This refractometer is used to measure the sugar in the original grape juice, then from the scale you can know the alcohol content in the wine (made from the grape juice), by measuring the alcohol content you can ferment the grape juice (by volume) wine juice Measuring range - alcohol test 0-25% Brix test 0-40% Easy to use - place 2, 3 drops of sample on the main prism, close the plate and view the degree value through the viewing window. usage: Open the lid and carefully inspect the prism with a soft cloth. Take a few drops of the solution to be tested and place it on the detection prism. Then gently close the lid to avoid air bubbles and spread the solution over the entire prism surface. Aim the light entrance plate of the instrument to the light source or bright place, observe the field of view through the eyepiece, and turn the eyepiece to adjust the handwheel to make the blue and white boundaries of the field of view clear. The scale of the dividing line is the concentration of the solution. Calibration and temperature calibration: The instrument needs to be calibrated to zero before measurement. Take a few drops of distilled water and place it on the detection prism. Turn the zero adjustment screw to adjust the scale to 0% of the scale. Then wipe and test the detection prism. Another method (for determining sugar content only) is to use a temperature correction table and then add (or subtract) the temperature correction value to the value read at ambient temperature to get an accurate value. Colour: Black Delivery Quantity: 1 Piece