some, larger, coffee roasters supply their coffee in cans. Although these are 100% recyclable, the increased weight compared to plastic packaging and the limited re-usability of the cans mean that plastic packaging can be more environmentally friendly than canned coffee. This article is therefore only going to consider smaller roasters and the plastic vs paper debate.

The problems of packaging

It is helpful to clarify the environmental concerns with respect to packaging. For the case of paper vs plastic, three major areas of concern are:

  • Depletion of a limited resource, recycling and re-usability.
  • Carbon dioxide emissions – in the manufacture and transportation of packaging.
  • Degradability – in both landfill and as litter.

Recycling and the Limited Resource problem

air valve, plastic, environmental coffee packaging
Disposable products make up about 37% of plastics produced‡. Are we wasting limited supplies by wanting our coffee as fresh as possible?

Paper comes from wood but plastics are generally a by-product of the petroleum industry (5% of petroleum in the US is used to produce plastics). Perhaps you will say that not all plastics are made from petroleum by-products. It is true. “Compostable” plastics are typically manufactured from starch based products (corn etc). However other bio-degradable plastics are petroleum based. “Oxo-biodegradable” plastic is ‘ordinary’ plastic with a small amount of catalyst added to it during manufacture. The catalyst causes the plastic to break down more quickly than the conventional plastic without the additive. Typically oxo-biodegradable plastic will be manufactured to degrade after 18 months compared with many years for ‘ordinary’ plastic.

Both compostable and oxo-biodegradable plastic are sometimes called ‘biodegradable’, but there are crucial differences between the two. For the sake of this article, I’ll be comparing ‘ordinary’ plastic with ‘compostable’ plastic (conforming to EN 13432) and oxo-biodegradable plastic (regulation ASTM D6954).

So the first part of the question would be to ask if the coffee packaging is made from recycled material. Paper can clearly be made from recycled material as can ordinary plastic and oxo-biodegradable plastic. Compostable plastic cannot be recycled and so cannot have been made from recycled material.

The second part of the question is whether you can recycle the packaging after using it. Again, paper packaging can obviously be recycled (provided it is not lined with plastic). Although both ordinary and oxo-biodegradable plastic can, in principle, be recycled, the multilayered and metallised design of the coffee bag means that it is not normally recyclable. Some coffee roasters however have started using specially designed plastic packaging that can be recycled in normal recycling centers. It would be great if more followed suit.

Two questions for your coffee supplier: Are the bags used to package the coffee made from recycled material and are they recyclable?

Greenhouse Gas emissions and energy costs

paper bag roasted coffee
Is a paper bag necessarily better for the environment?

Perhaps it is greenhouse gas emissions that concern you and so want to choose an environmentally sound packaging in terms of its CO2 emissions? Paper or plastic? You may be surprised. The environmental cost of a packaging type as measured by its CO2 emissions depends mostly on the energy that is required to manufacture it and the energy that is required to transport the packaging material to the point at which it is used (ie. the delivery of the bags to the roaster).

A few years ago, the Environment Agency performed a lifecycle analysis of different types of shopping bags (plastic, paper, cloth). Plastic bags are typically significantly lighter than the heavier paper bags. So, in addition to the cost of making the bags, it is going to require more energy to transport paper bags to the point of use. The report calculated that the manufacture and transportation of paper bags consumed so much more energy than plastic bags, that paper bags had to be re-used 4 times in order to have the same CO2 emissions as an ordinary supermarket plastic bag, re-used as a bin liner. The situation for a cloth bag was even worse.

Although the plastic used for coffee packaging is much heavier than a standard supermarket shopping bag, the analysis suggests that if your concern is CO2, paper is not necessarily better than plastic. It depends on how you are going to re-use the bags before you eventually recycle them.

Litter and Degradability

I hope that no one is deliberately discarding their used coffee packets onto the street or onto the beach! But litter and bio-degradability are big issues for plastic based packaging materials, particularly at sea. There are horrific stories about marine animals being starved due to consuming plastic or being drowned because they are entangled in it. Paper will degrade very quickly and so clearly does not suffer from the same problems as the plastic packaging in this topic. However, as mentioned above, not all plastic is the same. As well as ordinary plastic, your coffee could come roasted and packaged in a degradable plastic, either compostable or oxo-biodegradable.

sea no litter
There is a big problem with plastic litter ending up in the oceans

The name ‘compostable plastic’ (EN13432) is, to me, a bit disingenuous. It suggests that it breaks down in a composting facility such as my worm bin. But the standard EN13432 does not refer to such home-composting at all. For a plastic to be deemed compostable it has to break down under industrial composting conditions (ie. it is held at 58 C for the period of its degradation). Not all countries/councils offer such facilities for their waste disposal and so a compostable plastic sent to landfill offers little advantage over ‘ordinary’ plastic. However, in the marine environment it has been shown that the compostable plastic bag did degrade quickly relative to ordinary plastic bags‡.

