Here’s a handy and inexpensive piece of homebrew equipment you ought to have. This refractometer is designed for measuring the sugar content and specific gravity of liquids. This is an ATC (Automatic Temperature Compensation) Brix refractometer that includes a specific gravity scale. You won’t have to do conversions between Brix and gravity when doing measuring, you’ll get the two index in your optics. Best of all, it only requires a drop of liquid for an accurate reading. No need to sanitize a hydrometer, scoop, and test jar then lose a test jar of beer or wine in the process. In the vineyard you can simply squeeze a grape for a drop of juice to measure and see how your grapes are doing.