In China, most breweries now use conical fermentation tanks for beer fermentation. The tank itself is equipped with a cooling device, which can easily control the fermentation temperature; the conical tank is easy to operate, saves labor, is easy to clean, and can also recover yeast. In order to save space, many large breweries install conical tanks in the open air; in craft beer, we generally do not use such large equipment and carry out it indoors.
The so-called “one-tank fermentation” means that the entire fermentation process is carried out in a conical tank, and there is no strict division between the pre-fermentation and post-fermentation, and the production time is shorter than the traditional process. Next, we will introduce the operation method in detail.
Commonly used lager fermentation process operation
The yeast inoculation temperature of lager fermentation is generally 6-10℃, the maximum fermentation temperature is 12℃, and the time from inoculation to canning is about 5-7 days. When the sugar content drops to 3.8-4.2℃, the can is sealed, the tank pressure is maintained at 0.12MPa after the pressure is increased, and the temperature is raised to 12℃, and the temperature is kept for 5-7 days to reduce diacetyl.
After that, the temperature is lowered to 5℃, kept warm for one day, and then lowered to 0℃. The cooling speed is different in different stages. The cooling speed in the 12℃-5℃ stage is 0.3℃/h, and the cooling speed in the 5℃-0℃ stage is 0.1℃/h. The post-ripening stage of lager fermentation is generally 5-7 days.
Common ALE fermentation process operation
The fermentation inoculation temperature of ALE is generally 16-18℃, which is higher than LAGER, and its maximum fermentation temperature can reach 20-23℃. It takes about 1-1.5 days from inoculation to canning, which is a short time. Similarly, when the sugar content drops to 3.8-4.2℃P, the can is sealed. After the pressure is increased, the tank pressure is maintained at 0.12-0.15MPa. After the temperature is raised to 20℃, the can is sealed. The timing is 5-6 days to reduce diacetyl.
The ALE fermentation cooling process is also cooled to 5℃, kept for one day, and then cooled to 0℃. The cooling rate in the 20℃-5℃ stage is 0.3℃/h, and the cooling rate in the 5℃-0℃ stage is 0.1℃/h. The beer is stored at a low temperature for 5-7 days to mature.
Key control points of the process
(1) Yeast addition
Dry yeast: 30-50g/100L for light beer and 20-80g/100L for lager.
(2) Temperature
Controlling different fermentation temperatures has its own advantages and disadvantages. When low-temperature fermentation is used, the yeast produces fewer by-products during the fermentation process, the beer tastes better, and the foam state is good, but the fermentation time is longer; when high-temperature fermentation is used, the yeast fermentation speed is faster, the fermentation time is shorter, and the equipment utilization rate is high, but more by-products are produced and the beer tastes worse. The general fermentation temperature of lager beer is 8-12℃, and that of light beer is 16-20℃. In addition, attention should be paid to the control of temperature in winter.
(3) Hygiene
Hygiene plays a vital role in the quality of beer. Care should be taken when sterilely inoculating yeast or dry hops. Hands should be disinfected when opening the well. The outer packaging around the well and the inoculated yeast should also be cleaned and disinfected. Use 75% alcohol as a disinfectant and spray it with a spray bottle. Pay attention to safety when disinfecting and do not use open flames.
(4) Fermentation pressure
The fermentation pressure of lager beer is generally controlled at 0.12MPa, and that of light beer is 0.15MPa. The fermentation pressure mainly depends on the final taste requirements of the product. The higher the pressure, the lower the temperature of the beer body, the more fully the carbon dioxide dissolves, the stronger the bactericidal power of the beer, and the richer and more lasting the foam.
Refequency questions
10 bbl Microbrewery fermenter
