You may have heard this statement a long time ago, but I don't know why, but I want to make it completely clear today. Put down your 30ml measuring cup and bullet cup. It's time for the weight to come out. Go weigh your espresso!
There are many problems in measuring concentration and extraction by volume, but it is a little unstable. Volumes should be avoided for the following reasons.
The bullet cup is too small.
The cup is too small, so there is no room for fault tolerance when reading the scale. Even a lost deviation will be greatly amplified. In other words, the reading of the bullet cup is wrong by one millimeter, which will lead to a maximum difference of 5% in the total amount of milliliters.
We usually observe the liquid meniscus with naked eyes to determine the specific scale.
With the naked eye, you can't see how deep the water is (refraction of light), let alone the opaque concentrated solution. You can't see the meniscus, which is another uncertain factor.
Grease foam changes every day.
This is perhaps the most urgent reason for not using bullet cups. The fresher the coffee, the richer (thicker) the oil foam comes out. This is because there is still a lot of carbon dioxide in fresh coffee beans that cannot escape. The longer the time, the more carbon dioxide escapes and the less oil foam.
Almost all oil bubbles are bubbles, and the density is much lower than that of concentrated solution, so it is meaningless to measure them in milliliters.
When beans were tested on the 3rd day and14th day, the oil bubbles were obviously different. Using a bullet cup to measure these two cups of concentrated solution will get completely different results.
Go and get a decent scale
Most cafes use cheap names from Yi Bei. It was ok at first, but it washed white as soon as it entered the water. It looks cheap and saves money. If you change it frequently, it will be more annoying.
Acaia's waterproof scale Lunar just came into our sight. I highly recommend this one, it is the best. Don't think about it during the exam, just take the exam.
How to weigh concentrated solution
If you haven't used a scale before, here is a quick guide.
Grinding, weighing, powder distribution and pressure filling.
clear
Extract, lineage
Lift the cup and shake the balance back and forth.
I guess it should be shaking the balance back and forth, in order to make the bubbles disperse as much as possible and get more accurate results.
Make sure the scale is level.
Stop the extraction before reaching the target gram (about 2-8g), which depends on the water outlet capacity of the powder bowl and the weighing delay.
Multiplying a single copy by 2 is very inaccurate. If shunting is necessary, please use two cups and two scales.
Trade-offs are the best solution.
Chefs, bakers, chemists and jewelers all weigh their treasures with scales, because what they need is accuracy and precision.
Why don't we pursue coffee? !