The most common and most likely answer to this crossword clue is the 6 letter word MOCHAS
I've seen this crossword clue in Financial Times
M
O
C
H
A
S
More clues leading to the result MOCHAS
Buddy explains!

The straight part
We know that "coffees" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case coffees = mochas.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MOCHAS mean?
MOCHAS noun- A coffee drink with chocolate syrup added, or a serving thereof; a caffè mocha.
- A coffee and chocolate mixed flavour.
- A dark brown colour, like that of mocha coffee.
- A strong Arabian coffee.
- An Abyssinian weight, equivalent to a Troy grain.