In close proximity to the harvest it is very important to know the grapes alcohol content to determine the optimal timing for collection. The fastest way to keep track of the sugar content in the must is by using a hand refractometer.
This device, widely used in agriculture, allow us to measure the liquids refraction index. This instrument has a prism inside where the liquid is placed and directing it to the light it is possible to have a direct reading as it contains in its interior a scale of degrees.
To use the refractometer on the field, we take some grapes from different parts of the vineyard and from different parts of the cluster. We crush the grapes and the resultant must is placed on the refractometer prism, we carefully close the cover and looking through it with the light in front we will find out the sugar contained in our must.
Not doubt, a very useful device to supervise in situ our grapes stage of ripening.