Application of Palm Wine Yeast Species in Beer Brewing

Abstract

Brewing is found to be one of the lucrative businesses in Nigeria. The brewer’s yeast commonly known as Saccharomyces cerevisiae is always imported and its price affects the price of the products drastically. In this work, yeast strain was isolated from Palm Wine, identified as Saccharomyces cerevisiae and used as an alternative in beer brewing. The isolate (SPW) was seen to poses many similar characteristics of the brewer’s yeast (SCT) imported from foreign countries. The isolated and enriched yeast was employed in the laboratory for the production of beer. Results showed that both organisms failed to ferment melibiose and raffinose but fermented glucose, maltose, fructose, sucrose, and galactose. They survived at stress conditions for temperature and cell osmotic pressure in high concentration of ethanol and sugar. They showed good flocculation ability of 97%, and 82% respectively. Their percentage viability was 96.66% and 91.00% respectively with no production of hydrogen sulfide gas. The property of wort prepared for brewing was; pH of 5.82, specific gravity of 1.050 and iodine reaction showed yellow colour. After fermentation, the specific gravity was 1.001 and 1.010 for SPW and SCT respectively while alcohol content was 6.53% and 5.25% respectively. Wort was fermented at 28 ± 2oC for six days and the product beer showed apparent extract of 3.4oP and 4.8oP, Real extract of 4.8oP and 6.55oP, real degree of fermentation of 58.44% and 61.22% for SPW and SCT respectively. Statistical analysis showed that yeast strain isolated from palm wine after enrichment had great potential when compared to brewer’s yeast strain in beer production attributes (p < 0·05).