Natural coffee flavor by fermentation

A process for producing a natural buttery flavor, winey flavor or combination buttery and winey flavor of which diacetly and acetoin are the major flavor constituents from a coffee substrate which comprises:

• (a) forming a nutrient media containing water and soluble coffee solids as the sole nutrient component, said soluble coffee solids concentration of at least 0.5%;
• (b) adding a diacetyl producing microorganism which is either a strain of lactic acid producing bacteria or yeast to said nutrient media, wherein said microorganism will ferment the coffee solids to produce said natural flavor;
• and
• (c) mixing the microorganism and nutrient media of step (b) and allowing said microorganism to ferment in the mixture for a period of time effective to produce diacetyl at a pH of from 4.0 to 7.0 and a temperature of from 16.degree. to 37.degree. C. under aeration conditions wherein the nutrient media contains sufficient oxygen to allow for diacetyl production during said fermentation to produce a fermented coffee substrate containing sufficient diacetyl and acetoin to provide said flavor.