Tevilat keilim for the moka pot and the espresso machine, the milk-and-meat status of the coffee cup, and the cup of coffee as an act of kibud av va’em — and what hilchot niddah says about serving it.
Shevet HaLevi 10:156:2 rules that the mitzvah of kibud av vaem applies here: parental instructions regarding health-based restrictions on food and drink are binding.
OU Torah Dalet Amot of Halacha (R. Enkin, 2025).
The core question is whether making coffee constitutes mezigah — explicitly prohibited — or a maaseh avdus exempted by the Rishonim. Shabbala"l (s"k 74) holds it is mezigah and forbidden; Gufei Halacha extends this to mixing instant coffee (kaaoo). The lenient view (Divrei Yatziv, Baer Moshe) relies on the Rishonim exemption for servile acts, supported by Chazon Ish. Grishza rules the minhag is to be lenient. Gar"i Berkovits draws a practical line: sequential preparation (water, then instant, sugar, milk) is permitted; handing over a ready cup is not.
Pouring a ready beverage is classic mezigah. Building a cup of instant coffee sequentially (water, powder, sugar, milk) is preparation/cooking, not serving, and falls under maaseh avdus or is otherwise exempt. Gar"i Berkovits confirmed this in writing (michtav b'mail). Practical upshot: instant coffee preparation is more permissible than pouring brewed or ready-made coffee.
Water/coffee absorbing a secondary taste from a clean, not-used-today meat pot is nat bar nat (a weakened secondary taste) and aged taste (notein ta'am lifgam), leaving room for leniency in need; actual non-kosher absorption remains forbidden.
The Keurig machine is a composite device: most of its parts are plastic (generally exempt from tevila per most poskim). The parts that may be subject to tevila are: (1) the metal chamber/reservoir in which water is heated, and (2) the metal tube that transfers water into the cup. The machine's use is entirely via electric power and it is stationary — both factors that bear on whether it qualifies as a "כלי" requiring tevila. The responsum identifies 5 specific eitzot (practical workarounds) for those who wish to be mehader, each with its own analysis. The overall conclusion is that the main halachic position exempts the machine, but mehadrin should immerse the applicable metal components without a bracha.
Kovetz Etz Chaim vol.26 (Bobov) — R. Shlomo Halevi Efal, Boro Park. Discusses the Keurig specifically but applies to all similar pod/capsule coffee machines. Five eitzot enumerated in the body of the responsum (not fully reproduced here — see original).
Metal (and glass) food utensils acquired from a non-Jew require immersion. A grinder processes the food itself (like a pepper mill, which is obligated), whereas a measuring vessel merely holds beans that will be further processed, so it is exempt. The doubt about the mill yields immersion without a beracha.