Description text

The biomass feedstock contains complex carbohydrates called cellulose, hemicellulose, and lignin. Acid (3) turns the hemicellulose into a syrup (4) made of sugars that have five carbon atoms per molecule. Once the syrup is fermented (with the aid of a special bacterium), it goes to the beer well, with a concentration of alcohol between 3 and 5 percent.