Most high-end coffee grinders are used for espresso doses over time, although all official SCA standards are limited by weight. So, what’s the difference? Why do we keep using timed grinders? How do we ensure we are dosing accurately?
To answer these questions, I spoke with Lauro Fioretti, product manager of the espresso machine and grinder manufacturer. The Simonelli GroupIncludes brands like New Simonelli And Victoria Arduino.
Here’s what I found.
Read this article in Spanish Standard Espresso: Molino Con Temporizador Vs. Gravimetric
Lauro Fioretti (back) and 2017 World Barista Champion Dale Harris (front). debt: Victoria Arduino
What are Timed & Gravimetric Grinders?
Let’s take an espresso recipe. This starting point for the recipe is usually the ratio of dry, ground coffee that goes into the portafilter to the beverage that comes out of the espresso machine.
OK, but how to define these amounts? Weight, volume or some other bulk?
Lauro tells me, „In the coffee skills program from SCA, if you go to the barista intermediate or professional level, everything is measured by weight … the brew rate, the recipe, everything happens by weight, not by weight.”
Still on the market, we find both time and gravimetric grinders.
A A timely grind One that grinds coffee for a specific time, set by the barista. Suppose a recipe calls for 18 grams of coffee. After testing, the barista found that it takes 5.8 seconds to grind 18 grams of coffee. So, this is where the grinder is set up.
A Gravimetric GrinderOn the other hand, the weight of the coffee is measured as it lands in the portafilter. It switches off the motor when a pre-programmed weight (set by the barista) is reached.
You may also like: How to improve consistency when making espresso-based drinks
Mythos 2, a gravimetric grinder, is in operation. debt: Victoria Arduino
How accurate are timed grinders?
Grinders always vary in their accuracy. Reliability, quality, maintenance, and degree of accuracy will influence accuracy. (As Lauro says, the Black Eagle Gravimetric Espresso Machine is accurate to 1 gram. Myths 2 (A gravimetric grinder is accurate to 0.1 g.)
With more timed grinders, we need to consider another factor: the relationship between weight and time.
Lauro says, “Every time you change a variable automatically, [even] At the same time, you will have a different size. For example, if you change the grind size, adjust your grinder to coarser or finer, it will make a dramatic difference in the size of the coffee… If you change the type of coffee, again, you will change the size. Coffee delivered.”
Different grinding systems take more or less time to grind. Different coffees have different densities, which affects the volume and grinding time. Baristas have to recalculate the grind time each time they change the coffee and recipe.
Yet this is not the only factor affecting grinding speed. Lauro tells me, „If the bean hopper is full or almost empty… depending on the amount of coffee you have on top of your bean hopper, you can have a different amount of coffee delivered.”
With a full hopper, the weight of that coffee pushes the beans through the burr set, meaning more coffee is ground faster. As more coffees are made and the hopper begins to empty, the pressure slowly drops. With a nearly empty hopper, you can actually see the beans jumping off the blades instead of being ground: a sign of a lack of pressure.
Lauro tells me he put it to the test once. „Grinding size, temperature, all the variables are fixed, we tested the same grinder with a full hopper – a hopper full of beans – and the hopper is almost empty,” he says, „I saw the difference in some grinders. The amount of ground coffee is up to 1.5 grams. It’s Mithos 1’s. Not the case, for example, which is more accurate.”
Many of these complications are eliminated by gravimetric machining; As Lauro says, „It’s a direct measurement…eventually, you’ll gain your weight.”
But what if you could use a time machine?
Ground coffee is weighed on a digital scale. debt: John MarcelOh Stark
How can you ensure consistency?
Ultimately, if you want to be consistent, you need to make sure you use the same amount of coffee each time.
Lauro says, „If you want to be precise [and don’t have a gravimetric grinder], time to go with your grinder and check your electronic scale… check the final product and adjust it manually. Of course, this will take time.”
If you use more than one in the store, it’s worth calibrating your scale periodically. Additionally, you may need to train your employees so that they can use them efficiently and consistently.
Finally, be aware of clumping. Lauro says, „Ground coffee is difficult to measure because ground coffee has static electricity.” As a result, he continues, “there is a tendency to form spikes, so when you grind, because of the friction of the blades, it charges the ground with electricity.
„And because they’re so small — we’re talking about microns — they tend to form clumps, so when they come out of the grinder… at the same time, some clumps can stay in or go out, and some can be made bigger. The difference in total output.”
The Myths 2 There is a „Club-Crasher System”, but without this, even a gravimetric grinder would be somewhat inaccurate due to clumps. So, if your equipment isn’t set up to avoid this, keep that in mind. If a dose has a large number of bunches, weigh it on an electric scale.
Pulling espresso with a bare portafilter. debt: Victoria Arduino
Consistent, accurate espresso shot dosing is critical to both well-extracted espresso and customer retention rates. So, understand your equipment. Know if your grinder is timed or gravimetric. Use a scale if you need to, and be sure to measure it regularly.
Remember: a gram of difference can have a big impact on the consumer experience.
Please note: This article was Sponsored By The Simonelli Group.
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