A question about rumpots...

It appears that some people here have experience with rumpots.
Some of the recipes I have indicate that the fruit inside is actually
fermenting.
I was under the impression that yeast can't exist when alcohol gets
toward the 20% mark. Rum is generally around 80 proof (40%).
Does the juice from the fruit dilute the run enought that actual
fermantation
can start, or is the recipe wrong?

Thanks for any insights.



--
Bob Becker

www.becker.org