Two paths for fermentation ingredients to secure sugar Ingredients that already contain sugar, such as fruit, honey, and milk, are fermented directly by yeast, while grains like rice or barley undergo a saccharification stage that converts starch into sugar before fermentation. Fermentation raw materials All ingredients containing carbohydrates Sugar-type ingredients Fruit, honey, milk Starch-type ingredients Rice, barley, potato Yeast added directly No additional steps Saccharification step required Amylase/Aspergillus Starch → sugar conversion Alcohol fermentation Ethanol + carbon dioxide production