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FreeMountainHermit wrote:Another quick question is why there seems to be a disparity in the amount of yeast pitched in some of the recipes I've read here when the volumes of the mashes are the same.
Thank you, FMH.
It is very important to re-hydrate the yeast properly. In the initial microseconds of re-hydration yeast cannot control what enters their cell walls so it is important to use only sterile water or sterile water and a product like Go Ferm Protect, which is designed for yeast re-hydration. Re-hydrating with wort can result in the immediate death of up to half the cells in the colony which results in a longer lag phase and longer fermentations. Also re-hydration time should be limited to 15-25 minutes, that is, only enough time for the water to be absorbed and the yeast colony to become a nice smooth slurry. Don't stir for at least the first 10 minutes. Water temps should be 85-105 F depending on the specific yeast. Also, water quantity should be 10-15ml/gm of yeast.
rad14701 wrote:Pitching a larger volume of yeast, whether dry-pitched or as as a starter solution, reduces initial lag time but can also cause off tastes and smells... Finding what works best for each individual type of wash is what's most important... For example. turbo yeast packets contain a lot of yeast and a lot of supporting nutrients... For other yeasts the most common volume is 5 grams per packet, which should be enough for a 5 - 6 gallon (20 - 25 liters) of wash but may result in 12 - 48 hours of lag time... Increasing the amount of yeast pitched, to an extent, simply reduces the amount of lag time required for the yeast colony to reach a density that will cause them to switch from the aerobic to the anaerobic phase, whether oxygen is still present or not... If a too small of an amount of yeast is pitched and all oxygen is depleted the yeast will switch to anaerobic mode whether the colony has reach its pre-programmed density or not and the fermentation will simply take longer to complete... They will slog along either until the fermentation is complete or all nutrients have been consumed and they revert to autolysis (cannibalism) and the colony dies...
This is very true... luckily all-grain worts/washes have a much higher and diverse nutrient load than must. Also, your starter yeast population can only grow in proportion to the size of the starter itself. So if you make the initial starter the right size then that is not a problem.Pop Skull wrote:If you do use a starter if the yeast population gets too high, you can have this yeast population exhausting the nutrients in the must. When nutrients aren't available for yeast, they tend to make byproducts that you defnitely would think twice about drinking in a wine. Sulphides, acetic acid and such as well as other off flavors.
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