First, in (Manning & Schutze, 1999, p152-3) say
“It is a convention in English to talk about strong tea, not powerful tea, although any speaker of English would also understand the latter unconventional expression.” They go on to ask “why do we use powerful for drugs like heroin, but not for cigarettes, tea and coffee?” They posit that the distinction is important as a way to inform our society of important lessons (i.e. “strong” is OK but “powerful” must be used with caution if at all).