How long are you willing to wait for signs of fermentation?

[Boerderij_Kabouter]

To answer the OP, I am pretty upset about things If I am not bubbling away within 12-16 hours. If a ferment takes 72 hours to start actively fermenting, the reproductive phase was WAY too long IMO. Properly prepared and utilized yeast will provide a rather consistent ferment with predictable results.

I haven't dumped and prayed in a long time. That said, if I didn't have an active ferment right away, unless you had a backup starter going, it isn't worth pitching extra before that 72 ish hour range.

Also, you will get an infection regardless of how good your sanitation processes are if you wait long enough. There are a few good studies and tests you can run to see how good your sanitation practices are based on how long it takes for infections to take hold. The question is not if you will get an infection, it is when.

 

[remilard]

If you own a pH meter, you can tell if your yeast are active within a couple of hours of pitching (the pH will drop).

I'd hate for someone to sit around for 72 hours while their $60 pH probe that they use once a month is getting 72 hours closer to needing to be replaced.

 

[SkiSoloII]

I didn't wait long enough....... Pitched a small jar of slurry (Wyeast 1275) from a brew I racked on 3/7. Pitched into a Porter I made Sunday. Didn't seem to start after 26 hours. Sprinkled in 2 pkgs of Notty...... BOOM!!!!!!

Damn..... Lost a lot of beer to blowoff. I think it's still blowing off.....

Dave