Oxo-biodegradable plastic on the other hand works very differently. At the time of its manufacture, metal-salt catalysts are added to the plastic that determine how long the plastic survives before it breaks down. As long as it is exposed to light and oxygen, the oxo-biodegradable plastic will break down after, typically, 18 months (though the usable time can be made longer than this). Recent studies have shown that it is safe to recycle oxo-biodegradable plastic together with conventional plastic recycling†. Provided that the bag does not get covered in algae, an oxo-biodegradable plastic will break down after 18 months (if that was the time specified at manufacture) whether it is on land or on sea.

Therefore if litter is what you are worried about, you have to ask where you think that the plastics are going to end up and whether you want to be able to recycle them or just re-use them.

So what should you do?

There’s no point me answering this question for you. Ultimately I do not know your individual circumstances and concerns, nor how you are buying and consuming your coffee. Moreover, these considerations have been solely based on some of the environmental problems associated with different packaging. Coffee consumption has other factors, such as the major issue of how the coffee tastes. Earlier this year, Roasting House conducted an experiment to blind-taste the coffee after it had been stored in different types of packaging. You can find the results of that interesting study here.

a take away cup
The next problem. What should we do about take-away cups?

Personally, my concerns are principally the greenhouse gas emissions and the litter/degradability problem. I also buy coffee that is delivered to me very soon after it has been roasted. So I tend to favour packaging that uses unbleached, recycled paper. There is a caveat though. The CO2 emissions caused by paper manufacture and transportation means that I need to find a way to re-use the bags as often as possible before recycling/composting. Fortunately, I think there is a great use for old paper coffee bags: They are the perfect size for carrying loose vegetables or uncooked fish/meat products in supermarkets (rather than use the plastic bags that can be supplied for these products). Each paper coffee bag can be reused multiple times before it finally becomes unusable.

If I were drinking coffee that wasn’t quite so freshly roasted, I would be in favour of using oxo-biodegradable plastic (preferably from recycled material). I do not currently have an opinion on compostable (EN13432) plastic. The results of the degradation of compostable plastic in a marine environment were encouraging and if it starts to become genuinely compostable (as I understand the word in terms of home composting) it would definitely be a type of packaging to consider.

You may come to different conclusions, if you do so, please do let me know what you think in the comments section below. In the meantime, a map of coffee roasters who are trying to improve the environmental footprint of their packaging in a variety of ways can be found here.

 

I am grateful for discussions with Oh Ying Ying of Miracle Spectrum Sdn Bhd who helped me to navigate the minefield of environmental plastics. There is much more to write about plastics, the environment, litter & the Paris meeting, the whole issue of take-away cups for example!

∗ Yeow et al., “Bags for life: the embedding of ethical consumerism” J. Business Ethics, 125, 87 (2014)

‡ O’Brine et al., “Degradation of plastic carrier bags in the marine environment”, Marine Pollution Bulletin, 60, 2279 (2010)

† A report by the Transfer Centre für Kunststofftecknik GmbH (“TCKT”) dated 12 November 2013 on behalf of European Plastic Converters (EuPC), Roediger Agencies.

ª Plastics and the Environment, Ed. AL Andrady, Wiley-Interscience Publications, 2003

Categories
Coffee review Observations Sustainability/environmental

Old and new at Sarnies, Singapore

Sarnies, Telok Ayer St, CBD, Singapore
Sarnies, Singapore

It is just possible that the name ‘Sarnies‘ may suggest a speciality at this cafe in Telok Ayer St. Singapore. And the sandwiches are definitely very good (I happened to visit one lunchtime), but don’t let this deceive you, the coffee is very good too and indeed Sarnies has been listed as one of the top 10 cafes to visit when in Singapore. Sarnies operates from an old style ‘heritage’ building near the central business district in Singapore. This style of “shop-house” used to be ubiquitous in Singapore but as Singapore has developed so the tall buildings of the “CBD” now tower over these remnants of Singapore’s past. The authorities though are keen to preserve their heritage and so many of the buildings have been carefully restored so that the exteriors are fairly faithful to the original. The interior has plenty of table space for you to enjoy your coffee (and sandwich of course) and watch the goings-on around you. Complementary water is available at the bar while you wait for your coffee and sandwich to be brought over to your table.

