Mashing Studies with Unmalted Sorghum and Malted Barley

Self Cite

Pilot scale (1000 L) brews were carried out with a grist comprising of unmalted sorghum (50% of total wet weight of grain) (South African variety) and malted barley (50% of total wet weight of grain) grist using a mashing program with rests at 50°C, 95°C and 60°C. Mashes were supplemented with a high heat stable bacterial ␣-amylase, a bacterial neutral protease and a fungal ␣-amylase. A control brew containing 100% malted barley was also carried out. Saccharification difficulties were encountered during mashing, and extraction of the grist was lower for the sorghum mashes. The sorghum mashes showed comparable lautering behaviour to that of the control mash. At mashing off the sorghum worts were starch positive. Apparent degree of fermentation of the sorghum gyles were less than the control gyles. Green beer filtration proved unproblematic. The sorghum beers compared quite closely with the control beer with regard to colour, pH and colloidal stability. Foam stability deficiencies were apparent with the sorghum beer. However, the fermentability of the sorghum worts were lower. Hence the sorghum beers were lower in total alcohol. Sensory analysis indicated that no significant differences existed between the sorghum beer and both the control beer and a commercial malted barley beer with regard to aroma, mouth-feel, after-taste and clarity. However, the sorghum beer was found to be significantly different to both of the other beers with regard to colour, initial taste and foam stability.

Section: -2863(9'8-32mentioning

confidence: 97%

Section: -2863(9'8-32mentioning

confidence: 99%

Section: -2863(9'8-32mentioning

confidence: 99%

Section: %8)6-%07 %2( 1)83(7 1exivmepwmentioning

confidence: 99%

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Pilot Scale Production of a Lager Beer from a Grist Containing 50% Unmalted Sorghum

Goode

Arendt

2003

Self Cite

“…This is indeed one of the major problems encountered in mashing with some malted sorghum cultivars [3][4][5]8,9,13,14,17,18,21 . However, it is known that acceptable worts for beer brewing can be obtained from 100% unmalted sorghum by supplementing the mashes with optimal amounts of thermostable α-amylase, fungal α-amylase and bacterial proteases 11 . In contrast, what is not known is the effect of singular or combined contributions of these enzymes on starch liquefaction of unmalted sorghum grains.…”

Section: Introductionmentioning

confidence: 99%

Modelling and Optimizing of Mashing Enzymes - Effect on Yield of Filtrate of Unmalted Sorghum by Use of Response Surface Methodology

Desobgo

Nso

Tenin

et al. 2010

J. Inst. Brew. 116(1), 62-69, 2010The effect of commercial enzymes on liquefaction of starch from unmalted sorghum was studied. The effects which these enzymes had on rates of filtration were evaluated. Models were developed, validated and optimized to establish the actions of enzymes, either alone or in combination. Preliminary studies on the sorghum cultivars Safrari, Madjeru and S.35 showed that α-amylase was the backbone enzyme for starch liquefaction among the enzymes used (α-amylase, Filtrase, protease and β-amylase). Models confirmed this observation as α-amylase individually in its first order (X 1 ) contributed 25, 11 and 17%, and in its sum of first and second orders (X 1 +X 1 2 ) contributed a 29, 31 and 36% yield of filtrate for Safrari, Madjeru and S.35 respectively. The ease of starch liquefaction, assessed by summing the first and second orders of individual intervention of all enzymes, was found to be in the order of Madjeru, S.35 and Safrari (79, 70 and 56% of yield of filtrate respectively). The importance of the enzyme combination in starch liquefaction in Safrari, S.35 and Madjeru was shown to be 44, 30 and 21% respectively. Enzyme combinations giving maximal starch liquefaction, as identified from a Doehlert experimental matrix, displayed a similar yield of filtrate (Safrari: 85 mL, Madjeru: 84 mL and S.35: 81 mL) after filtration of a 130 mL mash during 1 h. Validation of t he models revealed the model developed for Madjeru was the most reliable (R 2 = 0.994), while those developed for Safrari (R 2 = 0.987) and S.35 (R 2 = 0.976) were slightly less reliable. Model optimization gave theoretical enzyme (Brewers Amyliq TS, Filtrase NLC, Brewers Protease and β-amylase) combinations of 25 mg, 5.68 mg, 100 mg and 67.

Impact of Dark Specialty Malts on Extract Composition and Wort Fermentation

Coghe

D'Hollander

Verachtert

et al. 2005

Dark specialty malts are important ingredients for the production of several beer styles. These malts not only impart colour, flavour and antioxidative activity to wort and beer, they also affect the course of wort fermentations and the production of flavouractive yeast metabolites. The application of considerable levels of dark malt was found to lower the attenuation, mainly as a result of lower levels of fermentable sugars and amino acids in dark wort samples. In fact, from the darkest caramel malts and from roasted malts, practically no fermentable material can be hydrolysed by pilsner malt enzymes during mashing. Compared to wort brewed with 50% pilsner malt and 50% dark caramel malt or roasted malt, wort brewed with 100% pilsner malt contained nearly twice as much fermentable sugars and amino acids. Reduced levels of yeast nutrients also lowered the fermentation rate, ranging from 1.7°P/day for the reference pilsner wort of 9 EBC to 1.1°P/day for the darkest wort (890 EBC units), brewed with 50% roasted malt. This additionally indicates that lower attenuation values for dark wort are partially due to the inhibitory effects of Maillard compounds on yeast metabolism. The application of dark caramel or roasted malts further led to elevated levels of the vicinal diketones diacetyl and 2,3-pentanedione. Only large levels of roasted malt gave rise to two significant diacetyl peaks during fermentation. The level of ethyl acetate in beer was inversely related to colour, whereas the level of isoamyl acetate appeared to be affected by the use of roasted malt. With large levels of this malt type, negligible isoamyl acetate was generated during fermentation.