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In the actual production, sometimes we encounter this situation. After adding wort, the yeast starts to grow very slowly, even after 2 ~ 3 days, there is no sign of yeast. In view of this situation, we should first check whether the wort composition is normal, especially whether the content of a-amino nitrogen is low, and whether the temperature control and addition multiple are reasonable. At the same time, samples should be taken for microscopic examination. Under normal circumstances, the germination rate of yeast in the seed tank is 35% ~ 40% after adding 1 day, and the germination rate of yeast in the open propagation tank is 20% ~ 30%. The number of yeast cells in the added culture medium is not less than (6 ~ 8) × 106cfu / ml, and the mortality of yeast cells is not more than 1% under normal circumstances. It is necessary to check whether the culture medium is contaminated with miscellaneous bacteria. If it is contaminated, it should be discarded. The method is to raise the temperature of culture medium to above 80 ℃ for 60min, discharge after cooling, and thoroughly sterilize all pipelines and equipment. The expanded culture can be carried out again after reaching the sterile condition.
If no bacterial infection is found, the ventilation volume can be increased appropriately. If the infection does not start after 10-16 hours, a certain amount of culture medium in the previous stage of vigorous proliferation can be added. Generally, the infection can start after 12 hours. At the same time, the follow-up inspection should be continued.
Thank you very much for your reading.
Helen lee
Sales manager
[email protected]
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