little fermentation goin on

[J A]

It is odd that the directions of hydrating wine yeast state 100-104F, but then when you inoculate the juice, it is best to allow it to be cooler and closer to the temp of the juice.

Maybe there's just something about the material used to dry and preserve that particular type of yeast...Like a gelatin medium of some sort that needs a higher temp to dissolve completely to let the yeast cells get suspended. Maybe beer yeasts and most wine yeasts are preserved in material that doesn't need higher temps. Makes more sense that wine varieties shouldn't be that much more tolerant to higher fermentation temps...at least not triple digits.

 

[Nosybear]

We've never rehydrated our wine yeasts.... But given that aside, I think you're pretty much safe as long as the water is warm (above 85° F) but not too hot (below about 105° F).