1, fermentation liquid "billowing" phenomenon
Causes: mainly due to the improper opening of the cooling jacket, resulting in a large deviation between the upper temperature and the process curve, the middle temperature of the tank is higher, causing strong convection of the fermentation liquid. In addition, the pressure is unstable and the sharp rise and fall can also cause the fermentation liquid to churn.
Solution: check the meter is normal; Strict control of cooling temperature, to avoid the upper liquor temperature too high; Keep the pressure in the tank stable.
2, fermentation tank ice
When the lower temperature of the tank deviates from the process curve by about 2 °C, the temperature in the tank during the wine storage period reaches the freezing point of the beer(-2.3 °C--1.8 °C), which may cause the cooling zone to freeze.
Reasons for freezing: instrument failure, improper temperature parameter selection, improper thermal resistance installation depth, poor instrument accuracy, improper operation, etc..
Solution: check the measurement element and instrument error, especially to check whether the platinum resistance leakage, if the leakage should be baked after the paraffin seal or replacement; Select the proper temperature point position and the heat resistance insertion depth; Strengthening process management and timely discharge of yeast; The temperature of the cold medium should be controlled at -4 °C -2.5 °C, and the cold medium below -8 °C can not be used.
3, yeast self-soluble
Reason: When the temperature of the lower part of the tank differs from the middle and lower parts by 1.5 °C to 5 °C, it will cause difficulties in the settlement of yeast and the self-dissolution of yeast. Too high a temperature(16 °C -18 °C) and too long a time to maintain haicent.com can also cause yeast to self-dissolve, producing a yeast taste, and sometimes it can become turbid after beer sterilization.
Solution: check the meter is normal; Timely discharge of yeast sludge; The refrigerant temperature is maintained at -4 °C, and the upper, middle, and lower temperature of the wine storage period is maintained at -1 °C -1 °C.
4, drinking beer after the "above" phenomenon
Reason: General beer has a higher alcohol content of more than 120 mg/L, isobutanol exceeds 10 mg/L, and isoamyl alcohol content exceeds 50 mg/L, resulting in "upper" after drinking.
Solution: Select yeast species with low yield of high alcohol; To increase the addition of yeast appropriately and reduce the proliferation of yeast, the number of yeast cells should be 15 × 106 / ml; The alpha-amino nitrogen content controlled at 12 ° P wort is about 180 mg / L ± 200 mg / L; Control the dissolved oxygen content in wort juice at 8 mg/L -10 mg/L; Control fermentation temperature and tank pressure.