IPA on lager yeast cake

[Cain Harland]

I have Schwarzbier brewing (fast lager method) and it seems a shame to waste the yeast cake. Usually I brew IPAs and don't re pitch because between the kettle trub that makes it into the fermenter and the dry hop there is a lot of crap in there that I don't really want going into the next brew and washing it seems like too much work. But with no dry and relatively few kettle hops this one should be pretty clean and with a relatively low ABV should be fairly healthy. Next brew will be an IPA (as usual) with an OG in the late 1.06s or very early 1.07s so 2 questions.

1) is it a bad idea to try and brew a hoppy IPA on a Schwarzbier yeast cake and if so why

2) how much trub to re pitch into 40l of wort

I actually tried this before and got what was a very sessionable beer but slow to take off (pitching rate or is just the way with lager yeast?) and a little under whelming on the hops (not blaming the yeast but I'm interested on others opinions on lager yeast in hoppy beers). The only reasons I can see to use a clean ale yeast over lager are speed and pitching rate (both of which aren't relay problems when you have a yeast cake and ascending fermentation temprature) but I might be overlooking something.

[Crusader-Rob]

I'd still recommend washing the yeast, due to the darker colour. give it a couple of rinses, and it'll be good to go.

[Des Ross]

In my opinion the simple plan is the best....washing yeast just opens the opportunity of infection and in my experience, even using the complete yeast slurry from a hoppy IPA or stout style to dump onto, the colour and hop residue will not have a noticeable influence on the next beer. A large proportion of the trub will actually be metabolised by the regenerating yeast. I say brew on the same day you keg and dump the wort straight onto the yeast slurry. Then you can make your own assessment on whether colour or flavour from the slurry carries through to the next beer. I reckon it doesn't.
My only caution would be to make sure the temperature of the introduced wort is not too high ( I would suggest 17-18C to start ) as there will be a lot of heat generated by the huge yeast population.
I think you are spot on in your assessment so try it for yourself.... I learned many years ago that most of my best bers were the result of experimentation

[jt]

If you really want to brew with the yeast, if you think it'll suit the beer, then go ahead.

Just work out how much you need with the mr malty calculator, don't dump it onto a whole yeast cake, that's a wild over pitch
If you have good enough sanitation it won't be a problem. (If you don't then you probably shouldn't be brewing?
I think joking did a good blog post about saving/repitching slurry a few years ago, worth reading

[Des Ross]

Yes certainly a big over pitch but I don't think it would compromise the beer in this particular situation. There is a lot of information on the internet relating to practices around under pitching / over pitching....here is one sample

http://www.homebrewtalk.com/showthread.php?t=166221

In Cain's situation he would be pitching a 40L high gravity IPA onto a 1st generation lager yeast cake, an over-pitch but as long as there is good temperature control I still think his idea is sound and he will get good attenuation. If it was a low to medium abv beer being pitched onto a 2nd- 3rd generation ( or more ) slurry or no accurate temperature control of fermentation, then good brewing practice means being a lot more precise and careful with re-used yeast.

[Cain Harland]

Being a lager yeast and pitching temp being like 9c re pitching onto the whole cake is probably not really an option any way as I need to put the fermenter in the fridge to finish chilling so the yeast needs to go in a jar overnight.

[Cain Harland]

Another repitch question for you knowledgeable folks. Say I've brewed a small beer, 2 weeks primary and 1 week cold crash and collect a couple of jars of slurry. I will pitch the first one immediately, how long is the other one good for, if I want to pitch it straight into a brew?

How often does viability half for yeast stored under beer in a fridge?

Is it worth saving the second one at all if I'm not planning on making a starter from it?

[Cain Harland]

Using Mr Malty I can work out that yeas viability halfs about very 4 weeks so next question. At 4 weeks is it safe to just pitch twice as much slurry? Will all the dead yeast produce off flavors or provide nutrients for the live ones.

[Peter Smith]

After 4 weeks I normally make  a 2.5L starter with the 4 week old yeast,