15 janvier 2015 Bruno


Improvement of resistance against beer staling

Last scientific researches confirm that the staling-potential of a beer is essentially determined in the brewhouse. Therefore it is very important to act as soon as possible in the brewing process.

First of all by trying to minimize oxygen presence (flours, brewing water, brewing under CO2, etc) and by decreasing malt lipoxygenase action during brewing (unsaturated lipids oxydation to lipid peroxides that can oxidize proteins and that can act during wort boiling as precursors of compounds like trans-2-nonenal).
After that care has to be taken during wort boiling to minimize oxidation processes and especially lipids oxidation (peroxides lipids). Oxidation reaction products like trans-2-nonenal (cardboard taste) can in the first place establish bounds with compounds like sulfites for example that make them imperceptible in just bottled beer. Later, these sulfites become gradually oxidized in the beer bottle releasing the undesirable compounds that become perceptible at this moment.

The use of an antioxidant and natural reducing agent at mashing-in (Tannox-Brew) allows to decrease malt lipoxygenase action (more than 50%). In fact lipoxygenase needs its core to be at ferric state (Fe3+) as well as molecular oxygen presence to oxidize lipids into peroxides. Ferric core reduction into ferrous iron deactivates this enzyme. The decrease of oxygen disponibility slackens lipoxygenase action. TANNOX-BREW antioxidant action also decreases proteins oxidation and therefore increases wort filtration rate. The use of classical antioxidants like ascorbic acid-sulfites couple during wort boiling completes this first anti-staling action in the brewhouse.


During wort boiling hop is added to perform isomerisation step. Hop also can then be oxidized giving rise to several compounds that can significantly participate to typical tastes and flavours faults of stale beers. Separated isomerisation of a very concentrated hop extract solution (a minimum of 20% of alpha acids in solution) allows to minimize hop oxidation thanks to natural hop reducing power. This reducing power is significant when isomerisation is performed on a concentrated hop extract solution but it is not sufficient at usual concentration in wort. Substitution of a part of classical hopping by a product like Isototal isomerized at high concentration can also contribute significantly to improve beer anti-staling resitance.

Fight against oxygen presence in beer has to be continued by classical ways during bottling and by adding an antioxidant to finished beer.



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