Stevenson Reeves Triple Scale Hydrometer for Home Brewing and Winemaking (S1011) Measures specific gravity between 0.980 and 1.120, dissolved sugar in grammes per litre and a potential alcohol scale for wines. The glass hydrometer is 23cm long to float in a 100ml sample. It comes packed in a strong clear plastic tube for storage and protection. This hydrometer will show you: the starting gravity and sugar content of your beer wort or wine must; the progress of fermentation, by gradually sinking as the sugar turns into alcohol; whether fermentation has stopped too early; when to bottle or keg. Take readings at the beginning and end of fermentation to determine alcohol content.