The must meter (or saccharometer) directly shows the percentage of sugar in kilograms, meaning the kilograms of sugar contained in 100 kilograms of must according to its density.

This instrument can determine the sugar content of the grapes and their degree of ripeness.

It can also predict the outcome of winemaking by approximately calculating the alcohol content that will be obtained from these grapes.

• The must meter is calibrated at 15°C, it does not have a thermometer.
• The temperature of either the must or the grapes should not differ significantly from this.
• For temperatures +10°C and above, the must meter shows -0.5.
• For temperatures -10°C and below, the must meter shows +5.