I spent a Wednesday afternoon at the Intelligentsia RoastingWorks facility enjoying a birthday present I gave to myself: a class offering Barista training. Intelligentsia is one of a few highly renown coffee roasters in the US and their facility — particularly their test kitchen — is the proving ground for many of the people pouring your favorite cup of coffee in shops and restaurants all across the US.
I’m growing really fond of coffee — not just for the caffeine (though I really like that part). I love the way a perfect cup of great coffee explodes in my mouth, filling that space with flavor. The esters giving a “big mouth” feel that hits you immediately with some acidic, citrus tone and finishes as you swallow with a resonant sweetness that is really clean. Coffee has 800 flavor components to it — 400 of them are aromatics. This is the stuff I learned.
Making a good espresso is an exercise in playing within constraints. The water should be right around 200º F. Shot out of a machine at about 600 lbs/sq. in., you will force that water through 18 grams of ground coffee tamped into a typical American filter basket (probably around 14 grams if you’re in Europe) to make a double espresso. You’ll have that water going from anywhere between 23-28 seconds. More than that and the espresso turns to crap. Less than that and the espresso tastes really acidic with none of the sweetness because there isn’t enough heat or time to dissipate the sugars in the coffee grind (acid dissipates faster, so it dissipates first).
The amount of coffee grind to water is important, and there are recognized ratios, where weight is your guide to how well you’re doing at making the espresso:
- Normale ratio is 1:2 – 18g coffee grind, 4oz water leads to 36g coffee.
- Ristretto ratio is 1:1.55 – 18g coffee grind and enough water to lead you to 28g coffee.
- There’s no recognized name for the ratio that Intelligentsia uses (and I liked), but let’s call it Mezzo — this is 1:1.8 – 18g coffee and enough water to get you 32g coffee.
After making probably 15 shots of espresso in a three hour time span that it takes a lot of work and it’s the give in these constraints that, when you play with them, gives you the variation that often leads to crap espresso and, when intuition and competence work together, can lead to mastery. You see, what we look for in the creation of espresso is the weight. If it takes more than 28 seconds to get to that weight, it’s already wrong, and you need to start over. If you get to the desired weight before 23 seconds, it’s already wrong and you need to start over. You need to clean the filter basket well every time you make an espresso. You may need to adjust the grind, even using the same coffee beans from the same lot, brewing one hour to the next. So many other factors in the temperature, the air pressure, the humidity in the room, the heat of the burrs in the grinder, the heat from the espresso machine… these seemingly intangible elements come into play which make automating great espresso impossible.
Now… read what I wrote just now. It’s not that you can’t fully automate making espresso. Clearly one can. I’m going to tell you that having had many a machine-crafted espresso and many a hand-crafted espresso, while the machine will go through the same motions with precision, it will never yield a perfect cup. Humans are prone to fail at that, too… but given competence strengthened by a developed intuition, humans can rock an espresso that is perfection, and when so much coffee is built on getting espresso right, as much as we can allow people to do that well, we have to, but it’s not about the tools — at the end of the day, it’s about the craft.
There are three focus areas to preparing that espresso: dose, tamp and the insert. The dose is how much coffee grind you’ll use, which is 18g. The real coarseness of the grind is adjustable, but the total weight of that coffee grind is consistent.
If you don’t tamp the grind into the filter basket correctly, it’s going to affect how the water hits and works through the filter to make the coffee. With that tamper as an extension of your wrist and thumb, straight through your forearm, you’re going to press the tamper into the basket straight, feeling the pressure into your shoulder and then give a slight twist. Get this wrong and the water won’t distribute evenly.
Coffee beans that are ground for espresso are ground very fine — and that much surface area being exposed to the air — you have very little time to convert that grind into great coffee before the grind itself goes stale. Coffee ground for espresso goes stale in less than 60 seconds. In that time you need to get 18g into the filter basket, tamp it and insert that basket into the machine starting the water not more than two seconds before the residual water in the machine starts to cook the coffee. You start your timer and the water pressure at the same time.
Now… about that cup of coffee I need to make