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What is the foaming during bottle beer filling

Oct 20, 2018
helen

7998
Beer bottling

What is the foaming during bottle beer filling
During bottle beer filling, there is one procedure called foaming. What is the foaming? Why does beer need to foam?

1.The definition of foaming
After filling before capping, make the beer release CO2 to form fine and dense foam via knocking bottle, ejecting CO2 , using high pressure water or drop beer into bottle etc, then the foam would rise and overflow the bottle in order to exhaust the air in bottle-neck. After that, cap and seal the bottle quickly. This procedure is called foaming.

The most common way is spraying hot water into beer bottle by nozzles after filling before capping. The foam produced exhausts the air in bottle-neck, which would decrease the dissolved oxygen in beer efficiently. The high pressure hot water used to foam had better keep the following parameter.
Temperature: 85℃;
Hardness: 4°dH;
Pressure: 1000kpa.
Besides, the high pressure water should be filtered by membrane filter, then heated to above 80℃. It can not have bad smell.

2.The necessity of foaming
When the oxygen concentration in beer exceeds 2mg/L, it would have serious influence to beer stability. For 640ml bottles, the air amount in bottle-neck is around 30ml, which equals to around 13.125mg/L oxygen concentration. It will do harm to beer flavor greatly. Therefore, it is necessary to exhaust the air in bottle-neck. The solution is foaming during beer filling. A good foaming can reduce the air amount to 1.5ml even less. In this case, the oxygen concentration will become lower than 0.5mg/L. Foaming takes a far great significance to beer stability and service-time.

After foaming, the capping time should be controlled during foam overflowing, rather than before or after overflowing. Before foam overflowing, there are still much air in bottle-neck. After foam overflowing, there is also much air in bottle-neck with foam disappearing. So, the capping time should be controlled during foam overflowing.

Edited by Vicky
Sales manager in Tiantai Beer Equipment Company
Email: tank@cnbrewery.com

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