In the last post, I spoke about the issues involved with making tea on Shabbat, and in this post I want to talk about coffee -- specifically the French press.
The major concerns about coffee and tea on Shabbat that Mr. T and I considered were borer (separating) and bishul (cooking). The latter is forbidden on Shabbat and the former is allowed only when you're removing the good from the bad, or the desirable from the undesirable. That is, you can pick cashews out of a bowl of mixed nuts, but you can't remove all the mixed nuts to get to the cashews.
Instant coffee is the no-brainer of coffee drinking on Shabbat, because it's already cooked and in Judaism there is a law of "no cooking after cooking" (ein bishul acher bishul), which means that once something is cooked, you're never "recooking" it on Shabbat. Instant coffee is just hot water from the urn in a cup plus instant coffee (for more, see Mishneh Berurah 318:39).
When thinking about the French press, my initial thought was that by pushing the plunger down, you're removing the bad from the good. Mr. T, in all of his genius, pointed out that you're really just moving it out of the way, like if you push around the peanuts and almonds to find more cashews to pick out of the bowl. Pushing the coffee grounds downward in a French press is completely allowed, and when you're pouring the coffee out of the French press into a cup, you're actually taking the good away from the bad. So borer isn't an issue, is bishul?
Much like instant coffee, regular old coffee grounds used in a French press are roasted, and if you apply "no cooking after cooking," then there also should be no issue, right? There's a concept that is mentioned in the Shulchan Aruch (318:5) that "there is cooking after baking" (yesh bishul achar afiyah), and some consider "roasting" to be baking and not cooking. Even if you want to hold to this more stringent opinion, just make sure you pour the hot water from your urn or hot water pot into the French press before you add the coffee, making the French press a kli sheni (second vessel), and all is right in the world since there is no cooking in a kli sheni (ein bishul bekli sheini).
So I shall enjoy my coffee on Shabbat, my quality coffee on Shabbat, in the giant Bodum French press that Mr. T has even though he doesn't drink coffee.