What tool is used to determine the ripeness of table grapes?

The refractometer is the appropriate tool for determining the ripeness of table grapes because it measures the sugar content of the grape juice. As grapes ripen, their sugar concentration increases, which is a key indicator of quality and readiness for harvest. By placing a few drops of grape juice on a refractometer, one can obtain a Brix reading, which reflects the percentage of sugar in the juice. Higher Brix values generally indicate that the grapes have reached optimal sweetness for eating.

In contrast, while a hydrometer measures the density of liquids and could provide some sugar content information, it is not specifically designed for evaluating fruit ripeness. A pH meter is used to measure the acidity of solutions, which is important for assessing the flavor profile but does not directly indicate ripeness. Lastly, a soil tester is focused on examining soil properties such as pH, nutrient content, and moisture levels, which are not directly related to the ripeness of the grapes themselves.