Heathens, the lot of you!
To convert sugars into alcohol, yeast is needed. Different strains have different tolerances (amount of alcohol that can be produced before they die) with wine yeast in the higher range than beer. Natural yeasts are present in most fruit as well, thus why some wine could be made without the addition of yeast (though NOT recommended) Beer yeast is traditionally sold as a liquid- yeast cells mixed with a food source that will keep until they are pitched into wort (beer) and can begin eating the sugar and multiplying. You can also buy dry packets, but those must be rehydrated before adding to beer. Once they have finished with all the sugar, or reach their peak tolerance in alcohol, the yeast dies. This is no longer of any use to a brewer, and is considered "spent yeast." This will always be in a liquid, or slurry form, as it is the trub from the bottom of the beer. (Stuff that falls out, leaving the beer to be pulled off and bottled / kegged).
As far as how to dry, I would assume any method used to get the water content out before mold etc could set in would work. I usually just toss my spent yeast, but have poured it into a simple container and left in sun before, and after it dried, the bees did take to it.
If you look at the yeast, it should be pretty fine to begin with... shouldn't have to grind I wouldn't think...
Not sure if that helps clarify, or muddies the waters.
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