And so ruled the Shulchan Aruch (Code of Jewish Law, Orach Chayim 475:3): "If one swallows matzah, he fulfills his obligation, but if one swallows bitter herbs, he does not fulfill his obligation, as tasting the bitterness is required, and it is not present." The Mishnah Berurah explains (sk 29): "If one swallows matzah, he fulfills his obligation - retroactively, as this too is considered eating, even though one did not chew and did not taste the flavor of the matzah. And even though above (in 473:4) we ruled that one does not fulfill his obligation by eating cooked matzah because the taste of matzah is nullified, it seems that one needs the taste of matzah, one can say that there is a difference there, because the bread itself loses the taste of matzah, but here there is a taste, only he did not feel the taste in his mouth. Nevertheless, all this is retroactive, but ideally one should chew it until one feels the taste in his mouth." And even though in essence one should chew everything and feel the taste throughout the entire eating, indeed, there is some precision in the words of the Mishnah Berurah, for it is sufficient if one begins to taste the flavor.