How Important is Coffee Extraction Time? What's the Connection Between Espresso Grinding and Time?

Understanding Coffee Extraction

What we commonly refer to as coffee extraction is the process of using water as a medium to dissolve flavor compounds from coffee grounds. It's important to understand that this extraction process requires time—the longer the extraction time, the more substances will be dissolved. However, not all compounds in coffee should be extracted. Therefore, we need an appropriate time to extract them in suitable amounts.

Different coffee brewing methods and extraction protocols have different time requirements. When we control the extraction time within these required ranges, there's a higher probability of brewing a coffee with balanced flavor. Compared to other extraction methods, espresso extraction demands much stricter time control.

The Critical Role of Time in Espresso Extraction

With the support of high water temperature and 9 bar pressure, espresso machines achieve extremely high extraction efficiency, making the process particularly sensitive. Even a mere 3-second difference in espresso extraction time can result in significantly different flavors. Therefore, time is absolutely crucial for espresso extraction!

Back when espresso was measured in ounces, whether extracting one or two ounces, single or double shot, using 9g or 18g of coffee grounds, people would control the extraction time within the 20-30 second range.

Modern Espresso Extraction Guidelines

However, times have changed. Coffee bean quality, roast levels, and espresso machine capabilities have evolved dramatically, making it difficult to apply old formulas to modern espresso extraction. So what are the key points for espresso extraction today? In fact, FrontStreet Coffee believes everyone is already quite familiar with these:

• ① Using double baskets as the standard unit for espresso extraction
• ② Measuring espresso liquid by weight instead of volume
• ③ Coffee grounds to espresso liquid ratio trending toward 1:2
• ④ Extraction time primarily within the 25-30 second range

This is currently a commonly used and recommended espresso extraction protocol in many coffee shops (for dark roasted beans): using double baskets for extraction, with a grounds-to-liquid ratio of 1:2, and extraction time between 25-30 seconds. With this approach, we can quickly find the appropriate grind size to produce espresso with both suitable extraction yield and balanced flavor.

Of course, for espresso coffee, time is not just an "auxiliary" parameter for quick grind adjustments. Time can also serve as a reference for flavor profiles—we can use it to roughly determine the flavor direction of a coffee. For example, if we use 20g of dark roasted coffee grounds with a 1:2 brew ratio:

If the extraction time is below 25 seconds, this espresso will likely show under-extraction characteristics, with thin body and overly sour flavors. If it exceeds this time range, the espresso will tend toward over-extraction, exhibiting burnt, bitter, and harsh flavors (limited to the current extraction protocol: 20g grounds, dark roasted beans).

Time as an Indicator of Extraction Stability

Additionally, time is also an indicator that can determine whether extraction is stable. For example, after adjusting to produce an espresso with balanced flavor, we can observe whether the next 2-3 espresso extractions show significant time variations. If the variance is within one second, then this extraction parameter is relatively stable, as it wasn't affected by too many other factors during adjustment (such as insufficient bean hopper pressure, residual grounds in the hopper, etc., which can affect extraction).

However, if the variance is larger, exceeding 2 seconds, this indicates that affecting factors were present during the extraction of that well-balanced espresso, and we need to reformulate our espresso protocol. So now you understand how important time is for espresso extraction!

Flexibility in Extraction Time

However!! We must understand that the 25-30 second extraction time range is not absolute. This time range primarily targets dark and medium-dark roasted coffee beans. Because these types of coffee are less "extraction-resistant," they don't require long extraction times, and the amount of grounds is limited to under 20g.

For some medium-light roasted coffees that are more "extraction-resistant" (harder to extract), or extractions with larger amounts of grounds, the extraction time needs to be extended accordingly to properly extract the compounds from the coffee. Not to mention extractions that incorporate pre-infusion or double shower screens—they require even longer times!

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FrontStreet Coffee (FrontStreet Coffee)
No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

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