fermentable adjective 1noun 1forms 3 adjective1 •Able to ferment or be fermented.“You need to convert the starches in the corn into fermentable sugars,” the always entertaining Mr. Calagione said by phone from his headquarters in Rehoboth Beach. — 2009 noun1 •Any substance that can be fermented. formsfermentables · more fermentable · most fermentable