Review on 1 High-Quality Glass Hydrometer Testing Jar by Johnny Black

Ideal for measuring alcohol content. It's big enough to fit in a hydrometer and thin enough that it doesn't require a lot of alcohol to check like you would if you were using a bottle or similar. Do not throw the hydrometer into the vessel! I read a few comments that said the glass broke when a hydrometer was thrown in. In any case, this is not the right test. Slowly lower the hydrometer into the glass with the alcohol, pressing down slightly and then releasing. It floats back to its proper level. When inserting the hydrometer into an empty can, hold the can by the side and insert the hydrometer until it touches the bottom, then turn the can to the right.