Effects of aeration on flavor compounds in immobilized primary fermentation

Ilkka Virkajärvi, Katri Lindborg, Jukka Kronlöf, Esko Pajunen

Research output: Contribution to journalArticleScientificpeer-review

12 Citations (Scopus)

Abstract

Continuous immobilized primary fermentation has been studied since the last century, but has not yet fulfilled expectations. There are two main biological difficulties for continuous primary fermentation: achieving and maintaining the desired flavor and preventing contaminations. One traditional way of controlling the flavor of beer is by aeration of wort prior to pitching. We explored the effects of aeration in immobilized primary fermentation. The fermentation system used consisted of two packed bed reactors and a buffer tank between the reactors. An industrial wort and an industrial brewer's yeast strain were used. The wort was aerated by mixing air into the wort stream just before the inlet of the first reactor (pre-column). The air was diluted with carbon dioxide and both were filtered twice through a PTFE 0,2 μm membrane (domnick hunter Ltd., Durham, UK). The feed rates of synthetic air and carbon dioxide were changed independently according to a Box-Hunter experimental design while keeping the feed rate of the wort constant. The results were analyzed using a computer program for experimental design Modde 3.0, (Umetri AB, Uppsala, Sweden) and mathematical models for the concentrations of higher alcohols and two acetate esters in the out-flow from the pre-column were created. It was found that both low air feed and high air feed with low carbon dioxide feed stimulated the 3-methyl butyl acetate production in the pre-column. The main column seemed to even out the changes in the aroma compounds analyzed, so that their final levels were relatively insensitive to air supply in the range studied.
Original languageEnglish
Pages (from-to)9-28
Number of pages20
JournalMonatsschrift für Brauwissenschaft
Volume52
Issue number1
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

Fingerprint

flavor compounds
wort (brewing)
aeration
Fermentation
Air
fermentation
air
Carbon Dioxide
carbon dioxide
Research Design
flavor
experimental design
acetates
brewers yeast
boxes (containers)
Polytetrafluoroethylene
beers
odor compounds
Sweden
Saccharomyces cerevisiae

Keywords

  • flavor

Cite this

Virkajärvi, I., Lindborg, K., Kronlöf, J., & Pajunen, E. (1999). Effects of aeration on flavor compounds in immobilized primary fermentation. Monatsschrift für Brauwissenschaft, 52(1), 9-28.
Virkajärvi, Ilkka ; Lindborg, Katri ; Kronlöf, Jukka ; Pajunen, Esko. / Effects of aeration on flavor compounds in immobilized primary fermentation. In: Monatsschrift für Brauwissenschaft. 1999 ; Vol. 52, No. 1. pp. 9-28.
@article{f98c021e56a34737b10694d1ca2e3eb6,
title = "Effects of aeration on flavor compounds in immobilized primary fermentation",
abstract = "Continuous immobilized primary fermentation has been studied since the last century, but has not yet fulfilled expectations. There are two main biological difficulties for continuous primary fermentation: achieving and maintaining the desired flavor and preventing contaminations. One traditional way of controlling the flavor of beer is by aeration of wort prior to pitching. We explored the effects of aeration in immobilized primary fermentation. The fermentation system used consisted of two packed bed reactors and a buffer tank between the reactors. An industrial wort and an industrial brewer's yeast strain were used. The wort was aerated by mixing air into the wort stream just before the inlet of the first reactor (pre-column). The air was diluted with carbon dioxide and both were filtered twice through a PTFE 0,2 μm membrane (domnick hunter Ltd., Durham, UK). The feed rates of synthetic air and carbon dioxide were changed independently according to a Box-Hunter experimental design while keeping the feed rate of the wort constant. The results were analyzed using a computer program for experimental design Modde 3.0, (Umetri AB, Uppsala, Sweden) and mathematical models for the concentrations of higher alcohols and two acetate esters in the out-flow from the pre-column were created. It was found that both low air feed and high air feed with low carbon dioxide feed stimulated the 3-methyl butyl acetate production in the pre-column. The main column seemed to even out the changes in the aroma compounds analyzed, so that their final levels were relatively insensitive to air supply in the range studied.",
keywords = "flavor",
author = "Ilkka Virkaj{\"a}rvi and Katri Lindborg and Jukka Kronl{\"o}f and Esko Pajunen",
year = "1999",
language = "English",
volume = "52",
pages = "9--28",
journal = "BrewingScience",
issn = "1866-5195",
publisher = "Fachverlag Hans Carl",
number = "1",

