My hydrometer arrived today (would you believe that no-one stocks them over here?!) and warmed the meth to 20c. Plopped the hydrometer into the sample, and it just sank straight to the bottom! It's a brewer's/winemaker's one, have I fkd up?
So I decided to weigh a sample. Given that a litre should weigh 794g, my 100ml sample weighed 84g but over a 15 minute period went down to 80g. I did this twice, with the same result.
Answers on a postcard please......
Sounds like the battery in your scales needs replacing if it changes over time.
The hydrometer sinking suggests it's pure enough to me. Mine is an alcohol hydrometer and if it sinks, I know it's good to re-use.
I did some tests with fresh Meth (not reclaimed) and it sank in that, but if I added 1ml of water to the 100ml sample then the hydrometer would rise.