Rehydrated yeast started bubbling/foaming

[The_Glue]

I rehydrated some yeast in boiled tap water and let it sit for like 30 minutes, it started "fermenting".
Is it a good thing or a bad thing?
I vaguely remember that it is not a good thing. (like they get used to the enviroment where they "woke" up so they will be less enthusiastic when they meet with more complex malt sugars or something like that.)

 

[slym2none]

It isn't fermenting, but showing signs of life. In baking, it's called "proofing your yeast", to make sure it's alive. You are proving your pack had healthy, usable yeast cells. Add a little sugar/DME and then you have something that's fermenting - although how you think that's bad, IDK. That's what you want when making beer!

 

[The_Glue]

It isn't fermenting, but showing signs of life. In baking, it's called "proofing your yeast", to make sure it's alive. You are proving your pack had healthy, usable yeast cells. Add a little sugar/DME and then you have something that's fermenting - although how you think that's bad, IDK. That's what you want when making beer!

That is good to hear, I thought they started eating the yeast food stuff that is get packaged with dry yeast.