The most common and most likely answer to this crossword clue is the 9 letter word WHEATMEAL
I've seen this crossword clue in The Times
W
H
E
A
T
M
E
A
L
More clues leading to the result WHEATMEAL
Buddy explains!

The straight part
We know that "sort of loaf" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sort of loaf = wheatmeal.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 WHEATMEAL mean?
WHEATMEAL noun- Flour or meal derived from whole grains of wheat, often not finely ground.