The riddle of the kitchen (5)
I believe the answer is:
sieve
'the riddle' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for sieve that I've seen before include "Eratosthenes' invention" , "Craft for Jumblies" , "particle separator" , "Colander" , "Fine riddle" .)