air vent, natural air circulation, air conditioning
The old air vent system and the new air con unit inside Sarnies in Singapore

Inside, you can see how the demands of modern living have changed the architecture of the shop-house. Above the door, and along the window were a series of vertical timber railings.  These date from the construction of the house and were presumably to assist with air ventilation in a time before air-conditioning. They work because hot air rises and so by putting an opening – a vent – near the ceiling, the  hot air in the building will rise and leave the interior to be replaced by the cooler (it is never cool in Singapore) air from outside. Unfortunately, the temperature in Singapore during the day time is in the 28-33C region and so this method of cooling is not as efficient as air conditioning which is why the vents are now covered in glass. The air-conditioned interior also means that the door of Sarnies is kept closed at all times, ensuring that the air conditioning is as efficient and cool as possible (though seats are available outside should you want to sit in the heat).

coffee at Sarnies Singapore
At the end of the day, it’s all about the coffee

Air conditioning of course needs a lot of energy in order to work. The basics of air conditioning work on the same principles as those that cool your coffee: When a liquid evaporates into a gas it takes energy from its environment and thereby cools it (think about alcohol – or sweat – evaporating from your hand). The issue with air conditioners is that this is a continuous process. The liquid that is evaporated within the air-con unit cooling the room is compressed and re-condensed in the air-con unit outside the shop, in a process that consumes electricity and generates heat which is transferred to the environment outside the shop. The process uses a lot of energy (and therefore generates a lot of carbon dioxide emissions), indeed one organisation in Singapore calculated that more than 60% of their energy consumption on one campus was due to air conditioning.

As cities use a lot of energy, clever design and engineering of the buildings in cities can be used to decrease the carbon dioxide emissions of cities and so help to mitigate the problems of climate change. The C40 is a group of more than 75 of the world’s largest cities that work together to find ways to use urban design to combat environmental problems. Perhaps it is in developing more energy efficient lighting systems or, in the case of the UWCSEA in Singapore, designing their new buildings so that they use air conditioning more efficiently and therefore less wastefully, both in terms of CO2 emissions and in economic terms.

As I was sitting enjoying my Sandwich and coffee in Sarnies, a customer coming into the cafe left the door open. As the hot and humid air started to blow in from outside, the woman sitting near the door closed it to keep the cold in. This small gesture, almost completely opposite to that which I experienced in winter in London last year, helped to ensure that the air conditioning unit did not have to work harder to keep the cafe cool. A small action but one that helps save energy and so the planet, even if just a little bit. If only more of us did this.

Sarnies is at 136 Telok Ayer St. Singapore.

Categories
Coffee review Coffee Roasters General Observations slow

Time for a slow coffee?

enamel mug, teh halia, Straits Times kopitiam
This enamel mug connected glass to the Giants Causeway (Straits Times kopitiam)

Every two weeks, the Daily Grind on Bean Thinking is devoted to what I have called a cafe-physics review. The point of these reviews is to visit a café, slow down and notice what has been going on in a cafe physics-wise. I focus on physics because it is my ‘specialist’ area but the point is to notice the connections between the coffee, or the cafe and the world around us. To see how what is going on in your mug is reflected in the science of the wider universe. Realising that things that seem disparate are in fact connected: It is the same maths that describes electrons moving in a metal and the vibrations on the surface of a cup of coffee. That sort of connection to me is mind boggling. Yet there is more. Thinking about the connections between physics and coffee can lead to meditations on the environment and sustainability, or considerations about how our attitude to drinking coffee changes our perception of it.

Everything is connected.

Parquet floor at Coffee Affair
How many people have walked on this floor? The story of evolution at Coffee Affair

It is my strong belief that whenever we go into a cafe, order a coffee and then proceed to sit down with our smart phones or tablets and check our e-mail or our Twitter accounts we lose a fantastic opportunity. It is the opportunity to be properly present and to notice what is going on around us. It is the opportunity to slow down and to appreciate what life has given us and the surprising things that the world has to offer. To look at the beauty and the complexity of the world and to say ‘wow’.

This appreciation is open to us all, provided we seize the opportunity to slow down and take that time to enjoy our coffee.

