Butter is defined as a fatty product derived exclusively from milk. It is principally in the form of a water-in-oil emulsion and has a minimum milk fat content of 80%. The butter making process involves pasteurizing, ripening, churning, working, and packaging the cream. Additives like salt and coloring are often added to butter to improve qualities like flavor and shelf life. Butter is classified based on factors like acidity of cream, salt content, and intended end use.