Cupping: From Raw to Ready

November 17th, 2010

Today at the roastery we had a very interesting cupping. We had pulled out a sample from the roast every minute, starting five minutes in and ending at around 15 minutes. This is not a particularly new idea – full credit to Tom at Sweet Marias. His video of it here is worth watching, especially as I am not really going to talk too much about how each bowl tasted.

I didn’t expect to find some stages of coffee roasting to produce such unpleasant effects, or flavours in the cup. Just sniffing the cupping bowls was enough to put me off! Hard to describe, and once water hits it is very different to the aromas you’ll get when using the trier during the roast.

I think it is definitely a worthwhile experience. The only word of caution for those thinking about it is to do with grinding raw/barely roasted coffee. It is incredibly tough stuff, and I was glad to have a VTA6 running full speed to drop the coffee into!

I posted about the little experiment online and got an interesting tweet in response. I had a spare moment this evening, so I went upstairs and rebrewed everything to see what the numbers would say.

Each bowl was done at 60g/l and had the same grind and steep time. I then poured each bowl (rather messily I might add) through a dry v60 paper into another bowl to let it cool. (There is a certain joy in making an absolute mess doing this stuff, knowing there is no one to tell you off!)

I then measured each one in the Extract Mojo. A few very important points before we look at the graph. This is based on a single cupping bowl, and a single experiment. There is plenty of room for error here. Secondly – the refractometer measures the liquid’s refractive index. Software is required to convert this to a strength of coffee liquid. That software has not been created to do accurate calculations for green/barely roasted coffee so the data shouldn’t be considered accurate. (This should be considered no more serious than Tim and I experimenting with the K-ONE written up here!)

Also – I spilled a lot!

Even so – we get an interesting line:

Extraction in a cupping bowl versus roast time

I should add that the numbers (in terms of time) are not accurate and the final sample is more than a minute ahead of the one before it, perhaps explaining the leap. First crack is evident in the jump at around 11 minutes (I realise now this is actually 12 minutes as we’re missing a sample from earlier on – apologies!)

I haven’t tried this particular product (Nescafe Green blend), but having done this cupping today I am fairly sure that Nescafe may well have created something even more disgusting than their regular instant coffee. Impressive work….

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