It was once said that making a great cup of coffee is an art, doing it repetitively day in and day out is a science. Homogeneity is the goal.
In my previous posts I explored the differences in manual and electronic dosing grinders—the pros and cons for each and where I feel the technology should be headed in the future. So it raises some questions: how do you work with the existing equipment, and what is the correct way to work with it?
The simple answer is you work with what you’ve got and what you know.
I’ve taken a hybrid approach that enables the team here at Coffee On Cue to achieve consistency in each cup regardless of which barista is on the machine. Hybrid? Yes, Hybrid.
Today all but one of our coffee carts have electronic grinders equipped. I’ve done this for a few reasons, most of which are clear in my previous posts. However to recap;
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They’re far more accurate
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There’s less wastage
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There’s less chance of RSI for the barista
In saying that , I don’t think that it’s good enough to set a dose to an amount of time, hold the group handle underneath the grinder and just wait for a dose to come out expecting that the coffee “should just look good” when we know that electronic grinders don’t actually dose a consistent amount of grams of coffee per dose.
When just using an electronic grinder, somehow you need to calibrate:
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Grinder dose in seconds
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Espresso programming of shots in a volume of water
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Yield (your final espresso shot) in millilitres
This is a conundrum…
Here’s our hybrid solution based on weight and time;
We simplify the process to 3 variables that guarantee consistency of brewing in each cup.
1) We weigh in:
Firstly, we still use an electronic grinder but we dose into a cup in order to weigh how much coffee is in our dose. By doing this it takes a few seconds extra, however we achieve the same amount of coffee by weighing then adding or subtracting coffee from our dose. In the case of our La Marzocco GS3s and our La Marzocco Lineas we dose in at 23.5grams.
2) We weigh out the yield:
Secondly, our coffee machine is calibrated to a volume of water. In our case it’s 78 grams of water that passes through the group head. Previously, yield was measured in a shot glass as say 30 millilitres per split shot, 60 in total for a double). Our system of defining yield is built on weight. From the 78 grams that the coffee machine is programmed to produce for the program, we achieve 43-45 grams of espresso per double shot. The difference of the 78 is either dissolved or is exhausted back through the group head of the machine. The net result is 43-45 grams of espresso in total OR 21.5-22.5 grams of espresso for each split shot. We weigh out the yield on a consistent basis to ensure that the program is still relevant to our brew recipe.
3) We time each shot.
Luckily on our La Marzocco machines there is an inbuilt timer. For each extraction of espresso we are aiming for a shot time of 27 seconds. This means that the from the time that the programmed function is activated the total time that the extraction should take is 27 seconds, producing a consistent cup each time. If the time is out then the only variable left to alter is the grind—more coarse or more fine—accordingly as the dose remains the same.
Hario Scales, like the ones we use
The above recipe of 23.5 grams in with 43-45 grams yield over 27 seconds is subject to change due to temperature, humidity, age of the roast and a myriad of other factors. It’s simply a guide and a set of variables that work for us, time after time. By coupling a pair of scales right next to the grinder and consistently dosing the same amount, I’m confident that each shot should taste the same provided the grind is calibrated correctly.
Essentially what you taste should be the same coffee every time, and it’s because of our practice that I’m so confident in our consistency, in our ongoing effort to turn this dark art of coffee making into a science.