Reverse engineering espresso

April 30th, 2014

Typically when we think about brewing espresso it all starts with a dose of dry coffee going into a basket. We might start out with our 19g of coffee, and think about what we want to do from there. We might try a ratio that we enjoyed with another coffee, and taste it and measure it and make adjustments from there.

I’m not making a criticism of the way we think – when you make coffee you feel like everything starts with the raw materials, and this isn’t a terrible way to think. At the end of all this you’ll end up with a recipe, but different coffees will need to be treated differently (even if you want to confine them within the same parameters).

Technology exists, however, for us to start to think about it from the end point backwards, to reverse engineer our product. Why does this matter? If we start from the end of the process, we start by clearly defining the customer experience and then using our techniques, equipment and understanding to create and craft that.

This means that we might have to make some pretty critical decisions that aren’t used to making. Let’s start with a topic that’s always a little tricky for us:

How strong should my espresso be?

This is a fun place to start, but it does mean you’ll need some experience in measuring the strength of espresso and have been paying attention enough to know what you like.

As a reference point – I rarely enjoy espressos that exceed 12% strength. At this point the shot certainly have a tonne of texture, but I find the flavours too concentrated to be easily discernible and enjoyable. I really enjoy espresso in the 9–10% range. This is simply my own preference, and by no means a recommendation. Lots of people have strong, positive responses to very strong espressos.

How much espresso do I want to serve?

This feels like a particularly strange question, but it is worth considering. How much liquid do you want to put in a cup? Is 32g of espresso worth the same as 36g of espresso? Either way, for this to work you need to make a decision.

Personally, again all preference, I don’t really want more than 50g as a double – generally I prefer a double to be 36–40g of coffee.

What about extraction?

Enough’s been said about extraction to spare too much in-depth conversation. You like what you like, either as a cafe or a roaster – and certainly as a roaster you should be targeting roasts against a specific level of extraction. I like espresso, from conventional flat burr grinders, at around 20% extraction.

So now I have a recipe. I know I want 40g of coffee, at 9% strength that is a 20% extraction. Fire up VST Coffee Tools and plug it in. By adjusting dry coffee dose until I hit my desired extraction then I can see that for this recipe to work I should start with 18.6g of coffee.

I can then start with 18.6g to 40g and adjust grind until I hit my desired espresso – presuming my water, grinder and baskets allow me to do this. I would pretty much ignore time (though from experience I know it will likely end up in the late 20s/very early 30s). I wouldn’t dial in against time though, I’d be pulling on scales to hit my shot weights.

Is this how I should make all espresso now?

The idea of this post isn’t to change the way you dial in, but instead to present an alternative way to think about how we generate our brew recipes. I think it is pretty healthy to change it up sometimes, to start with what our customer will drink (and how we want that to taste) and to work backwards from there.

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