Mainly designed to measure, monitor and control the sugar content in original grape juice and alcohol-content by volume of the grape wine made from the fermented grape juice and sugar concentration in the grapes. Simply manufacture a distillate of the liquids to be measured, and then place the distilled sample on the prism and you'll get the result in a second. Ideal for field use - the refractometer has ATC (Automatic Temperature Compensation) for precise measurement without having to re-calibrate after changes in ambient working temperature. This refractometer can be used for the still raw or before and after manufactured finished product just as long as the sample to be tested is distilled.