By far the most widespread form of fermentation is the production of alcohol. Alcoholic beverages are produced by the action of yeasts (primarily Saccharomyces cerevisiae but also many others) on sugars found in honey, grapes, apples, and many other fruits, as well as cacti, tree saps, grains, starchy tubers, and milk. Indigenous people of most regions of the world developed distinctive alcoholic beverages made from available local carbohydrate sources. Simple carbohydrates ferment directly into alcohol. Yeasts are generally present on sugar-rich substrates, and fermentation will generally proceed spontaneously. For instance, raw honey diluted with water will inevitably begin to ferment, as will freshly pressed fruit juice.