Is blooming necessary for pour-over coffee? What is the purpose of blooming in drip coffee? What is the goal of blooming pour-over coffee? Can pour-over coffee be made without blooming?

After FrontStreet Coffee published yesterday's post on "How to Achieve Perfect Blooming," some friends became curious about one question: "Can pour-over coffee be made without blooming?"

Undoubtedly, this is certainly possible! However, this "possibility" comes with certain conditions. First, we need to clarify one point: the purpose of blooming.

In previous articles, FrontStreet Coffee has always mentioned: the purpose of blooming is to degas coffee for better extraction. This is because coffee grounds often contain rich carbon dioxide. When this carbon dioxide is present, hot water finds it difficult to dissolve the flavor compounds from the coffee, and the brewed coffee is very likely to turn out thin and tasteless. Let's take a look at the brewing comparison that FrontStreet Coffee conducted below!

The Blooming Comparison Experiment

What FrontStreet Coffee aims to compare here is "the difference between brewing pour-over coffee with and without blooming." For this purpose, we need to brew two pots of coffee using the same beans and the same parameters, with the only difference being that one pot will include blooming while the other will not. Finally, we'll compare their differences through tasting and concentration measurements.

Experimental Setup

For this brewing experiment, FrontStreet Coffee will use two relatively fresh beans to brew two sets of coffee! One is a light roast coffee bean from FrontStreet Coffee's selection—FrontStreet Coffee Ethiopia·Guji, while the other is a dark roast coffee bean from FrontStreet Coffee's selection—FrontStreet Coffee Sumatra·Golden Mandheling. The extraction parameters are as follows:

Coffee amount: 15g
Coffee-to-water ratio: 1:15
Grind size: 85% pass-through rate with a #20 sieve
Brewing time: 1 minute 50 seconds
Water temperature: 94°C for light roast Guji / 90°C for dark roast Golden Mandheling
Brewing method: Single-pour technique

Brewing process: Let's skip directly to the results!

Results and Analysis

Guji without blooming: The extraction rate was 17.86%, tasting quite fresh with light fruit acidity, subtle tea aroma, but the flavors weren't prominent, and the overall taste was rather acidic.

Guji with blooming: The extraction rate reached 19.25%, with significantly fuller taste and more prominent flavors. One could clearly taste citrus, berries, white floral notes, as well as oolong tea flavors. The overall mouthfeel was smooth, with balanced flavors—quite excellent!

Golden Mandheling without blooming: The extraction rate was quite low at 16.19%. The mouthfeel was thin, with only a layer of nutty flavor.

Golden Mandheling with blooming: The extraction rate reached 18.27%, with a much richer mouthfeel and more prominent flavors. The sweetness of caramel, aroma of chocolate, as well as spiced and pine notes in the aftertaste could all be clearly captured. However, due to using the single-pour technique, the mouthfeel wasn't as rich as what the three-stage pouring method would produce.

As we can see, whether for dark or light roast coffee, even when parameters such as beans, time, grind, and water temperature are identical, the version brewed without blooming produces flavors that are far inferior to the one with blooming. We can also clearly observe the differences in extraction rates between the two, especially for the dark roast group with sufficient carbon dioxide content, where the difference is even more significant. This sufficiently demonstrates the importance of blooming for pour-over coffee in conventional brewing.

However, this doesn't mean that pour-over coffee necessarily requires blooming. Under certain conditions, the blooming step can indeed be omitted! But these conditions are quite demanding, referring to both the beans and the parameters.

When Can Pour-overs Skip Blooming?

As mentioned earlier, the purpose of blooming is to release carbon dioxide that hinders extraction. Therefore, when the coffee beans no longer contain carbon dioxide that impedes extraction, the blooming step naturally becomes unnecessary.

But generally, we wouldn't wait until this point to start brewing! As we all know, the presence of carbon dioxide isn't entirely negative. Besides its effect of hindering extraction, its presence brings many positive benefits. For example, it allows flavor compounds to remain in the coffee beans for longer, or it slows down water penetration speed, extending extraction time and increasing extraction efficiency...

Besides brewing coffee beans without carbon dioxide, there's another scenario where coffee can be brewed without blooming—that is, using brewing methods that don't include blooming.

As we all know, there are numerous pour-over coffee brewing methods, many of which don't include blooming. For example, the drip method, single-pour method, stirring method, and so on. The reason these brewing methods don't require blooming is that they release or overlook the effects of carbon dioxide through some extreme methods or parameters.

For example, in the drip method, the first half involves drip-style water pouring, which then seamlessly transitions to normal water pouring without the blooming action. In reality, during the drip-style water pouring, the carbon dioxide in the coffee grounds is already completely released. Because drip-style moistening of the coffee grounds takes a relatively long time, many coffee grounds that have already been moistened by water will complete carbon dioxide release during this period.

Then there are the stirring method and single-pour method! The stirring method uses vigorous manual stirring to quickly extract flavor compounds and carbon dioxide from the coffee grounds, naturally eliminating the need for long blooming to remove carbon dioxide. Meanwhile, the single-pour method uses high water temperature and fine grinding to increase extraction efficiency, accelerate carbon dioxide release, thus making the dedicated blooming step unnecessary.

Besides these, there are many similar methods that FrontStreet Coffee won't list one by one. But we need to understand that these brewing methods all tend to test the barista's understanding of brewing, whether in parameter usage or water control proficiency. They're also more troublesome to execute, so few people typically use them.

In conclusion, pour-over coffee brewing can indeed be done without blooming, but the conditions are relatively demanding. Meanwhile, brewing methods that include blooming help us simply and stably brew a delicious pot of coffee, which is why most current mainstream brewing methods include the blooming step~

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