ASBC 2001 meeting abstract - An assessment of the effects of various exogenous enzyme additions when producing wort suitable for lager beer production from unmalted sorghum.

P-5

An assessment of the effects of various exogenous enzyme additions when producing wort suitable for lager beer production from unmalted sorghum.
DECLAN L. GOODE (1,2), Philip E. Douglas (1,2), Catherine Halbert (1,2), and Elke K. Arendt (1), (1) Department of Food Science, Food Technology and Nutrition, National University of Ireland, Cork, Ireland; (2) National Food Biotechnology Centre, National University of Ireland, Cork, Ireland.

Small-scale mashing experiments were carried out using 100% unmalted sorghum grist. The calcium content of the mash-in liquor was varied from 0 ppm to 500 ppm in order to determine the optimum calcium level of the mash system. The effects on wort quality when increasing the dosage rates of enzymes Hitempase, Bioprotease and Bioferm from 0.03-1% volume per weight (v/w) of grist were evaluated. The effects that proteolytic enzymes Bioprotease, Fungal Protease and Bioprotease Concentrate had on wort quality were assessed. Mashing was carried out using a commercial mashing program currently being used in the manufacture of sorghum lager beers. This had temperature stands at 50°C, 95°C, and 60°C. At mashing-off a range of wort parameters were evaluated. These included filterability, percentage extract, colour, pH, fermentability, total soluble nitrogen, free amino nitrogen, high molecular weight nitrogen and amino acid profiles. There was an increase in percentage extract from 0-200 ppm Calcium. At levels greater than 200 ppm calcium the percentage extract reached a plateau. An increase in the level of Hitempase gave a corresponding increase in filterability and percentage extract. An increase in the level of Bioprotease gave a corresponding increase in total soluble nitrogen, high molecular weight nitrogen and free amino nitrogen. An increase in the level of Bioferm gave a corresponding increase in filterability and apparent degree of fermentation. In comparison to the Bioprotease enzyme, Fungal Protease and Bioprotease Concentrate gave higher levels of free amino nitrogen. However, this increased proteolytic activity resulted in lower quantities of high molecular weight nitrogen. Higher levels of individual amino acids were also recorded, indicating higher peptidase activity. The potential for brewing a high quality beer from unmalted sorghum could therefore be improved by 1. Adjusting the mash-in liquor to give a calcium content of 200 ppm, 2. Adjusting the levels of Hitempase to 0.1% Bioferm to 0.1% and Bioprotease to 0.1% (v/w of grist) in order to obtain a wort that is suitable for fermentation.

Declan Goode received a Bachelor of Science Degree in Food Technology from The National University of Ireland, Cork, Ireland in 1998. He is currently in the final stages of completing a Master of Science Degree in the area of Brewing at The National University of Ireland, Cork. His thesis is entitled 'Brewing with unmalted sorghum and commercial enzymes'. He was recently appointed head brewer at the newly developed pilot scale brewing research facilities at The National University of Ireland, Cork, Ireland.