I am distilling. I had air bubbles every 5 seconds and a week later became every 2 and a half minutes. Do I wait till there is none whatsoever or consider it done. Thanks for the help Kris
The bubbles in the air lock are a nice confidence booster but are not a good measure of completion of fermentation. Measure the specific gravity (with a hydrometer or refractometer) at the start and then take a series of readings (say) after 10 days. If the SG is the same over a few days then the fermentation has slowed to a point where one might consider it "stopped".
A correctly made up mash of glucose and Turbo Yeast is generally finished fermenting in 7 -10 days.
I find that a good "rule of thumb" for room temperature fermentation is that they take between 7 to 10 days to "complete". Leaving the fermentation for 14 days will rarely do any harm but may be a longer time than is actually needed. If in doubt and no hydrometer is available then 10 days should be a good period of time to ensure most of the sugars are used up. If the ambient temperature is below 20C then one might increase fermentation time by a day for every 5C below 20C. Again this is a very general approximation and its always best to check with a hydrometer.
As for distillation - that subject is generally beyond this site's remit. But good luck and - reject the first 50cc as it may contain any methanol produced in the mash.