re using yeast cake

so i just made a white IPA this past saturday and i think i'd like to do another batch this saturday. maybe next wed. either way i was curious about reusing the yeast cake from the first batch.
do i have to put the new wort on top of the old cake or can i dump the cake into a new fermenting bucket?
saving the $8 would be nice, but i'm more curious about how well this works and like the idea of being more efficient without getting into washing the yeast which just seems like too much for me. (i dont currently make starters)
im sure this has been answered but didnt stumble on it and was lkooking for a more direct answer. from what ive read if the cirst batch off the cake seems fine, i should be good to go, right?

 

I do this ALL the time for my ipa. I seem to be able to make about 3 batches on the same yeast before I see any problems with stuck gravity. The second batch always performs the best. Absolutely no problem with this in my book

 

and do you just rack the wort onto the old cake in the original bucket/carboy or do you transfer the whole cake into a new bucket/carboy?

 

depending on the gravity of the new beer i use 1/4 to 1/2 cup of slurry right into the fresh wort. the rest of the yeast cake i might jar up and save for later or just dump it and use part of the new cake on the next beer and so on. while dumping the wort right onto the whole yeast cake will produce a beer, it won't be the best beer you could make.

 

Read the yeast washing sticky it's super easy then you get a few batches out of one yeast cake

 

I do this all the time but never use the full cake. If you read about slurry repitching you will see that using the full cake will way over-pitch. depending on the yeast strain this may not be a big deal. In any case it is just as easy to scoop out a 1/2 cup of yeast cake and drop it into your next batch. Higher gravity brews get maybe 3/4 to 1 cup. Check Mr. Malty for slurry pitching rates to get an idea. If you decide to pitch on a full cake make sure you have a blow-off tube attached!! If you just want to make beer then do what you want. If you want to make great beer then I would advise on adhering to pitching rates as much as possible.

 

here you go

http://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/
http://www.homebrewtalk.com/f39/pitching-yeast-cake-257296/

 

+1

At the end of fermentation the amount of yeast left is about 6 times the amount recommended for proper initial pitching. Some will have died, so I generally use about a quarter of the cake for the next beer of similar gravity. If the OG of the new beer is 2X the old one, I would use half the cake.

Pitching on the whole cake will make a decent beer, but it is over-pitching which will result in less new yeast cells being reproduced, and the old 'stressed' cells having to do most of the work in the new beer. The effects may be unnoticeable, but the new beer will have less yeast derived flavors, could end up a couple of points higher, and may develop more fusel alcohols.

 

I've pitched the whole yeast cake a few of times and never noticed any off flavours. They are probably quite subtle but still there.
It's probably better not to use the whole yeast cake.
It's a very good process to do when making lager, first make 2-3 gallons of lager using one activator and then use the yeast cake to make a 5-8g batch.

When the yeast cake is from an IPA I would definitely wash the yeast first. Depending on the recipe of course but you would probably have rests of hops in the yeast cake that you wouldn't want in your new beer.

 

very helpful post, thank you. i have yet to really start reading up on yeast science or water chemistry etc. i've just gotten into brewing. started and have stayed all grain and have done about a dozen brews. i want to make another batch of this white IPA and then create my own IPA. then do something totaly different.

i was talking about making the exact same batch.

and i will read those other links posted as well. thanks, guys.
btw, just scoop out a 1/4 cake with anything sanitized and just dump into the new aearated wort?

 

wow, thats a ton of info in those two threads

 

I have simply collected the cake from a finished batch and divided it into two sterilized jars. Then, presto, I have two batches ready for a starter when I'm ready to brew that recipe again. It's worked ok for me so far. I usually only re-use twice though. That still gives me a potential of 7 batches from 1 yeast packet though. (I guess I haven't ever actually done ALL 7 batches, but the possibility is there.)

 

yeah, i'd be happy just halving the cost of yeast per batch!