i take your question that you are asking that according to halocho how much time do we need to consider that the taste had already halochakly traveled
it seams from shulchan aruch - yora deaya 92.2
(about a milk falling onto a peace of meat in a hot pot, and that if you where mixing wright away or you closed the pot right away the rest of pot combines with peace (we use the whole pot to mivatel the drop))
that it is instant (but maybe the time it takes to close the cover of a pot see below. (but it seems that the Taz (there) holds that it is instant))
rough partial translation
... if mixed from beginning (when the drop fell) ... ramo ... if he mixed (the pot) in the beginning or covered (the pot) right away the pot...
ps and when we kasher something with hagolo i understand that it is instantly kosher