Categories
Coffee review General Observations slow

2 years in

3D hot chocolate art on an iced chocolate, Mace, Mace KL, dogs in a chocolate
Happy birthday to me

Last weekend, Bean Thinking turned 2. So I’ve been looking back at the cafés I’ve visited over the past two years. Bean Thinking started as a way to slow down and to try to see things in a (slightly) different way, to really enjoy the coffee but also to take time to explore the stories, and the science, that can be found in different cafés. I’ve enjoyed the coffee in each café that I have visited but, as always happens, some stick in the memory a little more than others.

So I decided to pull together five cafés which, for me, had an interesting story to tell or prompted an unexpected chain of thoughts. I have sadly had to leave out some great cafés and some really fun stories (for me to think about at least). However, these five stood out. Each café introduced an unexpected bit of science to me, or had something about them that meant that slowing down and enjoying the coffee provided a really special moment. Consequently, each café features for slightly different reasons, and so rather than create a top 5 (which would be impossible anyway), I have listed them alphabetically. I hope you’ll excuse this trip down memory lane.

Amoret, Hammersmith

Kettle drum at Amoret
Coffee on a drum at Amoret

It is not every day that a well made V60 can transport you to another planet. Yet that is what happened for me at Amoret in Hammersmith. The cylindrical design of the table reminded me of a drum but the question is, why do drums make the sounds that they do? The answer to this question took me on a journey into sounds. Just how different would Bach’s famous fugue sound if played on Venus rather than Earth? And then a surreal moment as a Dutch TV station decided to take Bananarama to Venus courtesy of research conducted at Southampton University. This was all accompanied by great coffee in a very pleasant cafe, the review can be found here.

Coffee Affair, Queenstown Road,

Contemplating the floor at Coffee Affair
Contemplating the floor at Coffee Affair

Where better to slow down and appreciate the moment than a place reminiscent of the geology of the South Downs that helped Charles Darwin to argue the case for his theory of evolution. Coffee Affair occupies the old ticket office at Queenstown Road station. The fixings and the floor of the café reveal evidence of the people who inhabited this space in times past. Watching the V60 being prepared, slowly, carefully, exactly, emphasises this sense of time. The result is great coffee in a place that almost forces you to step out of the speed of modern life and stop, put down the smart phone and take time to just notice. Coffee Affair was reviewed here.

Lumberjack, Camberwell,

Lumberjack coffee Camberwell
Exploring local connections at Lumberjack

There’s a strong emphasis on keeping it local at Lumberjack in Camberwell, as well as a preoccupation with all things wooden (this being an enterprise set up with London Reclaimed). So it was interesting to discover that there was a fairly local connection between Camberwell and the ultimate ‘local’ London tree, the London Plane. Not only that, but research that had been published a few weeks before I went to review Lumberjack had shown that, surprisingly, the wind speed needed to fell a tree was fairly constant at around 56 m/s, irrespective of the size or type of tree. This surprising finding was the cherry on the cake for this ultimate in local reviews (here).

Red Door, Greenwich,

vortices, turbulence, coffee cup physics, coffee cup science
Beautiful physics at Red Door

Just what would happen if you put a cup of coffee on a record player? A turntable in a corner at Red Door in Greenwich meant that not only did I start to think about this question, I decided to start some experiments to find out. The resulting physics was physically as well as scientifically beautiful. The experiments can be done by anybody with equipment that you can probably find at home (though I would recommend not using an actual turntable). It turned out to be an elegant experiment involving vortices, but as Helmholtz noticed, similar vortices form in organ pipes, the atmosphere and even in electromagnetism. Truly a beautiful piece of connected physics that I would have missed had I enjoyed my coffee ‘takeaway’. More here.

The Turkish Deli, Borough Market,

Turkish coffee
The universe in a cup of coffee at The Turkish Deli

“The universe is in a glass of wine” so said a Greek poet according to Richard Feynman, but at the Turkish Deli it is more obvious in a cup of coffee. When made properly, Turkish coffee requires at least four minutes of ‘settling time’ before it can be enjoyed. You could use this time to think about how the concentration of coffee particles changes as a function of the depth. Similar considerations led Jean Perrin to conduct experiments back in 1910 that he declared showed that “… it becomes very difficult to deny the objective reality of molecules” (which before that point had indeed been very much denied). Now that The Turkish Deli also roast and grind their own coffee on-site, there is even more reason to visit and ponder the connectedness of our coffee and our planet. The Turkish Deli was reviewed here.

