Measure the alcohol content of wine before and during fermentation. The hand-held wine refractometer is used for measuring grape must concentrations. The operator needs simply to apply a sample on the prism to view the measurement value through the eyepiece. Easyand very convenient to use. Aim the front end of the refractometer to the direction of a bright light source and adjust the eyepiece until the reticle scale can be seen clearly.The reading is the Brix of the measured solution. ATC compensation range.