September can be an anxious time, waiting for sloes to ripen. Will you get there first, or Someone Else who also has a gin bottle begging to be filled? Ideally you should pick them after the first frost, but the sloes I've used have never been frosted and I just don't believe the end result could taste any better.
However, you can freeze sloes before using. This not only simulates frost, but makes the fruit split, which means that you don’t have to prick them all over with a needle before dropping them in the gin.
The Diversity Website comes up trumps, as usual, with straightforward instructions.
You’ll also find a recipe for Sloe Sherry, reusing the sozzled fruit after the gin’s been decanted. I can’t wait.