The most common and most likely answer to this crossword clue is the 6 letter word LIEBIG
I've seen this crossword clue in The Guardian
L
I
E
B
I
G
More clues leading to the result LIEBIG
- Old chemist’s invention of considerable importance
- Something like Bovril I used to stuff carp? Send it back!
- Pork pie of sizable dimensions for radical pioneer from Germany
- Invention by great chemist
- Chemist‘s position serious
- Fiction by great German chemist
- False information by great German chemist
- Doctor eligible, but wanting the French or the Spanish chemist
- Tell a story to eminent scientist
- Story, tall one condensed?
Buddy explains!

The straight part
We know that "German chemist" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case german chemist = liebig.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.