So, this week’s Daily Grind is an invitation. It is an invitation open to anyone who sits down with a coffee. If you notice anything peculiar, or interesting, that you feel deserves a mention as a cafe-physics review why not write an edition of the Daily Grind? It does not matter where in the world you are or what your level of science knowledge is. If a full Daily Grind article is too much but you have a great observation, write a paragraph review of your favourite cafe and I’ll add it to the cafe-physics review map. Think that you don’t know enough science? Never mind, share your idea with me and we can work on it together.

Hasten coffee, long black, black coffee, espresso base
Sometimes the link with physics/science is a little bit tenuous, as it was at Espresso Base

Your observations need not be physics-based. It would be great if it is based on some aspect of science, but, as past examples have shown, this link can be a little tenuous if the cafe/subject warrants it.

So, over to you. I hope that someone will respond to this invitation. Please do contact me if you would like to pen a review or if you have any questions. It is my hope that you are all enjoying such great coffee in the huge variety of cafe’s that we now have that there will be plenty of opportunities for people to slow down and to notice and then to share it with the Daily Grind.

Please contact me here, or in the comments section below. I look forward to hearing from you.

 

Some brief guidelines for a cafe-physics review:

1) The cafe should, preferably, be a good independent.

2) Any science/history etc. needs to be verifiable but, as mentioned, if you’ve noticed something great but are unsure of the science, get in touch and we’ll work something out together.

3) If you have noticed something fascinating with your coffee but at home and not in a café, contact me anyway.

4) Please do not write a cafe-physics review of any cafe you are financially associated with. I will have to refuse/delete any ‘reviews’ that I find are adverts.

Categories
cafe with good nut knowledge Coffee review Science history

Gravity and Grace at the Wren cafe

Wren cafe, St Nicholas Cole Abbey
Inside the Wren cafe

There is a lot to like about the Wren cafe. Firstly, there is the space that it occupies (inside St Nicholas Cole Abbey). I went at lunchtime when the way that the light came through the stained glass windows made the cafe a very relaxing and open space. The coffee is from Workshop, complementary water came in 3 flavours (mint, cucumber or lemon) while the food is cooked on site. This is important because it means that they have a great nut policy and could tell me which dishes were likely to contain nuts etc. A further nice feature of the lunch menu at the Wren was that you could select your portion size. Food waste is a major issue for our society and is not helped by the ‘one size’ portions served at many food outlets and cafes. Lunch was offered in two sizes (technically as a side or a main) but the ‘side’ was more than adequate for a mid-week lunch. Sofas in the corner of the room meant that you could relax and take in your surroundings in a comfy environment or, if you were just there for lunch, ordinary chairs and tables were dotted around the room.

Of course, a place such as this will have plenty of things to notice about it. Whether your interest is in architecture or science, there is plenty to observe around you. What I would like to focus on though is a bit of science history that connects the name of this cafe with Isaac Newton, John Theophilus Desaguliers and the dome of St Paul’s Cathedral (which you can see from the front of St. Nicholas Cole Abbey).

View of the Dome from the cafe
The Dome of St Paul’s, visible from the side of the Wren cafe.

Perhaps we all remember the story told to us at school about how Galileo dropped two balls of different mass from the top of the leaning tower of Pisa. According to the story, the balls fell to the earth at the same time, thereby showing that the acceleration due to gravity was independent of the mass of the object and paving the way for Newton’s theory of gravity. Sadly, it seems that Galileo may never have actually performed the experiment (even if it was “re-created” in 2009). However there is evidence that Isaac Newton did perform exactly this experiment in 1710 from the dome of the soon-to-be-completed St Paul’s Cathedral.

“From the top of St Paul’s church in London in June 1710 there were let fall together two glass globes, one full of quick silver [mercury], the other of air”¹. The globes fell 67m before shattering onto the cathedral floor (I’d hate to have written the risk assessment for that experiment). To avoid the possibility of human error, a trap-door mechanism had been designed to ensure that both globes dropped simultaneously. According to the story of Galileo told to us at school, we can calculate how long it would have taken those globes to drop to the floor: 3.7 seconds, independent of mass. So is this what Newton observed? No! The heavy glass globes took 4 seconds to fall, but lighter ones took 8-8.5 seconds! A few years later and Desaguliers repeated the experiment from slightly higher in the dome (but this time with hog’s bladders rather than glass) and obtained the same result.

View of St Paul's Cathedral London
Another view of St Paul’s. Hard to believe that Newton actually dropped liquid mercury from the dome.

This surprising result can be explained when we realise that Newton was investigating not gravity, but air resistance. While the gravitational acceleration is independent of mass, the upwards force due to the air resistance depends primarily on the object’s size (and velocity). This means that the deceleration caused by the air resistance will be different for two globes of the same size but different mass (Force = mass x acceleration). Heavy objects will fall faster in air (until the objects reach their terminal velocity).

