What is the recommended tool for testing navel maturity?

The recommended tool for testing navel maturity is the citrus press. This tool is utilized in the process of extracting juice from citrus fruits, which is crucial for assessing navel maturity. The juice extracted can be analyzed for various quality indicators, including soluble solids content and sugar levels, which are key factors in determining the maturity of citrus fruits.

While the other tools have their specific applications—such as the refractometer for measuring sugar concentration, the hydrometer for measuring the specific gravity of liquids, and the pH meter for assessing acidity—the citrus press is particularly relevant in the context of directly assessing navel oranges. The direct juice extraction allows for more immediate and practical evaluation of the fruit's maturity, which is an essential aspect in determining its readiness for harvest and consumption.