}

Virkajärvi, I, Lindborg, K, Kronlöf, J & Pajunen, E 1999, 'Effects of aeration on flavor compounds in immobilized primary fermentation', Monatsschrift für Brauwissenschaft, vol. 52, no. 1, pp. 9-28.

Effects of aeration on flavor compounds in immobilized primary fermentation. / Virkajärvi, Ilkka; Lindborg, Katri; Kronlöf, Jukka; Pajunen, Esko.

In: Monatsschrift für Brauwissenschaft, Vol. 52, No. 1, 1999, p. 9-28.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Effects of aeration on flavor compounds in immobilized primary fermentation

AU - Virkajärvi, Ilkka

AU - Lindborg, Katri

AU - Kronlöf, Jukka

AU - Pajunen, Esko

PY - 1999

Y1 - 1999

N2 - Continuous immobilized primary fermentation has been studied since the last century, but has not yet fulfilled expectations. There are two main biological difficulties for continuous primary fermentation: achieving and maintaining the desired flavor and preventing contaminations. One traditional way of controlling the flavor of beer is by aeration of wort prior to pitching. We explored the effects of aeration in immobilized primary fermentation. The fermentation system used consisted of two packed bed reactors and a buffer tank between the reactors. An industrial wort and an industrial brewer's yeast strain were used. The wort was aerated by mixing air into the wort stream just before the inlet of the first reactor (pre-column). The air was diluted with carbon dioxide and both were filtered twice through a PTFE 0,2 μm membrane (domnick hunter Ltd., Durham, UK). The feed rates of synthetic air and carbon dioxide were changed independently according to a Box-Hunter experimental design while keeping the feed rate of the wort constant. The results were analyzed using a computer program for experimental design Modde 3.0, (Umetri AB, Uppsala, Sweden) and mathematical models for the concentrations of higher alcohols and two acetate esters in the out-flow from the pre-column were created. It was found that both low air feed and high air feed with low carbon dioxide feed stimulated the 3-methyl butyl acetate production in the pre-column. The main column seemed to even out the changes in the aroma compounds analyzed, so that their final levels were relatively insensitive to air supply in the range studied.

AB - Continuous immobilized primary fermentation has been studied since the last century, but has not yet fulfilled expectations. There are two main biological difficulties for continuous primary fermentation: achieving and maintaining the desired flavor and preventing contaminations. One traditional way of controlling the flavor of beer is by aeration of wort prior to pitching. We explored the effects of aeration in immobilized primary fermentation. The fermentation system used consisted of two packed bed reactors and a buffer tank between the reactors. An industrial wort and an industrial brewer's yeast strain were used. The wort was aerated by mixing air into the wort stream just before the inlet of the first reactor (pre-column). The air was diluted with carbon dioxide and both were filtered twice through a PTFE 0,2 μm membrane (domnick hunter Ltd., Durham, UK). The feed rates of synthetic air and carbon dioxide were changed independently according to a Box-Hunter experimental design while keeping the feed rate of the wort constant. The results were analyzed using a computer program for experimental design Modde 3.0, (Umetri AB, Uppsala, Sweden) and mathematical models for the concentrations of higher alcohols and two acetate esters in the out-flow from the pre-column were created. It was found that both low air feed and high air feed with low carbon dioxide feed stimulated the 3-methyl butyl acetate production in the pre-column. The main column seemed to even out the changes in the aroma compounds analyzed, so that their final levels were relatively insensitive to air supply in the range studied.

KW - flavor

M3 - Article

VL - 52

SP - 9

EP - 28

JO - BrewingScience

JF - BrewingScience

SN - 1866-5195

IS - 1

ER -