The first time I saw someone placing a glass carafe over a scale for brewing coffee, I grinned. I joked about it and made some silly comments about it. But it’s vital and makes quite a difference when it comes to obtaining repeatable brewing results.
When calculating a brewing ratio, we know how much coffee we need to serve a specific amount of coffee, with a target strength. In each case, we can brew a more robust or lighter cup of coffee, depending on many factors. We might want a café au lait, so we brew using a 12:1 ratio. In contrast, if we’re drinking a fine Gesha, it’s more likely that we drink it black to appreciate all of its attributes. In these cases, it’s more common to use brewing ratios around 16:1 and 18:1.
But to know the measures isn’t accurate by sight. A scoop can hold different weights each time. As a result, coffee can be stronger or weaker than expected.
Baristas weren’t the first to use scales to determine the proportions of their ingredients accurately. It’s more common in cooking, and many food companies use commercial-grade scales for mass production. If we use scales, it’s easier to calculate recipes appropriately. We might think, at first, that using scoops is precise enough, but organic ingredients like coffee can weigh differently even with the same volume.
Grinding on demand is the best way to get delicious coffee, and at the same time, makes it more challenging to brew repeatable recipes without a scale. Coffee beans shape can be deceiving, and a scoop can contain a very different weight each time we measure.
For coffee grounds, it’s slightly less complicated, but it can still be very different to measure two full scoops compared to two almost full scoops. The differences in weight between similar volumes depend on green coffee density, the type of roasting, and the grind size.
So, a scale is handy to reduce variability or to adjust our brewing technique more appropriately. Without a scale, we can only guess if our cup of coffee will be stronger than the last one or if we need to grind finer. It’s genuinely essential for calibrating the grinding size, and it’s impossible to repeat a brewing recipe without controlling the weight of coffee we are adding.
For this reason, calculating brew ratios is more straightforward when using a scale. Water is a very convenient ingredient. When measuring water weight and volume is very easy to convert the amounts. It’s among the very few substances that weigh 1 gram per milliliter, making it very easy to work with for coffee brewing.