Production of Lager Beer from Sorghum Malt and Waxy Grits

Abstract

A trifactorial experiment with a level of confidence of P < 0.05 was performed to study lagers produced with barley or sorghum malts and a commercial source of adjuncts or refined waxy sorghum (WXSOR) grits subjected to three treatments prior to mashing: control, pressure cooking (PC-WORT), and a two-step sequential heating that consisted of cooking adjuncts at 80°C followed by pressure cooking (GEL-PC-WORT). Worts were produced following a double-mashing procedure, hopped and fermented with bottom yeast (Saccharomyces cerevisiae) in a 1-L capacity reactor. The diastatic activity level of the barley malt was 1.4 times higher than that of the sorghum malt. The barley malt produced higher yields of worts adjusted to 14°P with higher amounts of α-amino nitrogen (AAN) and similar amounts of reducing sugars compared with counterparts produced from sorghum malt. The WXSOR grits produced worts with similar yield and properties as did worts produced from commercial adjuncts, except WXSOR worts contained higher AAN. In contrast with the control and PC-WORT, the GEL-PC-WORT mash procedure produced 20% more wort yield adjusted to 14°P and contained similar pH, AAN, and reducing sugars. Barley malt beers and those produced from commercial adjuncts contained lower amounts of residual reducing sugars and higher quantities of ethanol than those produced from sorghum malt and WXSOR grits. Beers produced from GEL-PC-WORT contained the highest ethanol content and lowest reducing sugar content. This study demonstrated that it was feasible to produce 100% sorghum beers, especially when brewing grits are gelatinized and pressure-cooked before mashing.