Posts Tagged ‘crema’

Video 5 – The return of the absurd

Friday, July 10th, 2009

So to wrap up my first successful week (which has been both harder and easier than I imagined):

Related links:

Previous Absurd Latte Art Challenge

Prizes:

12 Month Subscription – Square Mile Coffee Roasters

12 Month Subscription – Transcend Coffee Roasters

(Update: Thanks to Poul Mark for his generous offer of coffee from Transcend!  Awesome!)

If you are up to the challenge post a link to your work in the comments – I will accept photos or video.  C’mon!  Have a go!  It’s very silly…..

Video 1 – Crema

Monday, July 6th, 2009

Episode links:

Coffeegeek article on crema

Coffee Collective Blog post

The Coffee Collective

Using a lever machine

Tuesday, June 2nd, 2009
lever-texture

These last few days have been a pleasant, but steep learning curve.  I know I’ve muttered about pressure profiling from time to time, but I hadn’t really played with a lever machine properly until Gwilym’s WBC prize arrived. 1
(more…)

Footnotes:
  1. Yes, we kindly offered to ‘look after’ it for him for now… []

Crema and the laws of physics

Saturday, August 9th, 2008

It took me a while to notice that one of the prettiest things about espresso was a little bit confusing.

Watch this video and perhaps you will see what I mean:

In theory it doesn’t make sense. The bubbles contain CO2, which is much less dense than coffee so they should be rising quite quickly and not falling. What would make a bubble sink instead of float? You’ll see the same thing happening if you watch a pint of Guinness settle out – and it was their research that gave me the answer to this question.

What is happening is that plenty of bubbles of crema are rising, but they are rising predominantly in the middle of the shot glass and the pressure they create as they rapidly rise effectively sucks down the smaller bubbles close to the walls of the glass. There is nice explanation of Guinness here (with pictures!)

Another mystery solved…..