weaselchew
Well-Known Member
I tried doing a search but wasn't very fruitful given some of the common words. I'm curious if anyone has tried estimating alcohol content by weighing the entire fermenter?
As a bit of an experiment, I thought I'd sit the carboy on a fairly accurate (.05 lb resolution) digital scale during fermentation. The total weight of my 5.5 gallon batch (including the 6.5 gallon carboy) was 64.9 lbs right after I popped the airlock on. 24 hours later, the total weight is now 63.5 lbs.
I should have weighed my empty carboy to get a tare weight, but this idea didn't even come to me until after I started filling it. From what I've seen, a 6.5 gallon carboy weighs about 15 lbs. I'm using 8.33 lbs as the weight of water per gallon, which isn't exact, but just as a test I figured it was close enough. The temperature of the batch is within 2 degrees of when I first weighed it, but I haven't taken that into account either. I started playing with some calculations and this is what I came up with:
((64.9 - 15) / 5.5) / 8.33 = 1.08916294 (My OG was 1.084, so this is actually pretty close)
And now the batch is at 63.5 lbs, so:
((63.5 - 15) / 5.5) / 8.33 = 1.05860526
The difference of which should mean it's roughly about 4.0% right now. Sound correct? Or have I completely lost it?
I'm still obviously going to take some actual samples to measure with my hydrometer, but I thought I'd see how close the scale would be.
As a bit of an experiment, I thought I'd sit the carboy on a fairly accurate (.05 lb resolution) digital scale during fermentation. The total weight of my 5.5 gallon batch (including the 6.5 gallon carboy) was 64.9 lbs right after I popped the airlock on. 24 hours later, the total weight is now 63.5 lbs.
I should have weighed my empty carboy to get a tare weight, but this idea didn't even come to me until after I started filling it. From what I've seen, a 6.5 gallon carboy weighs about 15 lbs. I'm using 8.33 lbs as the weight of water per gallon, which isn't exact, but just as a test I figured it was close enough. The temperature of the batch is within 2 degrees of when I first weighed it, but I haven't taken that into account either. I started playing with some calculations and this is what I came up with:
((64.9 - 15) / 5.5) / 8.33 = 1.08916294 (My OG was 1.084, so this is actually pretty close)
And now the batch is at 63.5 lbs, so:
((63.5 - 15) / 5.5) / 8.33 = 1.05860526
The difference of which should mean it's roughly about 4.0% right now. Sound correct? Or have I completely lost it?
I'm still obviously going to take some actual samples to measure with my hydrometer, but I thought I'd see how close the scale would be.