We use the term “metal” here to denote something real. A “myth,” on the other hand, not real. The question we’re asking is whether or not the “bloom” phase in the pour over process actually adds flavor.
Most coffee experts instruct when you first pour hot water into your pour over receptable, to dispense 50-60g (though Stone Creek Coffee advocates for 30g) hot water and wait 30-40 seconds. (It’s called a “bloom” because as hot water soaks in to the ground coffee and the steam rises, the grounds rise and appear to “bloom.”) These experts say this bloom period expels the full foray of flavor from the bean.
However, if the entire pour over process should last approximately three minutes, whether allowing for a bloom period or not, does the “bloom” really make a difference in chemistry and flavor? Or, is this “bloom” advocation more of an aesthetic one?
I did some research, and you can do some of your own. According to Intelligentsia Coffee in Chicago, the bloom “allows CO2, which is trapped in the coffee, to escape.” Interesting. While I find this scientific explanation intriguing, I’m not entirely sold. CO2 seems to be able to escape during the entirety of the pour over process. I mean, we’re not putting a lid over the top.
Verdict: We still go for the bloom.
For pour over methodology in video format: How to Brew a Pour Over (by Intelligentsia Coffee)