There are several tuber quality factors that dictate the value of the potato crop and which growers should be familiar with. Some of these factors are influenced by the grower and others are affected by the environment. The grade and size of the tubers is influenced by almost every decision in managing the production system. From variety selection to spacing, fertility, irrigation, and storage, the grade quality can be changed at any point. There are three United States Department of Agriculture (USDA) standards for potatoes: fresh potatoes; processed potatoes; and seed potatoes. Specific gravity is the density of a potato tuber or any other object relative to the density of water at a given temperature. There are basically three methods that have been or are being used by the industry for determining the specific gravity of potato tubers. They are: hydrometer, weight in air/weight in water, and salt brine solutions.