There is a certain irony in the fact that this result is opposite to what we feel should happen based on what we learned at school of Galileo’s experiments challenging the scientific orthodoxy of the time. However the result of Newton and Desaguliers’ experiments do not contradict the theory of Newton or Galileo, they just add an extra layer to the problem. We do not exist in a vacuum, we need to think about the air around us too.

Both Newton and Desaguliers were regular coffee drinkers albeit at different coffee houses. Desaguliers frequented the Bedford Coffee House in the north east corner of Covent Garden while Newton regularly retired to the Grecian in Devereux Court (just off Fleet Street). Coffee houses were places that the latest science, politics or philosophy were discussed and debated. The Wren describes itself on its website as existing to “serve the ministry of St Nick’s talks“. Sadly I experienced no discussion or debate on my visit (just a very nice, but solitary, lunch and good coffee) but it is interesting to see the tradition of the 17-18th century coffee houses continued in this Wren designed church and cafe.

The Wren cafe can be found inside St Nicholas Cole Abbey, 114 Queen Victoria St. EC4V 7BJ

[1] The Dawn of Fluid Dynamics, Michael Eckert, Wiley-VCH (2006)

Coffee house info: London Coffee Houses by Bryant Lillywhite (pub. 1963)

Categories
Coffee cup science General Observations slow Tea

What haloes and crowns reveal about your coffee

Coffee Corona
Look carefully around the reflected white light. Do you see the rainbow like pattern?

Several weeks ago I had been enjoying some very good black coffee at OJO in Bangsar, KL. As is fairly typical for me, I had been trying to observe the white mists that form just above the coffee. White mists are fascinating, tissue-like clouds that you can often see hovering above the coffee. They form, tear suddenly and then reform into a slightly different pattern. As I was photographing my coffee, I noticed what seemed to be interference patterns on the mists (see picture), just like oil on water, a rainbow-like shimmering over the coffee surface. Yet that explanation did not make sense; interference patterns form because the layer of oil on water has approximately the same thickness as the wavelength of visible light (see more info here). The water droplets that make up the white mists are a good 15 times thicker than the wavelength of light. It is not possible that these mists are producing interference effects, it has to be something else.

Then, last week and back in London, I was walking towards the setting Sun one evening when I saw what looked like a rainbow in a cloud. What caused this and how was it related to what I had seen earlier in my coffee? A short trip to the library later and it was confirmed. What I had seen in the clouds was most likely a Sun-dog. Formed by the refraction of sunlight by ice crystals in the atmosphere, Sun-dogs manifest as bright regions of rainbow. The Sun-dog appeared in cirrus clouds because these are made from the sort of ice crystals that produce brilliant Sun-dogs. These ice crystals are flat and hexagonal so they refract sunlight exactly as does a prism. Just like a prism, red light and blue light will be refracted by differing amounts and so they will appear at different places in the sky. The minimum angle of refraction produces the most intense colouration and, for hexagonal platelets of ice, this occurs at 22º away from the light source.

Sun-dog, Sun dog
A Sun-dog in the clouds to the right of the setting Sun

I do not find degrees a particularly helpful way of thinking about distance but what helped me is that, in terms of the sky, if you hold your outstretched hand out at arms length, the distance from your thumb to the tip of your finger is, approximately, 22º. Hence, if you see a halo around the Sun at about that distance, it is most likely a refraction effect due to ice crystals in the sky and if you see an intense rainbow roughly parallel to the elevation of the Sun, it is very likely to be a Sun-dog.

What does this tell us about the colours in the mists above the coffee? Well, clearly the mists are not made of ice crystals but neither is the ‘rainbow’ colouring as far as 22º from the light source (a light bulb reflected in the coffee). Also, the rainbow is less vivid and, if you look closely, inverted from the rainbow in the clouds. In the cloud, the inner edge of the arc was red and the outer edge blue, in the coffee, the outer edge is more reddish, while the inner is more blue-ish. This is another clue. On the same evening as I had seen the Sun-dog, there was a full moon and around the Moon was a glowing ring, tinged slightly reddish on the outside. The ring was far closer to the Moon than the Sun-dog had been to the Sun. This Moon-ring, and the coffee colouring are the same effect, they are examples of ‘corona’ (literally crown) and they are caused by diffraction of light rather than refraction.

straw, water, glass
It is refraction that makes the straw appear broken in this glass of water.

