How Should Coffee Extraction Time Be Calculated? Should Espresso Extraction Timing Start When the Coffee Machine is Activated or When Coffee Begins to Flow?

When to Start Measuring Coffee Extraction Time

Whether for espresso or pour-over, the timing issue often troubles some coffee enthusiasts. For example: when making pour-over coffee, should the timing start before the bloom pour, or after all the water has been poured? Or when extracting espresso, should timing start before pressing the extraction button, or after the coffee begins to flow?

Although there may only be a few seconds' difference between these two approaches, this is a significant variable for coffee extraction, which is why many people feel troubled about it. So, FrontStreet Coffee will share when to start measuring coffee extraction time, and why time is so important!

When Should Extraction Time Measurement Begin?

The measurement of extraction time is actually quite simple to understand. Extraction is the process of using water as a solvent to extract flavor compounds from coffee. Therefore, the moment water contacts the coffee grounds, extraction has already begun! For pour-over coffee's bloom pour and espresso machine's extraction start, you need to press the timer button simultaneously at the beginning.

Otherwise, if you start timing only after completing the bloom pour or when espresso begins to flow, it will create a time error of 7-8 seconds. The appearance of this error will definitely cause significant deviation in your extraction judgment.

Why Is Time So Important?

Because time is also an extraction parameter that can determine extraction efficiency. However, coffee extraction time is not a measurement unit that can be directly controlled! What does this mean? For example: other extraction parameters such as grind size, water temperature, pressure, and water volume can all be actively controlled by ourselves. If you want higher water temperature, you can have higher water temperature; if you want higher extraction pressure, then extraction pressure can be greater, and so on.

But time is different. We cannot directly control it; instead, we need to make adjustments to other parameters to control extraction time. Therefore, when our judgment of time deviates, it will create obstacle after obstacle, whether in coffee extraction adjustments or in communication with other coffee enthusiasts. In other words, when you can accurately control extraction time with minimal variation, it indicates that the other parameters you're using are reasonable and stable.

To put it simply, extraction time is essentially the time it takes for water to pass through the coffee grounds. The higher the resistance of the coffee bed, the more difficult it is for water to pass through. Without external force assistance, water needs more time to completely percolate. During this time, water will continuously extract flavor compounds from the surrounding coffee grounds, meaning that if it stays longer, more substances will be extracted, and vice versa. And for this very reason, time is so important—it's the only parameter that can quickly identify problems when taste issues arise.

Practical Examples

Let's take a pour-over coffee example: if this pour-over coffee tastes somewhat under-extracted, the inevitable cause is insufficient extraction efficiency, which prevents hot water from fully extracting flavor compounds. Many parameters can affect extraction efficiency, making it difficult to determine which parameter is causing the problem. In such situations, we can quickly identify issues by observing the extraction time used.

For example, FrontStreet Coffee sets the pour-over extraction time for 15g of coffee beans at 2 minutes. If this under-extracted coffee's extraction time is less than two minutes, then the problem might be with grind size or pouring technique; if it exceeds two minutes, then it might be caused by insufficient water temperature or inadequate stirring intensity (which can be categorized as technique).

The same principle applies to espresso extraction. With pressure, water temperature, and output volume all fixed, only the amount of coffee grounds and grind fineness can change extraction time. Therefore, when the extracted coffee taste deviates, we will decide whether to adjust the amount of coffee grounds or grind fineness based on the length of extraction time. This is why time is such an important parameter.

Finally, FrontStreet Coffee wants to mention one more point: the reason espresso doesn't immediately flow when extraction starts is because the coffee puck creates extremely high resistance (including carbon dioxide release), and even with pressure assistance, hot water needs a certain amount of time to permeate through. The moment the coffee machine starts extraction, hot water has actually already contacted the coffee puck, whether it's pre-infusion or regular extraction—the same applies to both. This is why espresso extraction timing, like pour-over, should start simultaneously at the beginning.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473