2. What kinds of fementable plant substances are available for commercial producers that are currently not being used, or are being used poorly, perhaps with low-quality feed-stock? Globally there is great diversity of starchy and sweet fruits, seeds, roots, and leaves, there is a very large supply of potentially fermentable products. Using selected strains of yeast, samples of candidate plant parts are being experimentally fermented and tested as potential new foods and beverages.