Re-using Yeast

[CAlexander]

Hey guys,

I've been brewing for about 5 months now and I've got 8-10 batches under my belt, and I'll be moving onto all grain this summer. One thing I've never done (or fully understood) is re-using yeast. I hear it being done all the time, and I'm curious how it's done.

Can somebody fill me in here?

 

[FlyingHorse]

You could just pitch a new batch onto the yeast cake from your previous batch, or you could wash your yeast

 

[CAlexander]

You could just pitch a new batch onto the yeast cake from your previous batch, or you could wash your yeast

So immediately after I rack to a secondary I can pitch on top of what remains in the primary? Won't there be settled hops and such on the bottom as well?

 

[jjasghar]

You could just pitch a new batch onto the yeast cake from your previous batch, or you could wash your yeast

pitch with it?

litterally just dump it in?!?!?

it cant be that easy...and i'm assuming washing yeast is used for longer term storage?

 

[cheezydemon]

I highly recommend re-using the yeast immediately, I have not experimented with keeping it more than 3 weeks or so.
You should just think of the left over yeast as one hell of a great starter. I have pitched as many as six new batches in the same primary.
What is left in the bottom of your primary is not only yeast, but probably the most flavorful and concentrated half gallon or so of beer. If you do it this way, take the left over beer into account for the new recipe, and you will have to make an educated guess what this does to your OG as well. It should be a slight difference.
I always aerate thoroughly, don't siphon. OH! and taste your previous batch to make sure there is no obvious infection, I have never lost a batch, but if your primary is contaminated you certainly don't want to pitch a whole batch of fresh ingredients in! I believe that the extremely aggressive fermentation(keep a blowoff handy) and the fact that the yeast and leftover beer are alcohol laden makes this a pretty safe way to go. Good Luck!

 

[CAlexander]

I highly recommend re-using the yeast immediately, I have not experimented with keeping it more than 3 weeks or so.
You should just think of the left over yeast as one hell of a great starter. I have pitched as many as six new batches in the same primary.
What is left in the bottom of your primary is not only yeast, but probably the most flavorful and concentrated half gallon or so of beer. If you do it this way, take the left over beer into account for the new recipe, and you will have to make an educated guess what this does to your OG as well. It should be a slight difference.
I always aerate thoroughly, don't siphon. OH! and taste your previous batch to make sure there is no obvious infection, I have never lost a batch, but if your primary is contaminated you certainly don't want to pitch a whole batch of fresh ingredients in! I believe that the extremely aggressive fermentation(keep a blowoff handy) and the fact that the yeast and leftover beer are alcohol laden makes this a pretty safe way to go. Good Luck!

Wow, that's great. If I'm using, say, 6.6 pounds of LME, an ounce of bittering hops and an ounce of aroma hops, should I lower any of them to take into account the leftover beer?

 

[FlyingHorse]

Wow, that's great. If I'm using, say, 6.6 pounds of LME, an ounce of bittering hops and an ounce of aroma hops, should I lower any of them to take into account the leftover beer?

I never leave enough beer to make a difference in the new batch (<< 1 cup). Other than not pitching a "dellicate" beer on top of a more strongly flavored one, I wouldn't worry about it.

 

[CBBaron]

I've reused a yeast cake a couple times now. It couldn't be easier. In fact one of the reasons I have reused yeast is to save time.
I start my brew day as normal except my primary fermenter is full of beer that is ready to be transfered.
Once my wort is cooling down I transfer the beer in the primary to the secondary leaving the trub as normal.
Then when the wort in the kettle is cool I pour or siphon it on to the yeast cake from the previous batch.
Then you just need to stir the wort to mix in the yeast and aerate the wort.
You should have action in just a few hours.

WARNING - Using the yeast cake from a previous batch will most likely result in blow-off. Make sure you have a blowoff tube installed.

There is not much affect from the previous batch but it would be wise to avoid putting a lite tasting beer ontop of something strong. I wouldn't follow a Stout with a Blonde or an IPA with a Mild.
This technique is often used to get plenty of yeast for a really big beer like an RIS, IIPA or BW. In that case the previous beer is hardly going to matter.
Craig

 

[cheezydemon]

I am actually right now experimenting with leaving my dry hop bag from the previous batch in the primary with the new batch.
I have not noticed too much residual Hop flavor in subsequent batches, but then again I have been pitching stronger beers on top of weaker ones.
Taking this route is not quite as exact of a science as starting from scratch, but my optimistic belief is that you are more likely to stumble upon the greatest beer ever with a little uncertainty, than you are with exact adjustments and minute changes to an already tried and true recipe. Good luck! And my latest surprise discovery, is that you should not overlook Brown sugar just because it is a "cheap" adjunct. It actually has avery distinct and pleasant flavor enhancement in addition to being highly fermentable.

 

[Bernie Brewer]

Wash your yeast. Yeast is good for about four generations before it begins to mutate. When you make a batch of beer, that's one generation. When you dump onto a yeast cake, that's two, etc. When you wash your yeast, you can get four (or more) samples for each generation, thus getting much more bang for your buck. Plus, I've had washed yeast stay viable in the fridge for over a year. It's a bit more work, but well worth it.