Refraction we are all quite familiar with, it is the bending of a straw in a glass of water as you look through the glass. Diffraction is a little more tricky, but it is a consequence of how the light moves past an object. It can be understood by thinking about how water waves pass objects in a stream (or by playing with the simulation here). The amount that the wave is diffracted depends on both the size of the object and the wavelength of the wave. As blue light has a much shorter wavelength than red light, the blue will be diffracted by a different amount to the red. If the objects diffracting the light are of a similar size (as water droplets in white mists are going to be) a spectrum, or a rainbow of colour will appear around the light source. The more uniform the droplet size, the more vivid the spectrum in the corona. The thin cloud around the Moon that evening was made up of many different sized droplets and so the rainbow effect was very subtle. In contrast, around the reflection of the light bulb in the coffee, the water droplets in the white mist are a fairly similar size and so the spectrum is more vividly seen.

Seeing rainbow effects in the sky (or in the coffee) therefore gives us many clues as to what is in the sky or indeed, levitating above the coffee. Please do send me any pictures you have of coronae around light source reflections in your coffee, or indeed sun dogs if you are fortunate enough to see them*.

* Sun dogs are in fact apparently fairly common, it is more that we have to be attentive to see them.

Categories
Coffee review General Observations Science history

Can you see me? At 123 Gasing, KL

Coffee at 123 Gasing
Latte, Long black and chocolate muffin at 123 Gasing, PJ, KL

There are times when you can sit and observe things for quite a while before noticing the physics that becomes a cafe-physics review. There are other occasions when the subject of the review is staring you in the face indeed, it is practically there written for you, on a noticeboard in black and white. Such was the case at 123 Gasing, a cosy and quirkily decorated cafe located, strangely enough at 123 Jalan Gasing (ie. Gasing Road), in PJ, Kuala Lumpur. We enjoyed a lovely breakfast of scrambled egg, long black and a latte (along with a very rich chocolate muffin). The coffee is from Degayo (according to Malaysian Flavours) which means that it is practically a local food product (originating as it does from neighbouring Indonesia). Coffee with minimal ‘food miles’. The only point of regret about our time at 123 Gasing was that we didn’t manage to spend longer there.

decoration at 123 Gasing
Birds on the wall at 123 Gasing.

It is the decoration that strikes you as you look around this cafe. A couple of painted birds sit on top of an electrical wire, prompting the question “why do birds not get electrocuted when they sit on a wire?”. Another question painted to a notice board on the wall asks “what is it that we need that we cannot see or feel?” (answer at the end of this post). Yet it was another thought on another noticeboard that prompted this cafe physics review. That thought suggested invisibility (see picture below).

The idea of invisibility has fascinated story tellers and philosophers for millennia. Trying to render objects invisible is, understandably, very desirable for the military and the defence industry. Although we have always had access to camouflage and deception, it is only relatively recently that it has become feasible to talk about invisibility cloaks as a real possibility.

A sign at 123 Gasing
Am I invisible?

What has moved “invisibility cloaks” into the realm of reality has been the advent of a field called “metamaterials”. As the name suggests, metamaterials are not materials that occur naturally but materials that we manufacture. Combinations of different materials or repeating patterns of a specific material that interact with light in a way that the material itself would not do. The classic example is a so-called split-ring resonator (SRR). These are rings (that were first made with copper) which have a slice cut out of them. Many such rings are arranged in a repeating, lattice pattern. Due to the engineered pattern of the copper, these lattices interact with light in a way that ordinary copper does not (for details click here). Specifically metamaterials can be engineered to bend light around objects so that it appears that the object is not there.

In order to work, the artificial structures (e.g. the copper rings) must be smaller than the wavelength of light that is to be ‘bent’. This means that microwaves (which have a wavelength ranging from a few cm to a few m) can be manipulated far more easily than visible light (with a maximum wavelength of 700 nm, or about 1/100th of the size of a grain of espresso grind). At first sight this may seem disappointing until we remember that even devices that only work with microwaves would have a clear application for the defence industry (radar).

already disturbed
Hopefully not a comment on current scientific funding

There are many ethical and philosophical questions that follow from the fact that it is now within our reach to render some objects invisible. It is not a scientific question as to whether we should do it, the scientific question is whether we can. Where science and ethics collide though is in the funding issue. A subject such as this with obvious applications receives far more funding than fields that advance our understanding but do not enhance our weaponry. Indeed, one of the researchers involved in this field describes how he was “offered large sums of money (almost on the spot)” when he spoke of the potentials of the “Harry Potter project”¹. Something that is alien to those of us who work in less fashionable subject areas where funding is a constant struggle. Government funded science quickly becomes dominated by a quest for application and technology. In effect we bypass the ethical questions of whether we should do this because it is this that will get funded. Science that is not driven by obvious applications will not get funded.

