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The performance of living yeast cells can be affected in many ways. Shipping and distribution can expose the yeast to temperatures which are harmful. Most of our products are shipped air freight, midweek to minimize transit time. Even with that we find some detrimental exposure on occasion. Loss of viable cells by age or temperature exposure are the most common beginnings of problems. If this is compounded by other factors, the performance can become unsatisfactory. A number of these are listed below.
Preparing a starter Culture Solution...
To make more beer, or increase the pitching rate, if the package is aged or not used right after it swells, boil a pint of wort S.G. 1.020 - 30 using 3 -4 tablespoons malt extract in 2 cups of water for 15 minutes. Cool to 75 F., add yeast and incubate for 12 hours or until high krausen.
Using the optimum timing and temperatures...
Delaying the use of the yeast after it starts incubating, whether from the package or a starter, can reduce performance. Make transfers in approximately 24 hr intervals at 75° F. Maintain at 75° F during incubation. Colder or warmer by a few degrees is significant. Longer or shorter time periods are significant.
High gravity worts...
(1.056 and greater need more yeast). Double the yeast amount for every 0.008 S.G. above 1.048.
Aeration...
is extremely important for all worts.
Dissolved oxygen ...
is required for the respiration of yeast at the onset of fermentation. One good method of providing dissolved oxygen for yeast is when preparing a starter solution, use a jar or flask with adequate headspace, then agitate the container frequently while brewing. By doing this, you will provide more dissolved oxygen to the yeast when it is most needed.
Uniform Temperatures are important...
keep at 75° F until fermentation is evident, and then adjust to the desired temperature. Fluctuations from night to day need to be minimized.
Wort Composition...
effects the amount of head thrown, and can vary among different yeast strains. Some ale and lager strains produce little or no head at first in some worts, although fermentation may be active, it may not be readily evident.
Barley malt is nearly a complete
nutrient source for yeast growth. The addition of some nitrogen,
vitamins, and trace elements is beneficial, but your yeast will survive
without it!
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