Currently reading The world atlas of coffee (James Hoffman)
p77 French Press
A couple of different things here compared to what you read elsewhere
- medium grind rather than coarse
- after 4 mins break the crust so it drops to the bottom, and then wait 5 mins so the finer particles sink to the bottom (then pour without plunging)
"Many people recommend pouring out the entire pot once the brew is done, to prevent grounds continuing to steep and start to overextract. If you follow the instructions above the coffee should not continue to brew or add negative flavours, so this is not necessary"
Why do the grounds stop extracting once the crust is broken and the grounds sink to the bottom?
What is the difference, in relation to extraction, if the grounds are at the top or at the bottom?
The more contact the grounds have with the water the more they will extract. There is an optimal point of time to let any beans brew which will depend on time, temp and grind coursness - at a certain point in time you begin extracting the flavored you don't want to!
Well he certainly looks authentic
This is mentioned again on p66 of the same book, in relation to "cupping":
"To end the brewing process, the layer of floating grounds on top of the bowl, called the crust, is stirred. This causes almost all of the coffee grounds to fall to the bottom of the bowl where they stop extracting. Any grounds and foam that remain on top can be skimmed off and the coffee is ready to taste [..] coffee tasters use a spoon to get a small sample of coffee...."
Keen to give this brewing process a shot rather than just a normal espresso