Fumaric Acid

used as a partial substitute for additions of tartaric acid because it tends to inhibit malo-lactic fermentation when used in the range of 1.5 to 5.7 grams per gallon (achieving an increase of 0.05 to 0.15% acidity).

It helps not only to preserve malic acid in wines but also to reduce sulphur dioxide levels and inhibit the growth and activity of lactic acid bacteria. It comes in the form of a fine, odourless, mixed grain powder.