High Gravity Imperial Stout

I did an imperial stout yesterday pitched the yeast at about midnight it's now 4:30pm no airlock activity. The gravity was about 1.090 I used what labs british ale yeast but did not use a starter. I usually do a starter but this batch was done on a whim and I did not want to put off this batch anylonger it's been months since I brewed. How long should I wait before pitching my back up yeast. I understand there can be some lag time with these heavy batches.

if all was sanitized well, i'd look for activity in three to four days...

you almost have to make a starter or pitch on a yeast cake if you are brewting that big mate!

One thing comes to mind. It can take a while. I direct pitched some WLP330 (Hefe) yeast straight in on a batch that I brewed on Saturday. I didn't get a Krausen until today. I have a blowoff tube and it was in my bedroom (don't ask ) , so I did hear a few 'glugs' during the night. So it can take some time. I wouldn't worry until you hit several days. As for the gravity, I think the problem really lies in finishing rather than starting at least that is what I have gathered. The highest I have gone to date is a 70 beer.

You know, I did an imperial stout last week with that very same yeast. Granted, mine was a mason jar full of fresh trub pulled from a conical at a local brewpub, but same yeast and all. I didn't do a starter, because it was freshly pulled from an active conical. And lagtime was LONG. Started VERY slow. Took awhile just to see a real krausen. Oddball. But I tried some last night. very good, but strong as a muf*ck. Went from like 1.095 to 1.030.

Anyway, if I were you, in the future, if you're doing one of those "last-minute" brews, try not to make it a high-grav one. They're the most brutal when it comes to needing a starter.

Yeah I just had to brew it's been way too long.

We just did an Impy Stout with an O.G. of 1.102 ... No starter, pitched a bottle of White Labs California Ale WLP001 ... tremendous airlock activity within 18 hours, its been going strong for 3 days now. I have used this yeast for several imperial applications and have dropped from 1.094 to 1.02 in as little as 6 days. Great versatile yeast IMO. But in regards to airlock activity hours after pitching, I never see that with a starter or not. Usually takes 12-24 hours. Make sure temps are above 70 at least until fermentation starts, unless youre lagering. Best of luck.