Last weekend I brewed my first imperial stout. It came in at 1.091. I added one pack of WLP001 and 5 tsp yeast nutrient. I am concerned I didn’t add enough yeast. Is it too late to add a US004? Do I need to? Thank you.
If it’s fermenting already just leave it alone, should be fine. If it’s not fermenting definitely add yeast.
5 teaspoons of nutrient is an awful lot. I am not sure but that might affect yeast by adding too much. General rule of thumb is 1/2 teaspoon for 5 gallon batch.
It depends I guess. The Fermax I use calls for 1.0-1.5 teaspoons per gallon to optimize yeast activity or restart fermentation. …but that seemed like a lot so I use less.
If you are looking for a yeast strain that will definitely restart an imperial gravity beer, look at EC-1118. EC-1118 is technically a sparkling wine yeast, but it is neutral, alcohol tolerant, and does not need much in the way of FAN.
I agree that Lalvin EC-1118 would be a great choice as a failsafe if the fermentation stalls but if that’s not the case you can let it ride.
I don’t know what your fermentation temp is but one thing you can do with a big beer is raise the temp a bit and rouse the sediment a bit shortly after the krausen drops. Check the gravity then check again in about 3 days. If the gravity is unacceptably high and isn’t dropping then I would try the EC-1118.
Next time consider making a smaller beer first, 1.040 - 1.050ish. Plan on making your big beer on the day you package the smaller beer and just rack the big beer on the small beers yeast cake. Your small beer in essence becomes a 5 gallon starter.
Thank you for all the good feedback. I ended up not adding anything additional, and it looks like all is well. It’s currently at 1.029 on day 9.