A fermentation starter (called simply starter within the corresponding context, sometimes called a mother) is a preparation to assist the beginning of the fermentation process in preparation of various foods and alcoholic drinks. Food groups where they are used include breads, especially sourdough bread, and cheese. A starter culture is a microbiological culture which actually performs fermentation. These starters usually consist of a cultivation medium, such as grains, seeds, or nutrient liquids that have been well colonized by the microorganisms used for the fermentation.
These starters are formed using a specific cultivation medium and a specific mix of fungal and bacterial strains.