When is it necessary to re-pitch yeast before bottling? I have two big beers fermenting now an imperial stout OG: 1.096 FG: 1.020 yeast is wlp 004 irish ale, and a barley wine OG: 1.099 FG: 1.018 yeast is safale US-05. The imperial stout shouldn't need more yeast it has only been in primary for 3 weeks and I'm probably going to bottle this weekend. I plan on letting it bottle condition for a long time. The barley wine however will be in primary for a month, and secondary for 2 months before I bottle it. Will I need to re-pitch for the barley wine? And if so whats the procedure for that? Oh and I should mention I don't have a keg so force carbing is not an option.
You probably will not need to repitch, but you might want to. Dry yeast is cheap. A 0.25-0.5 tsp or so, properly rehydrated, added before bottling might help. When I have lagered for a month or more, I have sometimes done this. Either way, the beers have always carbonated eventually, but boosting a populating may speed things up. Expect carbonation for these big beers to be slower than for a low gravity beer; you are asking the yeast to do something in a more hostile (higher alcohol) environment. My experience with big beers and carbonation includes Baltic porter, Braggot, and Imperial pils w/ OGs ~ 1.080, and several meads in the vicinity of 1.125. Except for the pils, these did not receive additional yeasts at bottling. I gave the pils ale yeast at bottling. Note that the meads that I carbonated were made with Champagne yeast, which has a high alcohol tolerance. If adding yeast at bottling time, this could be a good choice for this reason. However, I am not convinced that it is necessary.
Peter, the OPs two beers have OG’s of 1.096 and 1.099. Do you have an opinion on when it is necessary to pitch some dry yeast at bottling vs. just some ‘insurance’? For example, would you consider it necessary to pitch dry yeast if the OG > 1.090 but only ‘insurance’ if the OG is in the 80’s? Cheers!
Jack, I don't feel sufficiently confident in my own experiences to make a firm recommendation. If there is not a good treatment of this topic in Yeast, A Practical Guide, it might be worth sending a question to White Labs or Brew Strong. Off the cuff, my own thoughts are that you might want to repitch at bottling when (1) you used a highly floculant yeast (2) you used a yeast not known for alcohol tolerance (3) you aged your beer longer than usual. (4) never? Whenever I rack from primary to the bottling bucket, I intially stir up some yeast because the cane was too low. Maybe this little bit of yeast contains enough live cells to do the job?
#4 is why I'm not as worried about the imperial stout, I'm too lazy to hold the racking cane just off the yeast cake when transferring to the bottling bucket so I know some yeast gets sucked up. The barley wine is going into a secondary fermenter for 2 months so when I do bottle it there probably wont be much viable yeast left just hanging out at the bottom. If I do re-pitch should I stick with the same strain of yeast or should I get something like champagne yeast?
