Causes of beer freezing in fermentation tanks？

Causes of beer freezing in fermentation tanks？

The freezing point temperature at which beer or fermentation liquid freezes can be calculated by referring to the following formula:

T ice = - (alcohol content × 0.42 + wort concentration × 0.04 + 0.2)

For example, if the alcohol content of beer is generally between 3.2 and 4.2, the freezing point temperature is between -2.0 °C and -2.5 °C through calculation.

During the beer brewing process, the fermenter may freeze from time to time, which will greatly affect the beer brewing-related links and beer quality. Today, I will discuss with you the reasons for the freezing of fermentation tanks:

fermentation tanks

1. The jacket design is unreasonable↙↙

If the jacket area is too large, the cooling area is too large. If the fermentation liquid is too small, the cooling rate will be too fast, the convection will not be timely, and the phenomenon of freezing will occur.

2. Improper selection of temperature measurement points↙↙

Generally, there are four temperature measurement and control points at the top, middle, bottom and bottom of the conical fermenter. In the normal fermentation and cooling process, the upper temperature is lower than the lower temperature, which makes the convection in the fermenter strong. In the later stage of fermentation, the convection of the fermentation liquid in the tank is relatively weak. and become calmer. Therefore, during the fermentation, the temperature measurement parameters of the fermentation tank should be selected as the "intermediate temperature" as the temperature measurement point.

3. Improper installation of the thermometer↙↙

If the thermometer is inserted too shallowly, the measured temperature parameters can only represent a certain local temperature, and it is not easy to control; if the thermometer is inserted too deeply, it is easy to form a large temperature gradient and cause the fermentation liquid to freeze.

Brewery system brewing equipment

4. Thermometer display error↙↙

The accuracy of the thermometer is also one of the reasons for the freezing of the fermenter.

The accurate display of the thermometer ensures that the brewmaker can timely adjust the size and opening and closing of the refrigerant according to the accurate display of the thermometer. If the thermometer is deviated (for example, the temperature of the fermentation tank is high), the actual temperature of the beer liquid is too low, which will cause the fermentation liquid to freeze.

5. Improper operation↙↙

Improper operation is one of the main reasons for the freezing of fermentation broth in fermenters. The temperature of the fermentation tank is realized by the exchange of cold and heat of the refrigerant. The temperature of the refrigerant is generally between -8 °C and -4 °C. After the main fermentation reduction is completed, if the cooling rate is too fast, the temperature of the diacetyl reduction is directly reduced to 0 °C fermentation broth , the poor convection will freeze the wine liquid close to the tube wall; or if the cooling time is too long during the operation, the convection is not timely, which will also lead to freezing.

6. The temperature of the refrigerant is unstable↙↙

The temperature of the refrigerant needs to be kept stable. If the temperature of the refrigerant is too high or too low, it will have an adverse effect on the fermentation temperature control; if it is too high, it is difficult to cool down, and if it is too low, it will easily cause the beer to freeze. Therefore, the temperature of the refrigerant is best controlled at -6 to -4 °C.

food grade beer equipment

7. Yeast discharge is not timely↙↙

The timely discharge of yeast is a very critical step for temperature control. If the yeast that settles at the bottom of the tank cannot be discharged in time, there will be a lot of yeast mud accumulated in the tank, and the thermometer may be inserted in the yeast mud. At this time, the thermometer shows that the temperature is the temperature of the yeast mud. Instead of the temperature of the liquor, blind cooling leads to freezing.

8. Instrument failure↙↙

The temperature measuring resistance configured in the fermentation tank of most beer enterprises adopts platinum thermal resistance and stainless steel sleeve. Because the fermentation tank must go through the production links such as cleaning, wine feeding, fermentation, and wine filtering, the temperature of the washing liquid during cleaning is 80 ℃ - 85 ℃, the temperature of the fermentation broth during wine storage varies greatly from 0 to -1 ℃, and the platinum thermoelectric metal sleeve is easy to form condensed water when it encounters alternating cold and heat. Inserted at an angle of 45° downward, the condensed water is not easy to discharge, and the thermal resistance is immersed in the metal casing with condensed water for a long time, which is easy to cause the thermal resistance to fail.