V60 Filter Blooming

To bloom, or not to bloom?

To bloom, or not to bloom? At least for us coffee nerds, that's the question of questions.

Blooming is one of the wisdoms we all know - like rinsing out paper filters or pressing tampers selectively. But we never really think about it. We bring light into the darkness and clarify all questions: What is actually to be achieved with this? Is there an even better solution? Will the coffee gods hate me if I don't do it?

Blooming is the very first part of a pour-over. It involves adding a small amount of water to the dry coffee grounds and letting it swell for about 30 seconds. Some people like to stir it, others swirl it around, and still others just let it sit through at its leisure.

Blooming has two goals. One is to moisten all of the coffee as quickly as possible to ensure that there are no dry clumps. These could lead to an uneven extraction that does not include part of the coffee. Secondly, CO2 is released from the coffee. Roasting coffee produces CO2 that is trapped in the beans and must be released in order to brew the coffee properly. This release is the cause of the bubbles that appear when you infuse the coffee with water. In English, this is why we speak of "blooming": the coffee grounds blossom and unfold.

But is this process really necessary? Some coffee brewers, especially those who make a pour-over in cafés, are rather frustrated by the blooming: 30 seconds is a long time for coffee! This has led some to experiment with so-called "no-bloom" methods. Most methods (like this one) involve drilling a small depression into the dry coffee bed, allowing the grounds to fill up more quickly as you pour the water in from the center. This procedure is necessary in place of the swirling or stirring normally used in brewing. The process can then simply continue until all the water has been added.

Not only does this procedure make the whole thing faster, it also makes it easier: one infusion, done in less than two minutes. But there are a few challenges, too. First, no-bloom takes a little longer to saturate all of the coffee, which can lead to uneven extraction and a less balanced cup.

Further, most no-bloom brewers use a lower brewing temperature to reduce CO2 release. Hotter water releases CO2 more quickly, which can over-stir the coffee in a no-bloom brewing process and lead to excessive extraction and bitterness. This can be a particular problem with lighter-roasted, hard-to-extract coffees, which can become under-extracted and sour at lower temperatures.

Even though the no-bloom method makes for a faster and easier recipe, it brings new challenges that you need to be aware of. It is not a miracle cure that solves all problems, just a different approach. Depending on your priorities, you can make better use of the strengths and weaknesses of each method. Try it out for yourself!

Still have questions? Learn more about blooming, and anything else you want to know about filter coffee, in a filter class with our trainer, Joel.