"How big is the difference between coffee with a 30-second bloom and a 60-second bloom?" This is a question a friend posed to Front Street Coffee yesterday. You know, this question is actually quite interesting!As everyone knows, blooming is a standard step in pour-over coffee. Specifically, before the official pour, we pre-infuse a small amount of hot water to wet the coffee bed and pause for about 30 seconds. In coffee brewing, this step can greatly improve extraction efficiency and increase the dissolved coffee compounds. Simply put, it makes the brewed coffee taste richer.Front Street Coffee once conducted a test specifically for this. With the same coffee beans and extraction parameters, the extraction yield of coffee with a 30-second bloom was significantly higher than that without blooming, and the difference in taste was enough for a beginner to tell the two apart at first sip. This shows that the impact of blooming on pour-over coffee cannot be underestimated."But if it's as Front Street Coffee says, wouldn't a 60-second bloom be even better than 30 seconds?" This is why the guest friend asked the question at the beginning yesterday.Great! Since a friend has sincerely asked, next Front Street Coffee will do a brewing comparison to share with everyone exactly what kind of difference exists between coffee with a 30-second bloom and a 60-second bloom.
In this brewing session, Front Street Coffee will use three coffees of different freshness for comparison! They are: fresh coffee beans only 3 days after roasting, coffee beans 15 days after roasting at their peak flavor period, and coffee beans 30 days after roasting.Then Front Street Coffee will brew two pots of coffee with each coffee bean, one with a conventional 30-second bloom and the other with 60 seconds, and finally compare the differences by measuring extraction yield and tasting the flavor. Since all three beans are medium-light roast, all parameters except bloom time are identical! As follows:Brewing water temperature: 92°CCoffee-to-water ratio: 1:15Grind setting: Ek43 setting 10, 75% passing a No. 20 sieve, caster sugar grindBrewing method: three-pourAuxiliary equipment: drip shower head(to reduce human influence on brewing)We'll skip the introduction of the brewing process. After Front Street Coffee brewed the coffee, tasting and extraction yield measurement were carried out. The final results are as follows:3-day roast group: 30-second bloom extraction yield 19.95%; 60-second bloom extraction yield 20.33%15-day roast group: 30-second bloom extraction yield 20.21%; 60-second bloom extraction yield 20.49%30-day roast group: 30-second bloom extraction yield 20.37%; 60-second bloom extraction yield 20.58%It can be seen that no matter which group, the extraction yield of the 60-second bloom is indeed a bit higher than that of the 30-second bloom, but the gap between them is smaller than you might imagine—not by much. The difference in taste is the same: the coffee with a 60-second bloom tastes just a tiny bit stronger than the 30-second one, but not much stronger.Although both differ by 30 seconds of bloom time, the experimental results of "0 seconds vs. 30 seconds" and "30 seconds vs. 60 seconds" can be said to be vastly different. The former comparison can be accurately distinguished by a beginner in a blind test, while the latter requires a barista to taste carefully to tell the two apart in a blind test(except for the first group, which is more obvious). The reason is that the effect we need from blooming has already been mostly achieved in the brief 30 seconds.Why does pour-over coffee need blooming?The reason adding blooming can improve coffee extraction yield is mainly that it allows the coffee grounds to expand and release the carbon dioxide accumulated during roasting.Coffee extraction proceeds through concentration gradient differences! When hot water contacts the coffee grounds, the flavor compounds in the coffee grounds transfer into the lower-concentration water due to the concentration difference. In this process, a problem we need to face is that water cannot immediately enter the interior of the coffee grounds to reach the internal flavor compounds.This is because the carbon dioxide inside the coffee grounds is rapidly released upon contact with hot water, which slows the speed at which hot water reaches the interior of the coffee grounds. If a large amount of water is poured to extract before the water has fully wetted the coffee grounds, then much of the hot water will not be able to fully extract the flavor compounds in the coffee.Therefore, we need the action of blooming to complete the release of carbon dioxide.By using a small amount of hot water to pre-wet the coffee grounds, allowing carbon dioxide to escape and hot water to penetrate inside, the subsequent hot water can better dissolve the flavor compounds in the coffee grounds, making extraction more uniform and more efficient.But the time required for hot water to complete this job will vary depending on the state of the coffee beans and the parameters used. I believe some friends have already noticed from the experiment shared by Front Street Coffee above that the first group's two pots of coffee had the largest difference in extraction yield, and the further along, the smaller the difference between the coffees.This is because the coffee beans used in the first group were the freshest, with the highest carbon dioxide content, and needed a longer bloom to release the carbon dioxide from the coffee grounds, so the difference between the two pots in the first group was relatively large. In addition, factors like roast level, density, and extraction parameters will all affect the required bloom time.But if you have to compare them one by one to find the appropriate bloom time, the difficulty for beginners is somewhat too high. So generally Front Street Coffee recommends beginners first use"30 seconds" for blooming, which is a relatively safe blooming plan. It won't be too short to allow insufficient degassing, nor too long to waste time. As long as the right parameters are used, this time can still allow the coffee to be fully extracted.And once we can steadily brew a delicious cup of coffee, it won't be too late to start learning advanced knowledge then. Of course, if you have a need right now, you can directly click《Portal》to jump over and learn more~ The above content is compiled by CoffeeHunters, a coffee news website.