Is this what we want? Should the humanities and philosophy play a role in helping to determine what research is beneficial for society and so which research receives funding? Should ethical considerations play a part in funding considerations, or should scientific research all be about the devices that we can use? It is certainly something to ponder while sipping on our long blacks.

Answer to the question “what is it that we need that we cannot see or feel? Answer in 1990 – Air, answer in 2000 – Wi-fi (though personally I think maybe this should be the answer in 2015, the given answer of “2000” was still a bit early for widespread wifi).

Further reading and [1]: “The Physics of Invisibility” Martin Beech, New York, Springer, 2012

Categories
General Home experiments Observations Science history Tea Uncategorized

Predicting the weather with a cup of coffee?

What do the bubbles on the surface of your coffee tell you about the weather?

weather, bubbles, coffee, coffee physics, weather prediction, meteorology
There is a lot of physics going on with the bubbles on this coffee, but can they be used to predict the weather?

You have just poured a cup of freshly brewed coffee into your favourite mug and watched as bubbles on the surface collect in the middle of the cup. It occurs to you that it is going to be a good day, but is that because you are enjoying your coffee or because of the position of the bubbles?

There are a large number of sayings about the weather in the English language. Some of the sayings have a basis in fact, for example the famous “red sky at night, shepherd’s delight, red sky in the morning, shepherd’s warning“. Others though seem to verge on the superstitious (“If in autumn cows lie on their right sides the winter will be severe; if on their left sides, it will be mild”), or unlikely (“As August, so the next February”).  In 1869, Richard Inwards published a collection of sayings about the weather. “Weather Lore” has since undergone several new editions and remains in print although Inwards himself died in 1937. Amongst the sayings contained in the book is one about coffee:

“When the bubbles of coffee collect in the centre of the cup, expect fair weather. When they adhere to the cup forming a ring, expect rain. If they separate without assuming any fixed position, expect changeable weather.“

A quick search on the internet shows that this example of weather lore is still circulated, there is even a ‘theory‘ as to why it should be true. But is it true or is it just an old wives’ tale? Although I have consumed a lot of coffee I have never undertaken enough of a statistical study to find out if there could be an element of truth in this particular saying. The number of bubbles on the surface of the coffee is going to depend, amongst other things, on the type of coffee, the freshness of the roast and the speed at which you poured it. While the position of the bubbles will depend on how you poured the coffee into the mug, the surface tension in the coffee and the temperature. It would appear that there are too many variables to easily do a study and furthermore that the mechanism by which coffee could work as a weather indicator is unclear. It is tempting to write off this particular ‘lore’ as just another superstition but before we do that, it is worth revisiting another old wives tale which involves Kepler, Galileo, the Moon and the tides.

tides, old wives legends, Kepler, Galileo, Lindisfarne, bubbles in coffee
The pilgrim path between Lindisfarne and the mainland that emerges at low tide is marked by sticks. But what causes the tides?

Back in the mid-17th century, Newton’s theory of universal gravitation had not yet been published. It was increasingly clear that the Earth orbited around the Sun and that the Moon orbited around the Earth, but why exactly did they do that? Gilbert’s 1600 work De Magnete (about electricity and magnetism) had revealed what seemed to be an “action at a distance”. Yet the scientific thought of the day, still considerably influenced by Aristotelianism, believed that an object could only exert a force on another object if it was somehow in contact with it. There was no room for the heavenly bodies to exert a force on things that were found on the Earth. Indeed, when Kepler suggested that the Moon somehow influenced the tides on the Earth (as we now know that it does), Galileo reproached him for believing “old wives’ tales”: We should not have to rely on some ‘magical attraction’ between the moon and the water to explain the tides!

The point of this anecdote is not to suggest that a cup of coffee can indeed predict the weather. The point is that sometimes we should be a little bit more circumspect before stating categorically that something is true or false when that statement is based, in reality, purely on what we believe we know about the world. We should always be open to asking questions about what we see in our daily life and how it relates to the world around us. It will of course be hard to do a proper statistical study of whether the bubbles go to the edge or stay in the centre depending on the weather (whilst keeping everything constant). Still, there are a lot of people who drink a lot of coffee and this seems to me to offer a good excuse to drink more, so perhaps you have some comments to make on this? Can a cup of coffee predict the weather? Let me know what you think in the comments section below.

