Should You Wait for Water to Finish Flowing Before Adding More in Pour-Over Coffee Brewing? Correct Pour-Over Coffee Brewing Techniques!

Understanding Multi-Pour Water Injection Timing in Pour-Over Coffee

Many beginner coffee enthusiasts often face a question when using multi-pour water injection for brewing coffee: "When should the hot water be injected?"

Multi-pour water injection refers to the method of dividing the hot water used during the coffee brewing process into multiple injections. For example, the three-pour method frequently used by FrontStreet Coffee is a typical multi-pour water injection technique. When using multi-pour brewing, the question lies in the timing of the third and subsequent pours: should the next injection be made before the previous pour has completely drained, or should it wait until the previous pour has fully finished?

Different coffee bloggers share varying timing for water injection, and even FrontStreet Coffee's content alternates between different approaches. This has left many friends confused about when to begin injecting the next pour of hot water. However, the matter isn't as complex as everyone imagines. If the number of pours isn't excessive, the impact won't be significant. To determine when hot water should be injected, we simply need to understand how different injection timings affect extraction. This time, FrontStreet Coffee will share practical insights on how different injection timings affect coffee and how to choose the right moment for hot water injection.

Brewing Experiment

For this experiment, FrontStreet Coffee will brew two groups of coffee using the three-pour method, with two pots per group. The grind size, water temperature, coffee-to-water ratio, and pouring method will be identical for each pot. The only difference will be the timing of the third hot water injection. One group will receive the third pour when the previous pour is nearly drained, while the other group will wait until the previous pour has completely finished. Let's see how these different injection timings affect the coffee.

To minimize the impact of human brewing variables, FrontStreet Coffee will use a pour-over coffee accessory—the shower dripper—in this experiment. This device helps distribute the injected hot water, preventing significant extraction differences caused by variations in flow rate or agitation (though some differences will still occur, they'll be comparatively smaller).

Experiment Parameters

Since this experiment doesn't evaluate coffee flavor, FrontStreet Coffee randomly selected a bean for testing. The extraction parameters are as follows:

• Coffee amount: 15g
• Grind setting: Ek43 setting 10
• Coffee-to-water ratio: 1:15
• Brewing water temperature: 92°C
• Dripper used: V60
• Pouring method: Three-pour technique

The brewing process for all four pots was similar: first, 30ml of hot water was used for a 30-second bloom. After the bloom ended, 120ml of hot water was poured over 20 seconds, bringing the total time to 50 seconds. Then, depending on the specific objective, the third pour of 75ml was injected at different nodes, with the third pour completed within 15 seconds.

Experiment Results

With proper control of pouring rate, the flow rate of all four coffee pots was nearly identical. The second pour of hot water in all four pots was almost completely drained at around 1 minute and 10 seconds, at which point FrontStreet Coffee selected two pots to receive the third pour of hot water. The other two pots received the third pour after the hot water in the filter had completely drained (at around 1 minute and 20 seconds). After waiting for the coffee to finish dripping, we could proceed to measure the extraction rate.

The two pots with earlier third pour injection had a total extraction time of 1 minute and 50 seconds. Through measurement and calculation, their extraction rates at 33°C were 16.33% and 16.88% respectively. The two pots that received the third pour after the second pour had completely drained had a total extraction time of exactly 2 minutes, with extraction rates at 33°C of 17.30% and 17.58% respectively. This shows that even with similar extraction parameters and pouring methods, extraction rates still varied due to different injection timings. There are two reasons for this difference: time and liquid concentration.

Understanding the Impact

In the article "Why Multi-Pour is Recommended for Pour-Over Coffee," FrontStreet Coffee shared that multi-pour brewing can effectively increase extraction rates for similar reasons: it provides more contact time between water and coffee grounds, while the concentration of the extracted coffee liquid remains relatively lower. Therefore, you should now understand how to determine injection timing! When you want to achieve higher extraction rates, you can choose to inject the next pour after the previous pour has completely drained. For example, when overly coarse grinding or low water temperature causes the previous pour to flow too quickly and lead to under-extraction, we can wait for the water to completely drain before injecting the next pour. Alternatively, you can divide the pouring into more segments to further increase the coffee's extraction rate.

On the other hand, if you want to appropriately suppress the increase in extraction rate—such as when water temperature is too high or grinding is too fine, causing the previous pour to flow slowly due to clogging and leading to over-extraction—you can advance the injection timing. When the previous pour has about one-third remaining (or is nearly drained), you can inject the next pour of hot water. It's worth noting that many friends think that extended waiting time will cause the temperature of the hot water and coffee bed to decrease, which in turn would lower the extraction rate. However, the impact of temperature is not as significant as that of time and concentration, so we don't need to worry about the effects of temperature reduction due to extended time~

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