This refractometer is an essential tool for anyone growing their own grapes. It takes the guesswork out of picking decisions because it can accurately measure the sugar in grapes with just 3 drops of juice from grapes on the vine. Just take a few samples from different vines and the sugar content can be determined immediately in the field.

Its use is simple. Calibrate the refractometer first using the detailed instructions provided. Then, in the field, use the suction tube to pull juice from a grape, and press the juice sample against the prism glass plate. Point the refractometer at a light source and look through the eyepiece to see the reading. Readings can also be taken during pressing.

For homebrewers, this refractometer also allows you take instant gravity readings at any point during the boil.

This refractometer has ATC (automatic temperature compensation). This feature allows the user to take a reading in different room and outdoor temperatures, without having to recalibrate the refractometer.

Once fermentation has started, the refractometer will no longer accurately read the sugar content of a sample because alcohol is now present. If you are using the refractometer for a final reading calculations are needed.

The refractometer can accurately read from 0% to 32% Brix (sugar). It comes with complete directions, an adjustable diopter, a carrying case, and sample suction tube. Length: 6.5" (16.5cm).