Well, boil the wort AFTER the grain has been mashed and sparged. I've never used a Vacola before, i just have one hanging around, and was just wondering if it would get up to 64-70 C. for mashing and could then be used to boil the resulting wort to denature the enzymes.
If it did, then i wonder if it would be a convenient piece of equipment? (i don't have a large pot yet, or something to mash/sparge in and just looked at the vacola the other day and thought "maybe...."
-Cheers