Beer changes during secondary fermentation

Beer changes 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,

• 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.

• 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.

• 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.

• 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.

Should we have cold room for beer fermentation or maturing?

Our standard configuration supply 2-3 times bigger glycol water tank than brewhouse. Some customers mentioned the local city water temperature is lower (about 23 degree). They can use enough city water to cool the wort firstly, then use cold room or small cooling system for wort cooling, fermentation or maturing, does it suitable?

Our idea is to keep standard configuration, you know the wort need to be cooled from over 100 celsius degree to about 10 celsius degree within 40 minutes, it is good for producing better quality beer. Also beer fermentation,it will need different fermentation temperature in different stage due to brewing different kinds of beer. But for the cold room, the temperature setted is same. Then all the fermenters will be cooled with same temperature.

If we have glycol unit, the temperature can set according to your demands. (There have temperature gauge on the control unit, each fermenter/bright tank will supply solenoid valve and temperature sensor). When the actual temperature is higher than setted, the solenoid valve will open and start cooling the temperature to setted. There have big flexibility than cold room cooling. Then it also will be better to cooling the bright tank for maturing with glycol unit.

Yes, also some brewmasters prefer to have cold room for the brewhouse. They will put bright tank in cold room and mainly use the bright tank as serving tanks, or they will use the cold room to cool the beer after filled. The temperature can stay same stage. If you also have the intention, it is OK to have one cold room.