Sorghum Malts for the Production of a Lager Beer

Abstract

The major difficulties encountered when producing a lager beer with sorghum malt were investigated. Forty-nine sorghum cultivars of various origins were evaluated for Aspergillus contamination, mycotoxins, α- and β-amylases, and β-glucanases after malting. More than 60 sorghum malt samples were used in a laboratory-scale brewery, and the major wort characteristics were analyzed. The data clearly demonstrated that the cultivar (and, presumably, the growth location) had an effect in determining saccharification, filtration speed, diastatic power, and wort amino acid content. Saccharification problems were attributable to the great variability of starch gelatinization temperature and viscosity and to the lack of β-amylase in most of the cultivars. The level of amino acids in the wort depended strongly on the water content at steep-out. Also important was the wort amino acid profile, which is quite different from the amino acid profile of barley malt worts. A much higher first group-second group amino acid ratio was observed in sorghum wort. Under these conditions, the uptake of amino acids by yeast was disturbed, and a concomitant high production of vicinal diketones occurred during fermentation. All of these drawbacks can be remedied by selecting “brewing” sorghum cultivars, adapting the brewing procedure, and using appropriate brewing equipment.

• Aflatoxin
• Barley
• Enzymes
• Malt
• Sorghum
• Wort composition

View correction statement:

Erratum