With so many more cafés to explore, and things to discover, who knows what the next year or two will bring. And if you’ve got a recommendation or found a great café where you have stopped and noticed something intriguing, no matter how lateral, why not drop me an e-mail, I’d love to hear your experiences of slowing down and appreciating our coffees.

 

Categories
Coffee cup science Observations

Musical Coffee

Tasting notes from Finca San Cayetano coffee
Tasting notes from Hasbean’s Finca San Cayetano coffee

A few weeks ago, I chanced upon an article “Listening to Stars Twinkle” (link) via Mr Gluckin on Twitter. At very nearly the same time, I received in the post, a new coffee from Hasbean (link) which suggested an entertaining coffee (see pic).  A perfect time to have some fun with coffee, I think.

The article was about ‘stellar seismology’: Understanding the inside of a star by watching sound travel through it. We know from daily experience that the way sound travels through air depends on the temperature of the atmosphere.  Sounds can appear to travel further on cold evenings than on warm nights for example (for an explanation of this effect click here). Conventional seismology on earth uses the same principles. By measuring how sound is deflected as it travels through the earth, geologists can work out the type of rock in the interior of the earth (and whether the rock is solid or molten).

Burmese bell, resonating bells, stars
A bell rings with a note that depends on the composition (bronze) and shape of the bell. © Trustees of the British Museum

Unlike these earthly examples though, ‘listening’ to a star is not so easy.  We cannot hear stars vibrate as sound travels through them. We can only view them from a distance.  It is therefore very fortunate that the surface of a star will start to move noticeably as the sound travelling through the star hits one of the star’s ‘resonances’. Just as a bell has a tone depending on its shape and what it is made of, so a star has a series of ‘notes’ that depend on the composition and temperature of the star. These ‘notes’ are the star’s resonances and we can find out what they are by watching the different patterns on the star’s surface. Each resonance has a distinct, signature pattern which is dependent on the ‘tone’ of the resonance, much like the patterns you can see on the surface of a coffee by dragging a take-away cup across a table. The temperature and composition of the interior of the star determine the ‘notes’ of the resonances and so, by looking at the surface vibrate we can work out what is inside a star.

Can we illustrate this with a cup of coffee?  Of course we had fun trying.

In the video, the hot coffee is poured into a take-away cup that I have previously made into a loud speaker.  In the next few days I will upload details of the making of the speaker onto the Daily Grind. Hooking up the speaker to my phone, I could easily play music through the cup (and through the coffee).  But by connecting the cup-speaker to the phone with a tone generator app installed (free and downloadable from the app store for iPhones and probably similar for Android phones) I could generate single ‘notes’ through the speaker from 1Hz to 20 kHz.  Our ears are only sensitive to frequencies from approximately 20 Hz-20 kHz so below 20 Hz we cannot hear the notes being played.

home made loud speaker, coffee cup, kitchen table physics
The coffee cup speaker in an improved design

Nonetheless between 12 and 13 Hz, the surface of the coffee started to show a lot of movement. Although the distinct patterns of a resonance could not be seen (perhaps the speaker, lighting or other experimental conditions needed optimising), we can clearly see the coffee resonate as the surface is vibrating so strongly at these frequencies. As the tone was changed to down to 10Hz or up to 14Hz, the vibrations faded. The ‘resonance’ of the hot coffee filled cup-speaker was 12-13 Hz.  If the cup were to be filled with yoghurt or only half filled, we would expect the ‘note’ at which the surface vibrated to change. Indeed, in this latter case, I could no longer find the resonance anywhere near 12-13 Hz.

‘Listening’ to the coffee by watching its surface means that we can, in principle, work out the properties of the coffee, its temperature, density etc.  And it is in this way that we ‘listen’ to stars ‘twinkle’ so as to understand our universe more.  So thank you MrGluckin and Hasbean for providing an entertaining couple of weeks for me!  Please try this at home and let me know what you discover in the comments section below.

Important Disclaimer: No coffee was wasted in this experiment! I had already finished drinking the contents of the cafetiere and just used the old grounds to provide the ‘coffee’ in the video.

Extra thanks: Becky Ramotowski and Gardensafari.net for the photos. The photos from Garden Safari are © www.gardensafari.net