We don't have a lot of information about Klingon imports (other than
the occasional case of Romulan ale and the still mysterious substances
qevaS and DIlyum). But it seems likely that they must import coffee. A
recently located short note from an interview with Maltz reveals the Klingon
word for coffee:


Okrand acknowledges that it is unclear whether this obvious cognate
refers to the beverage itself, or to the prominence of "caffeine" in the brew,
or perhaps to both at once.