Causes of ice formation in fermentation tanks

During beer brewery brewing process, the fermenters inside may freeze sometimes, which will greatly influence the related links for beer brewing and beer quality. Then what is the possible reasons of fermentation tank inside freezing?

1. Unreasonable design of fermenter jacket

The cooling area of fermenter jacket is oversized, if with less fermentation liquid, the cooling speed is faster, without heat exchange in time, it will be freezed.

2. Improper temperature measurement points

In industrial brewery, for fermenter capacity over 10T, normally there are four temperature measurement points, which 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 period, we can select middle as temperature measurement points for safety.

3. Improper installation of the thermometer

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

4. Fermenter thermometer display error

The accuracy of the thermometer also is one of the reasons for the freezing of the fermentation tank. With poor accuracy, which is easy to result in big error.

With right temperature indicating, it can assure brew master timely adjust glycol flow or valve open level. If there have temperature error, tank temperature is high, but the beer temperature is lower, it is easy to freeze.

5. Improper operation

Improper operation is one of the main reasons for the freezing of fermentation liquid. The fermentation tank cooling is realized by glycol heat exchange. The glycol temperature normally at  -5 °C. After the main fermentation reduction is completed, if the cooling rate is too fast, the diacetyl reduction temperature is directly reduced to 0 °C , the poor convection will freeze the fermentation liquid close to the inner wall; or the cooling time is too long during the operation, the convection is not timely, which will also lead to freezing.

6. Unstable glycol temperature

The glycol temperature needs to keep stable, too high or too low is not good for fermentation control. If the temperature is high, it is difficult to finalize cooling process, if the temperature is lower, it is easy to result in freezing. -5℃ is better.

7. Yeast discharge is not timely

Timely yeast discharge is a critical step for temperature control. If settled yeast at tank bottom cannot be discharged in time, there will be a lot of yeast mud accumulated in the tank, and the thermometer inserted in the yeast mud. At this time, the thermometer shows yeast mud temperature, instead of the temperature of the beer, the blind cooling leads to freezing.

8. Instrument failure

In most breweries, it is normal to adopt platinum thermal resistance and stainless steel sleeve, during fermentation process, it has to go through clean, fermentation, filtration etc, the cleaning liquid temperature at 80 ℃-85 ℃, the fermentation temperature at 0 to -1 ℃, the sleeve is easy to form condensed water due to big temperature changes. The condensed water is not easy to discharge, the thermometer immersed inside for a long time, which is easy to cause the thermal resistance to fail.