I received an old hydrometer for my birthday. It was made in Germany (D.R.G.M. No 1014519). It has a scale for potential alchohol, 2 other unlabled scales, and a therometer. It is labled as from 'Berg & Sons, Tacoma and Seattle. The instructions on the hydrometer tells me to ‘float tester in the brew when ready for fermentation … When tester sinks to letter B fermentation is finished and it is time to bottle. Legal limit of alcohol is 1/2 of 1%’
Anybody have any info on this, I would be glad to learn more. The hydrometer appears to be in un-used shape and is in original package.
Before anybody asks, it is not for sale.
D.R.G.M. = Deutsches Reichsgebrauchsmuster meaning that the design or function of an item was officially registered inside all of the Germany states and not only locally registered. Used 1891 to 1952.
In 1952 it was changed to Deutsches Bundesgebrauchsmuster (D.B.G.M.)
Guess they had an aversion to using “Reich” for some reason…
I have one of these hydrometers, but made in the USA. One scale is exactly double the potential alcohol scale, which I assume is potential proof? No idea what the third scale is. It’s zero point is at -1% potential alcohol and reads 28 at 13% potential alcohol…
That’s what I thought at first, too. But looking at the hydrometer I normally use, I see that a reading of 24.5 Plato (actually Brix/Balling) is at 13% potential alcohol. But it could be that the two hydrometers are using different potential alcohol scales and that it is Plato.