Since my last review of the BeerBug hydrometer I’ve had a chance to do some more testing. At first the data was pretty poor. I sent those results to the BeerBug folks who thought it might be because the device wasn’t level. It seems pretty sensitive to this, as it couldn’t have been more than few degrees off.
I got a stick-on bubble level like this one, re-tared, and left it for a couple of days in some santizer solution (approximately SG 1.00 and with the taring should read 1.000 regardless). The results were much better than I’d seen before:
There is still a little drift that seems to be temperature related. The indicated specific gravity varied from about 0.999 to 1.007. Probably because I tared at a time when the temperature was relatively low, the drift is mostly at the upper end. It would be better to tare at the average fermentation temperature.
As usual, I have a batch of beer just coming out of primary so it will be a while before I can test it under actual conditions, but I think if it the device is kept level it will work well enough to ascertain the end of primary fermentation.