The most common and most likely answer to this crossword clue is the 6 letter word SOLERA
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More clues leading to the result SOLERA
Buddy explains!

The straight part
We know that "wine-blending process" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case wine-blending process = solera.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 SOLERA mean?
SOLERA noun- A method of producing sherry in which small amounts of younger wines stored in an upper tier of casks are systematically blended with the more mature wine in the casks below
- A large wine cask, on the bottom tier in this system, that contains the oldest wine