Here’s a little sequence I like to call ‘The Downward Spiral of Death’. We’ll start off with a closed loop where it’s just the Barista not measuring the extraction yield of the coffee, and instead relying only on his/her palate (I’m guilty of this one many times).

1. Make an espresso. It’s bitter, ‘roasty’ and lacks body.
2. Increase the dose/pull a shorter shot (this will increase strength and decrease extraction yield).
3. It’s stronger, less roasty and displays more intense acidity than it did before.
4. ‘More body, less roast and more acidity? I’m awesome!’
5. Reside in blissful ignorance.

The problem with this solution is that the barista was

A. mistaking ‘body’ for an increase in Total Dissolved Solids. TDS is purely the strength of the beverage, and is not a good indicator of whether a coffee has a good body or not. When roasted and extracted well, almost all coffees have plenty of body.

B. only perceiving less ‘roast’ flavours because of the higher strength and lower extraction. The fact remains that the coffee was roasted poorly. The barista was merely sweeping that fact under the rug by extracting less from the coffee and increasing the TDS, which reduces our tongue’s sensitivity to flavours such as roast faults.

C. mistaking sourness for acidity. Sourness is most definitely not the same as acidity. It is a fault, in this scenario, stemming from under-extraction and is not an indication of a coffee’s natural flavour. Every coffee in the world can taste sour when under-extracted; only the best coffees, extracted well, will display intricate and defined acidity.

If the barista was to measure the extraction of that coffee, he/she might find that the first shot was well extracted, and the second shot was under-extracted and too strong. This immediately points the finger of blame at the roaster, who isn’t roasting coffee that’s applicable for a good extraction and palatable strength. In an ideal world, the roaster would then start to roast differently, removing the roasty/ashy flavours but still developing the roast to an acceptable degree.

Measuring extraction gives you solid numbers to work with and allows your palate to be more definitive than before. I could and should write an article on every benefit of measuring extraction, but I fear VST wouldn’t be able to keep up with demand afterwards. 🙂

If a Roaster is involved in this Downward Spiral, then it can be much more damaging. The picture below shows an extra few steps where the Barista/Roaster changes the roast because of their incorrect conclusions. This spiral works in both directions, but this darker/under-extract spiral is the most common.

Now, see what happens when you start using a refractometer.

The Upward Spiral of Happiness occurs when the Barista/Roaster realises the coffee became less soluble, and adjusts accordingly. Peace, harmony and balance ensue. Bonus: No one in the roastery is freaking out, and your workplace becomes much happier.

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