Does Pour Rate Affect the Flavor of Pour-Over Coffee? What Water Flow Rate is Best for Brewing Coffee?

Have you ever struggled with how to pour water when brewing pour-over coffee, or wondered what flow rate to use? One friend asked FrontStreet Coffee, "If only the pouring rate changes while all other parameters remain the same, what changes occur in the coffee's concentration and flavor?"

So this time, following this friend's request, FrontStreet Coffee conducted a comparative experiment. According to the friend's description, "only the second pouring segment changed, with the first method using a flow rate of 3 grams per second, and the second method using 6 grams per second," while FrontStreet Coffee's typical pouring speed is approximately 4-5 grams per second.

Experiment Setup

FrontStreet Coffee typically uses a 3-segment pouring method, so according to the requirements, different flow rates were used for the second segment, while the bloom stage and third segment used FrontStreet Coffee's usual pouring rate.

This experiment will use Ethiopia's Guji coffee beans, with brewing parameters as follows:

Dose: 15g
Grind size: 80% pass-through rate on #20 sieve
Ratio: 1:16
Water temperature: 91°C
Dripper: V60

First Flow Rate Method

First, during the bloom stage, FrontStreet Coffee used a flow rate of 4ml/s to pour 30ml of water, blooming for 30 seconds. The second segment used a rate of 3ml/s to pour 120ml, with pouring completed at 1 minute and 10 seconds; waiting for the water level to drop, the third segment of 90ml began at 1 minute and 30 seconds, with a rate of approximately 4.5ml/s, completing at 1 minute and 50 seconds. The total extraction time until the coffee finished dripping was 2 minutes and 33 seconds.

Second Flow Rate Method

First, during the bloom stage, FrontStreet Coffee used a flow rate of 4ml/s to pour 30ml of water, blooming for 30 seconds. The second segment used a rate of 6ml/s to pour 120ml, with pouring completed at 50 seconds; waiting for the water level to drop, the third segment of 90ml began at 1 minute and 8 seconds, with a rate of approximately 4.5ml/s, completing at 1 minute and 28 seconds. The total extraction time until the coffee finished dripping was 2 minutes and 10 seconds.

Experiment Results

To reduce experimental error, FrontStreet Coffee brewed each method twice. The measured concentrations for the first method with small flow rate were 1.39% and 1.41% respectively. The calculated extraction rates were 20.58% and 20.88%.

The concentrations for the second method with large flow rate were 1.32% and 1.36% respectively. The calculated extraction rates were 19.53% and 20.13%.

Analysis

First, regarding the extraction process, as the friend who raised the question mentioned, changes in pouring rate directly lead to changes in extraction time. When only changing the pouring rate of the second 120ml segment, the difference between 3ml/s and 6ml/s resulted in a total time difference of about 20 seconds.

From the final coffee bed results, both methods had the same coffee bed height, but the first method with small flow rate in the second segment did not raise the height to the final level. Instead, during the last pouring segment, because the flow rate increased compared to before, the coffee bed was raised to the final height seen in the results.

However, the coffee bed heights for the last two pours in the second method were consistent. FrontStreet Coffee cannot prove which method is better or which has defects. Ultimately, it depends on whether the configuration of other parameters is reasonable.

Flavor Comparison

In terms of concentration data, the difference between the two methods is not significant, but the small flow rate indeed extracts more substances, which is actually related to extraction time. If using 3ml/s throughout the entire process, the coffee bed won't rise too high, increasing pouring time while also extending the drainage rate, leading to higher extraction rates. However, it's worth noting that high extraction rates are not necessarily a good thing.

In terms of flavor, both methods exhibit the flavor characteristics of Guji coffee, without any unpleasant negative flavors. The biggest difference between the two lies in sweet and sour sensations. The small flow rate method shows more prominent berry sweetness, while the large flow rate method has more vibrant acidity and richer layering. As for mouthfeel, there wasn't much difference between the two.

Conclusion

Finally, the flow rate certainly affects coffee flavor, as demonstrated in FrontStreet Coffee's experiment - there are differences. However, if the parameter settings are reasonable, coffee brewed with significantly different flow rates can still be within acceptable ranges. Therefore, don't worry too much about how much impact the flow rate parameter can have on brewing. If the coffee doesn't taste good, it might be because your flow rate is incorrect, but more likely, it's because your various parameters are not well coordinated!

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473