How Much Coffee Should You Use for Espresso? Can You Taste the Difference Between 0.5g Variations?

"Dosing" is an auxiliary function featured on most commercial espresso grinders. The dosing function of a grinder allows you to set the amount of coffee grounds produced, for example, if you set the weight to 20g, the grinder will produce 20g of coffee grounds. This sounds like a very convenient feature because it can save us the step and time of weighing the coffee grounds.

However, many coffee shops, including FrontStreet Coffee, don't rely solely on the grinder's dosing function for their production. Instead, they use an electronic scale to measure the coffee grounds.

The reason is simple: most grinder dosing functions aren't very accurate. Due to channeling, static electricity, and many other factors, the final amount of coffee grounds will have some deviation from the actual setting. This value will fluctuate depending on the grinder's quality and usage time. For example, FrontStreet Coffee's espresso grinder, after many years of use, has a fluctuation of about 0.3g to 0.5g. "Just a few tenths of a gram? Isn't that negligible?" Many friends immediately raised this question after hearing FrontStreet Coffee's explanation. It's understandable, after all, for other coffee brewing methods like pour-over or siphon, such a small difference indeed won't have a significant impact.

However, for espresso coffee, this difference of just a few tenths of a gram of coffee grounds is already significant! Even if the difference in coffee grounds is only 0.2g, the extracted coffee will have noticeable differences. Why? Because espresso machines use pressure-assisted extraction. Typically, espresso machines use about 9 bar of pressure to extract espresso, and for a 58mm diameter coffee puck, this means it must withstand nearly 240 kilograms of force (about the weight of three adults) during extraction. Such high pressure allows coffee substances to be quickly dissolved with very little water in a short time, which is why espresso machines can produce highly concentrated Espresso.

However, this also makes espresso extraction relatively more sensitive. Even slight changes in the amount of coffee grounds or grind size can cause significant differences in coffee extraction and flavor. This might not be very obvious just from description, so you can look at a comparison conducted by FrontStreet Coffee below. With this comparative data, I believe you can more intuitively feel the differences caused by changes in the amount of coffee grounds.

FrontStreet Coffee used 19.5g, 20g, and 20.5g of coffee grounds to extract two espressos each, with each espresso having the same liquid weight of 38ml. Then they measured the average time and extraction rate for each group of espressos, finally obtaining the following results:

Using coffee grounds amount | Extraction time | Extraction rate
19.5g | 27s | 22.37%
20.0g | 29s | 21.70%
20.5g | 33s | 21.42%

As you can see, the extraction time gradually increases as the amount of coffee grounds increases. This is because the amount of coffee grounds determines the thickness of the puck. When there are more coffee grounds, hot water needs more time to pass through the puck, and vice versa. The extraction rate, however, gradually decreases as the amount of coffee grounds increases. This is because the change in coffee grounds with a fixed liquid amount causes a change in ratio, which is why the coffee's extraction rate changes accordingly.

Through tasting, we can clearly distinguish the differences between the three. In terms of flavor, there weren't many changes because the Warm Sun Blend was used, so the flavors were all whiskey aroma, butter cookies, with some berry notes. The most obvious changes came from the texture and taste. The first espresso (extracted with 19.5g grounds) had a relatively thin texture but a noticeable bitter aftertaste; the second espresso (extracted with 20g grounds) had a moderate texture, balanced taste, and higher sweetness; while the third espresso (extracted with 20.5g grounds) had the thickest texture among the three, but its flavor performance was lacking with not much aftertaste.

The reason for the differences in texture and taste is that the different amounts of coffee grounds caused changes in concentration and extraction rate. The reason the middle one tasted best is because it was the optimal parameter that FrontStreet Coffee tuned earlier today! So now you know that even just a few tenths of a gram of coffee grounds can have a very obvious impact on espresso extraction. The greater the difference in the amount of coffee grounds, the greater the impact. If you're making coffee at home for your own satisfaction, then of course, you can do whatever makes you happy without being too "nitpicky" - after all, it's for you to drink. But if you're serving customers in a coffee shop, it's better to pay a little more attention to details and be more rigorous. Although customers don't know whether your parameters are correct, they can still judge whether it tastes good or not~

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473