Testing your honey for moisture and grading it for color are important to do when selling your honey at a larger volume. A refractometer’s job is to measure the percent moisture in honey. This level can vary from batch to batch but typically does not want to go above 17%.
Color grading can be important too, especially if selling to someone (a baker or mead maker) who is looking for a particular color (and thus flavor) of honey. Typically the darker the honey, the more robust the flavor.
Ways to ensure your honey is “ripe” (at the right moisture content):