This is a quick post about the “Bloom” of the coffee.
When brewing coffee we typically allow the coffee to “bloom1” for anywhere between 30 seconds and 4 minutes, during this time the coffee is releasing gasses and causes ground coffee to form a large crust on top of the water. We then break the crust and, either continue our brew, or finish it.
It seems to me that we are all missing something. This crust that forms can be as mush as 2 inches thick and the grounds can be completely suspended above the water, which is supposed to be extracting said grounds. There is a separation of our soluble and our solute, which in turn leads to a uneven extraction.
I did a small experiment and brewed 3 french presses, all with the same amount of coffee, water, steep time, etc.
1. The first press I let sit with a “bloom” for 1 min, after that, I broke the crust and continued my brew for another 2 min and then Pressed. (My standard way of brewing coffee.)
2. The next press I constantly stirred2 and never let a crust form, then pressed at 3 min.
3. The final press I let sit with a “bloom” for 2:55 before breaking the crust and pressing at 3 min.
I then tasted them side by side and the differences were very noticeable. (I don’t have TDS meter so I can not be sure of the extraction %, some help here would be appreciated) I would suspect that the TDS % would be the lowest in 3, highest in 2 and, fall somewhere in between with 1. In the cup it was obvious the 3rd was the least developed and least complex, leading me to believe that the bloom separates the coffee from the water and leads to an under-extracted brew.
So why do we let coffee bloom?
This experiment lead me to rethink my brewing techniques and led to a new technique emerging.
Andrew Lopez had a clever idea of letting the coffee “bloom” underwater in the press. Here is his post on the subject.
Here is an outline of the method:
1. Start with your normal parameters of weight, time, temp, etc.
2. Grind your coffee and fill your press with water, preferably on a scale, until you reach your TOTAL amount of water needed for your brew.
3. Immediately put the press filter in and plunge half way down (you might feel some resistance as the coffee is still trying to expand, but get it half way down), submerging the crust and coffee mass under the water. (Bloom Underwater)
4. After about half of your brew time you can pull the press filter up and continue your brew.
5. Press your coffee and enjoy a FULL extraction.
Taste it side by side by side with your normal press technique and adjust your other parameters if needed.
Comments are very welcome.