Kvasny Prum. 2004; 50(10): 298-301 | DOI: 10.18832/kp2004020

Effect of trub, oxygen content and hopped wort pH on the course of fermentation.Peer-reviewed article

Mariana CVENGROSCHOVÁ, Gabriela ŠEPEĽOVÁ, Daniela ŠMOGROVIČOVÁ

¹ Pivovar Šariš a. s., Pivovarská 9, 082 21 Veľký Šariš, Slovenská republika

² Katedra biochemickej technológie, Fakulta chemickej a potravinárskej technológie STU, Radlinského 9, 812 37 Bratislava, Slovenská republika

The effects of the properties of hopped worts on the course of fermentation
and beer character were monitored in this work. Hopped
wort pH in the range of 5,1-5,4 has insignificant effects on the speed
of primary fermentation, the breakdown of diacetyl was faster in case
of hopped worts with pH = 5,1 (6,9 days), the slowest diacetyl breakdown
was observed for hopped worts with pH = 5,4 (11,4 days). From
organoleptic point of view, finished beers prepared from hopped worts
with 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 yeast
removal from cylindro-conical fermenters, decrease in diacetyl content
as well as the number of dead yeast cells (to 2 %) were comparable.
In case of hopped worts with a higher trub content, 1 day longer
breakdown 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 in
the organoleptic properties of fresh beers. In case of infusion mashing,
a higher haze level at the angle of 90° and a lower haze level
at the angle of 15° were observed in unhopped wort. In hopped
wort, a higher haze level in case of infusion mashing as well
as during decoction mashing at the angle of 90° and 15° was observed.The effects of the properties of hopped worts on the course of fermentation
and beer character were monitored in this work. Hopped
wort pH in the range of 5,1-5,4 has insignificant effects on the speed
of primary fermentation, the breakdown of diacetyl was faster in case
of hopped worts with pH = 5,1 (6,9 days), the slowest diacetyl breakdown
was observed for hopped worts with pH = 5,4 (11,4 days). From
organoleptic point of view, finished beers prepared from hopped worts
with 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 yeast
removal from cylindro-conical fermenters, decrease in diacetyl content
as well as the number of dead yeast cells (to 2 %) were comparable.
In case of hopped worts with a higher trub content, 1 day longer
breakdown 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 in
the organoleptic properties of fresh beers. In case of infusion mashing,
a higher haze level at the angle of 90° and a lower haze level
at the angle of 15° were observed in unhopped wort. In hopped
wort, a higher haze level in case of infusion mashing as well
as during decoction mashing at the angle of 90° and 15° was observed.

Keywords: fermentation, hot break, cold break, oxygen, hopped wort, pH

Published: October 1, 2004