 

Weather legends taken from “Weather Lore”, Richard Inwards, Revised & Edited by EL Hawke, Rider and Company publishers, 1950

Galileo/Kepler anecdote from “History and Philosophy of Science”, LWH Hull, Longmans, Green and Co. 1959

Categories
Coffee review Observations Science history slow Sustainability/environmental

In the Greenhouse at CoffeeGeek

Coffee Geek and Friends, Coffee Victoria
Coffee Geek and Friends

Earlier this year, a new café opened up in Victoria. Coffee Geek and Friends is located at the far end of Cardinal Place as you enter from Victoria Street. Cardinal Place is an odd sort of shopping centre, a small collection of shops with a glass roof. The building site near Coffee Geek as well as the constant stream of people rushing to and fro make Coffee Geek an ideal place to spend some time watching the world go by. Coffee is by Allpress espresso and is served in very individual mugs. Apparently there is a range of geek-ery in the cafe including a ‘centre piece’ water filter but I admit I missed that as I was too focussed on my coffee. Coffee Geek and Friends is definitely a cafe to keep in mind (along with Irish & June’s) if you need a good place to meet near Victoria Station.

It was a very humid day when I enjoyed my coffee at Coffee Geek and, because the mug had not been pre-warmed before my Americano/long black (my notes don’t specify which) was poured into it, condensation quickly formed around the rim of the mug. The condensation forms for the same reason that dew forms after a cool night: the vapour pressure of the water above the coffee (or the ground) has reached the dew point at the temperature of the mug. The lower the temperature, the lower the vapour pressure has to be for the water in the atmosphere to start condensing into liquid droplets. Hence you will often find that your coffee is more ‘steamy’ on a winter’s, rather than a summer’s day.

Condensation on mug in CGaF
Look carefully at the rim of the mug. Do you see the condensation?

Just over two hundred years ago, William Charles Wells made a study of dew. He observed the weather conditions under which dew formed. He observed on which surfaces dew collected. He noted whether the dew formed on space facing surfaces or ground facing surfaces. After several years of careful study he published his “Essay on Dew” in 1814. His work, showed that the earth radiated heat at night (when it was not being kept warm by the Sun) and therefore that space was cold. Cloud cover reduced the amount by which the ground cooled which implied that cloud cover was acting as a type of blanket for the Earth, keeping the heat trapped inside. Later calculations of the balance between the heat radiated by the Earth and the heat received by the Sun confirmed that, without some heat getting trapped by clouds and ‘greenhouse’ gases in the atmosphere, the earth would be a good 30 C cooler than it is observed to be. Although these calculations are just rough, “back of the envelope” figures, detailed calculations confirm that the Earth is in a delicate balance, heated by the Sun, cooled by radiation and kept warm (and live-able) by a layer of natural greenhouse gases. This “natural greenhouse effect” has been necessary for our development, the problem is that now we are adding yet more greenhouse gases to the atmosphere which threatens to tip the established delicate balance by a few degrees.

Cardinal Place roof, greenhouse
The roof of Cardinal Place shopping centre. A very appropriate place for a meditation on the greenhouse effect

What we now call the greenhouse effect are these extra gases, which are more efficient at trapping heat within our atmosphere. If you can imagine what has been happening over the past three hundred years or so as we have been pumping yet more of these gases into the atmosphere at an accelerated rate, we are in danger of tipping this delicate balance towards further heating of the earth. The 2015 Paris Climate Conference is being held with the aim of requiring all nations to agree to a legally binding commitment to reduce the amount of extra greenhouse gases that we emit to a level that will only result in a temperature increase of 2C. To achieve this requires all of us to work together to reduce our own ‘carbon footprint’. Each of us will have to find our own, individual ways to reduce our emissions but perhaps when we look at the condensation on the rim of our coffee cup, we could remember William Charles Wells and his essay on dew and just think, what can I do, at this moment, to reduce my carbon footprint? Maybe it could be something as simple as turning off that phone (to conserve the battery) and watching what is going on in a café instead. A small gesture but one that would be good for us as well as the earth.

Coffee Geek and Friends is at the northern end of Cardinal Place shopping centre (opposite Westminster Cathedral).

As a Coffee Geek note, I would like to just comment that my notes on Coffee Geek and Friends were written using a “linux-sure” ball point pen. Not particularly environmentally friendly but definitely quite geeky.