Imperial Stout - Reusing Yeast

[TomDecapolis]

I just brewed an Oatmeal Stout that came in at 1.072 (got a little better efficiency out of my all grain system this go around so it ended up a little higher than I was expecting). I pitched two fresh Wyeast packs of 1056 (I would have done a starter if I knew I was gonna hit 1.072). The beer is fermenting away. This weekend I plan to brew a really big Imperial Stout, 1.100 +.

My question is this...when I brew the Imperial Stout this weekend the Oatmeal Stout should be ready to transfer over to a secondary (I plan to add some coffee to it). I have never reused yeast and was wondering if you guys think it would be a good idea to throw the imperial stout onto the 1056 that just spent a week fermenting the 1.072 Oatmeal Stout. Should I get another pack of 1.056 to be safe?

My original plan was to build up a really big 1056 starter this week...but I figured I would have this yeast cake sitting in the bottom of my fermentor and I might as well use it.

Any comments/suggestions would be greatly appreciated.

Thanks,
Tom

[Brandt]

What you are suggesting should be fine. But, I like to leave the beer on the yeast for the entire fermentation. It gives it time for the yeast to clean up all the by-products. So your oatmeal stout won't have that benefit if you move to a secondary. It should still be fine, but I like to be cautious.

You probably will have some tired yeast after the imperial stout which should be tossed out. I have had good luck with reusing a yeast cake, trub and all, for as many as 5 or 6 times with beers that are all medium gravity. But once you get in to high gravity, the viablility drops.

[NHBrewer]

Reusing yeast from a beer of that high of a gravity is not recommended. One thing that you
could do is take a small amount of yeast from the cake and use it to propogate a more healthy
pitch. The yeast from a 1070+ beer will be pretty pooped from all the work they had to do the first time.
By making a starter you build yeast in a nice easy environment for the yeast to grow and therefore end up with
very strong yeast which you will want for sure in a pitch headed for a huge Imperial stout.

Chris

[TomDecapolis]

Thanks for the feedback on the yeast. Any feedback on the recipe would be greatly appreciated as well. This is my first shot at an Imperial Stout. Trying to go for a Three Floyds Dark Lord clone and have had a hard time finding a good clone online.

Malt/Fermentables
14 lbs of Pale Malt (2 Row) American
3 lbs of Maris Otter Pale Malt
1.5 lbs of Roasted Barley
0.5 lb of Black Patent
1 lb of Chocolate Malt
1 lb of Crystal 120
.5 lb of Wheat Malt
1 lb of Flaked Oats

1 lb of Clover Honey
.5 lbs of Blackstrap Molasses

Hops
2 oz of Northern Brewer @ 60 minutes
1 oz of Centennial @ 15 minutes
1 oz of Centennial @ 5 minutes
1 oz of Cascade @ 1 minute

Extras
1 Vanilla Bean 14 days in Fermenter
3 oz of Coffee Beans 1 day in Fermenter – Crush by Hand

Yeast
Wyeast 1056 – Pitch on top of yeast cake that remains after fermenting 1.072 Oatmeal Stout.

Mash
90 Minutes at 152 Degrees F

Boil
90 Minutes

[Mylo]

Don't do it, man. Leave that first beer on the cake to clean up and make up a new starter for the Imperial Stout.


Mylo

[TomDecapolis]

Thanks for the feedback everyone! I decided to build up my own starter over the course of this week. Just left my LHBS and ended up changing my bittering hops to Columbus, figured 95 ibu's was more appropriate for what I'm going for. They also only had 1oz of centennial left so switched the one aroma oz to Amorillo.

[6thstreetbrewer]

I just did this for the first time (actaully did it twice.) I brewed a Mild (1.036) and pitched an IPA (1.072) onto the cake. I then brewed a Irish Red (1.046) and pitched a Russian Imperial Stout (1.091) onto the cake. The IPA fermented out fine with a FG of 1.015 but had a strange solventy flavor when I kegged it. It is still carbonating so haven't tasted the finished product yet, but was not thrilled upon initial tasting. It was fermented at 66 so I can't imagine that it was a temp issue. The Imperial Stout fermented at 64 and then ramped up to 68 after 1 week. When I checked the SG it was at 1.038 and pretty well stalled. It tasted good but 38 even for this big of a beer is just unacceptable. So after pitching onto a cake basically to save money I have come up with pretty shitty results and I'll probably stick to fresh yeast from now on.