How does extraction time change espresso from coffee machines?

Espresso extraction is unusually sensitive to time because coffee machines push water at high temperature and around 9 bar of pressure, so even a 3-second difference changes the flavor in the cup. Traditional guidance held extraction to 20-30 seconds, while current recommendations lean toward 25-30 seconds, using a double basket, weighing the liquid instead of measuring volume, and aiming near a 1:2 ratio of grounds to liquid.

Time works as a practical tool rather than a fixed rule. It helps with grind adjustment, points to the flavor direction in the cup, and verifies whether extraction is stable. Medium-light roasts and large dose scenarios generally call for a slightly longer extraction time to reach a suitable result. As bean quality, roast levels, and coffee machines have evolved, older ounce-based formulas no longer apply cleanly.

In the world of coffee extraction, time is a seemingly simple yet extremely critical variable. Different brewing methods have different time requirements, and espresso, due to its extremely high extraction efficiency, is far more sensitive to time than other methods—even a mere 3-second difference can make the flavor in the cup completely different. This article will discuss espresso extraction time, tracing the evolution from the traditional 20–30 second approach to the modern recommended 25–30 second approach, analyzing how time aids grind adjustment, indicates flavor direction, verifies extraction stability, and explaining why medium-light roasts or large dose scenarios require appropriately extended extraction time.

Different coffee preparation methods and extraction recipes have different time requirements. When we control the extraction time within the required range, there is a higher probability of producing a cup of coffee with suitable flavor. Compared to other extraction methods, espresso is even more demanding when it comes to controlling time.

With the support of fairly high water temperature and 9 bar of high pressure, the extraction efficiency of an espresso machine is very, very high, which makes extraction extremely sensitive. Even if the espresso extraction time differs by only 3 seconds, the taste when drinking it will be very different. So, time is very important for espresso extraction! In the era when espresso extraction was still measured in ounces, whether the coffee extracted was one ounce or two ounces, single or double, made with 9g of grounds or 18g of grounds, people would control the extraction time within the range of 20–30s.

But times have changed. The quality of coffee beans, the degree of roasting, and the functions of coffee machines have all undergone tremendous changes, and it is difficult for us to still apply the old formulas to extract espresso. So what have the key points of espresso extraction become now? Actually, Front Street Coffee believes everyone already understands them very well:

① Use a double basket as the extraction unit for espresso;

② Espresso liquid is calculated by weight instead of volume;

③ The extraction ratio of coffee grounds to coffee liquid tends toward 1:2;

④ The extraction time is more within the range of 25–30 seconds.

This is currently a relatively commonly used and recommended espresso extraction recipe for major coffee shops (for dark-roasted beans): use a double basket for extraction, then keep the grounds-to-liquid ratio at 1:2 and the extraction time within the range of 25–30 seconds. Through this recipe, we can quickly find the appropriate grind size and produce an espresso with a relatively suitable extraction yield and flavor. Of course, for espresso, time is not just an “auxiliary” parameter for quickly adjusting the grind. Time can also be a reference basis for flavor. Through it, we can roughly judge the flavor direction of a cup of coffee: for example, we use 20g of dark-roasted coffee grounds and extract at a grounds-to-liquid ratio of 1:2. If the extraction time is less than 25 seconds, then this espresso is very likely to be under-extracted, with a thin body and a sour taste and other negative conditions; if it exceeds this time, then the espresso is likely to be over-extracted, with burnt bitterness and harsh flavors (limited to the current extraction recipe, 20g grounds, dark-roasted beans) .

At the same time, time is also an indicator that can determine whether extraction is stable. For example, after we have adjusted to a cup of espresso with suitable flavor, in the next 2–3 espresso extractions, we can observe whether there is a relatively large time deviation. If the deviations are all within one second, then this extraction parameter is relatively stable, because during adjustment it was not affected by too many other factors (such as insufficient pressure in the bean hopper, residual grounds in the hopper, and other conditions that affect extraction) ; but if the deviation is relatively large, exceeding 2 seconds or more, then it indicates that the cup of espresso with suitable flavor had influencing factors appear during the extraction process, and we need to re-establish the espresso recipe. So, everyone can see how important time is for espresso extraction~

But!! What we need to know is that the 25–30 second extraction time range is not absolute. This time range is more aimed at dark and medium-dark roasted coffee beans. Because this type of coffee is not very “resistant to extraction,” the extraction time does not need to be too long, and the dose is limited to within 20g. For some medium-light roasted coffees that are relatively “resistant to extraction” (difficult to extract), or for extractions with a larger dose, the extraction time needs to be extended accordingly, so that the substances in the coffee can be appropriately extracted. Not to mention espresso extraction with pre-infusion or a secondary dispersion screen added, which requires even longer time~

Front Street Coffee (FrontStreet Coffee)

No. 10, Baoqian Street, Yandun Road, Dongshankou, Yuexiu District, Guangzhou City, Guangdong Province

The above content is compiled by CoffeeHunters, a coffee news website.