The beer changes happened during secondary fermentation
During secondary fermentation, some physical reaction, chemical reaction
and biological reaction are still going on slowly to improve the final flavor of beer. For example,
1.After primary fermentation, the beer temperature should be 3-5℃ in order that the fermentable sugars left (such as maltose and maltotriose)could be fermented further. Then, the CO2 produced would be dissolved into beer in a sealed tank to make the CO2 reach Saturated state. And, with the higher secondary fermentation temperature, the diacetyl could be reduced quickly.
2.The CO2 forming at the beginning of secondary fermentation would be blown off. At the same time, the bad taste and volatile substance could be discharged with CO2 together, which can facilitate beer maturation.
3.After 7-10 days, the beer is cooled to 0-1 ℃ gradually. The yeast, cold sludge and hope resin etc start to precipitate with lower temperature and PH to make beer clear and have a better mouthfeel.
4.With lower temperature, the protein which is easy to make beer muddy also start to separate out and precipitate. They would be removed during filtering. It is beneficial to improve non-biological stability of beer, then prolong the beer expiration date very well.
During secondary fermentation, the beer should be protected from touching air. Otherwise, the beer flavor, foam, color and non-biological stability would be affected deeply by oxidation, and is easy to be contaminated.
Edited by Vicky
Sales manager in Tiantai Beer Equipment Company
Email: tank@cnbrewery.com
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