In this follow-up post I will go over the recipe and complete brewing technique I used for both cups tasted for comparison in the last blog entry. Note: If you haven’t already, go read that first!
The recipe for both Chemex and Hario V60:
Dose: 18.0 grams of ground coffee
Grind: 4.25(V60) and 4.5(Chemex) on our EK-43
Total Water: 336 grams(mL)
Bloom: 45 grams water and quickly stir*, then wait 30 seconds
The rest: 3 more slow pulses of about 100g water, reheating to boil between each pulse and pouring the last drop of the 336g at the 1 minute 35 second mark.
*I omitted the stirring step for the Chemex
I’m a proponent of stirring right after the bloom(very first pour of water). This ensures that all the coffee grounds start brewing at the same time and for the same amount of time throughout the brew as opposed to waiting for the slow drip of the water to make its way through the coffee bed, losing temperature and extracting energy.
Something can happen though when you stir the bloom: The smallest dusty bits of the ground coffee or “fines” can migrate down to the bottom of the brew bed. In the case of the Chemex the brew bed is a cone made of a super thick piece of paper which is also folded to be three times as thick on one side of the cone. This fine migration is enough to clog the Chemex filter and slow down the drip of water so much that it takes over ten minutes for a brew to complete (if you can even get all the water to drip out, that is). You might expect the resulting cup to be over-extracted and too strong, but in fact the opposite happens. The water hanging out in the cone for ten minutes cools down so much that it no longer has the energy to dissolve more coffee on its way through it.
Here’s my workaround: Use a spoon to spread out the bed of ground coffee up the sides of the cone as thin as possible so the water doesn’t have as far to travel to soak all the way through. Start in the center of the bed with your pour and spiral outward and upward for the bloom. You’ll know you did this properly if you don’t see any big bubbles coming up from the bed while you pour the rest of your brew water.
Once the thick filter was accounted for with enough pre-wetting and the technique described above, the resulting cup of coffee was equally as flavorful and clear as the cup from the V60. The V60, however, finishes dripping about two minutes faster. That’s why you’ll see us using Hario V60 drip cones instead of the Chemex in Corvus.