metaldwarf
Member
Rather than use a thief to check SG during fermentation, and risk contamination . Is it possible to simply place the fermenter on an accurate scale and infer from the change in weight the change in SG?
Assume we are going to make a 25L batch of beer. If we started with pure water the weight would be 25Kg. If our OG was 1.050 we essentially have wort that is 5% heavier than pure water, it should weigh in at 26.25Kg (assuming you subtract the weight of carboy, airlock etc.)
As the wort ferments there will be a loss of mass due to the escape of CO2 out the airlock. The scale should show a slow decrease in weight. We should therefore be able to infer the SG from the change in weight. Assume after a few days the scale reads 25.5KG, the mass of the wort has fallen 3% and is now only 2% higher than pure water, which means our SG should now be 1.020
Obviously there is some room for error but does this work?
Assume we are going to make a 25L batch of beer. If we started with pure water the weight would be 25Kg. If our OG was 1.050 we essentially have wort that is 5% heavier than pure water, it should weigh in at 26.25Kg (assuming you subtract the weight of carboy, airlock etc.)
As the wort ferments there will be a loss of mass due to the escape of CO2 out the airlock. The scale should show a slow decrease in weight. We should therefore be able to infer the SG from the change in weight. Assume after a few days the scale reads 25.5KG, the mass of the wort has fallen 3% and is now only 2% higher than pure water, which means our SG should now be 1.020
Obviously there is some room for error but does this work?