Effect of trub, oxygen content and hopped wort pH on the course of fermentation.

Autor: Mariana CVENGROSCHOVÁ, Gabriela ŠEPEĽOVÁ, Daniela ŠMOGROVIČOVÁ
Jazyk: Czech<br />English
Rok vydání: 2004
Předmět:
Zdroj: Kvasný průmysl, Vol 50, Iss 10, Pp 298-301 (2004)
Druh dokumentu: article
ISSN: 0023-5830
2570-8619
DOI: 10.18832/kp2004020
Popis: The effects of the properties of hopped worts on the course of fermentationand beer character were monitored in this work. Hoppedwort pH in the range of 5,1-5,4 has insignificant effects on the speedof primary fermentation, the breakdown of diacetyl was faster in caseof hopped worts with pH = 5,1 (6,9 days), the slowest diacetyl breakdownwas observed for hopped worts with pH = 5,4 (11,4 days). Fromorganoleptic point of view, finished beers prepared from hopped wortswith a higher pH were preferred.With different wort aeration (8 mg/l, 9 mg/l and 10 mg/l of oxygen),no differences were observed during fermentation. The day of yeastremoval from cylindro-conical fermenters, decrease in diacetyl contentas well as the number of dead yeast cells (to 2 %) were comparable.In case of hopped worts with a higher trub content, 1 day longerbreakdown of vicinal diketones (diacetyl) to the value required,lower foam stability (by 5 s - 2 %) and a lower colloidal stability(approx. by 3 weeks - 9 %) were observed, but no differences inthe organoleptic properties of fresh beers. In case of infusion mashing,a higher haze level at the angle of 90° and a lower haze levelat the angle of 15° were observed in unhopped wort. In hoppedwort, a higher haze level in case of infusion mashing as wellas during decoction mashing at the angle of 90° and 15° was observed.The effects of the properties of hopped worts on the course of fermentationand beer character were monitored in this work. Hoppedwort pH in the range of 5,1-5,4 has insignificant effects on the speedof primary fermentation, the breakdown of diacetyl was faster in caseof hopped worts with pH = 5,1 (6,9 days), the slowest diacetyl breakdownwas observed for hopped worts with pH = 5,4 (11,4 days). Fromorganoleptic point of view, finished beers prepared from hopped wortswith a higher pH were preferred.With different wort aeration (8 mg/l, 9 mg/l and 10 mg/l of oxygen),no differences were observed during fermentation. The day of yeastremoval from cylindro-conical fermenters, decrease in diacetyl contentas well as the number of dead yeast cells (to 2 %) were comparable.In case of hopped worts with a higher trub content, 1 day longerbreakdown of vicinal diketones (diacetyl) to the value required,lower foam stability (by 5 s - 2 %) and a lower colloidal stability(approx. by 3 weeks - 9 %) were observed, but no differences inthe organoleptic properties of fresh beers. In case of infusion mashing,a higher haze level at the angle of 90° and a lower haze levelat the angle of 15° were observed in unhopped wort. In hoppedwort, a higher haze level in case of infusion mashing as wellas during decoction mashing at the angle of 90° and 15° was observed.
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