Foaming Properties of Cold Brew Coffee

Abstract

The foaming properties of cold brew coffee have been studied. The variables investigated were coffee variety, roast degree, brewing conditions, and brewing methods. The initial foam volume generated from 37.0±1.0 to 47.0±0.5 mL for light to dark roast degree coffee brews, respectively, due to the higher nitrogen content and lower surface tension of the dark roast brews than that of light roast brews. Brews from dark roast beans had more stable foam due to the higher viscosity and higher total sugar content than the light roast coffee brew. The samples were precipitated with ethanol to investigate the effects of chemical composition on the foaming properties. The reconstituted supernatant fraction presented the foam atbility due to the higher nitrogen content and lower surface tension than that of the reconstituted precipitate fraction. The reconstituted precipitate fraction exhibited foam stability due to the higher total sugar content than that of the reconstituted supernatant.