Principles of saccharomycetes expanded culture.There are 5 main principles in total for how to expand yeast. Let’s go to the fist part.
The key to expanding yeast culture is the use of excellent single-celled bacteria. The bacteria should pass an assessment of physiological properties and performance before they can be used. It is also necessary to ensure that the culture is free of contamination and mutation. All residual fluids from the culture should be checked for contamination and mutation free.
During the culture phase, the optimal temperature is about 25°C in order to increase the emergence rate and shorten the emergence time. After each expansion, the temperature will be lower than before, to make the yeast adopt the requirement of low temperature fermentation. However, the rate of temperature reduction should not be too great so that the activity of saccharomycetes will not be inhibited.
In order to shorten the saccharomycetes growth stagnation and culture time, we prefer to transplant the saccharomycetes at the double growth stage in all stages of the expanded yeast culture. Especially transplanting saccharomycetes before the saccharomycetes growth rate becomes slower. This is when saccharomycetes growth rate is high, mortality rate is low and growth rate is fast after transplantation.
Once the yeast is transplanted to the production site, we need to pay attention to the ventilation support and moderate ventilation after adding 8-10mg/L of wort.
Usually cooled wort is used at the production site. Cooled wort is easily contaminated when passing through pipes, especially when transported over long distances.
Nutrients and multiplication of expanded cultivation.
This requires the use of a rich medium for yeast cultivation.