Reusing Yeast?

The next two brews I do will both be using the same yeast (White Labs Burton Ale), and I was hoping to make a starter from some of the liquid/trub that remains after racking the first batch, which would then be pitched into the fresh wort of the second batch the following day or so.

How do you go about transferring the trub/yeast? Is it as simple as scooping some out and funneling it into a prepared starter flask?

Search "yeast washing"....or is it "washing yeast". It will teach you all you need to know.

Actually - its almost that simple. Short answer is to boil some water and cool it to around 70 deg. Pour that into your trub and swirl and pour into another vessel to sit and let separate overnight or longer. Once it separates, pour off the liquid on top, keep the creamy off white stuff in the middle and get rid of the crap at the bottom.

When you're ready, make a starter and pitch the slurry into it just like a smack-pack or vial of White Labs.

Take a look a the Yeast Washing thread in the general techniques forum.

Gordie.

Check out the FAQ section on Danstar's website.

Or you can just pour the wort for your second beer onto the yeast cake left after racking your first out of the primary. You don't need to make a starter for the second with the amount of yeast you'll have there. Just make sure your first beer is lighter than your second.

JayC hit it right on, a simple one time - reuse is fine just pouring on the yeast cake. At least it has worked for me everytime.

This post should help guide you. Pitching slurry is done all the time, and is easy as scooping up some cake from the fermenter. I do not and have never recommended knocking out onto a cake. Read the link for why.

Cheers,

Bob

I just brewed two back-to-back versions of a holiday ale and wanted to re-use the great white labs yeast from the first batch as it did so well. All I did was siphon out the beer from the primary into the bottles as normal, leaving the trub and a small amount of beer behind. I swirled the remaining trub/beer real good in the carboy, then removed the filtering tip from my racking cane and stuck it all the way down into the trub. I siphoned off some trub into a sterilized 16 oz. flip top bottle and sealed (as I was re-using the same day). When the new wort was ready, I just poured that 16 oz. right into the new wort. I will probably re-use yeast again like this - but you need more than the 16 oz. I used if you primary your beer for 3 weeks or more as it took about 26 hours or so for active fermintation to start. I will shoot for 22 oz. next time and see if it works better.

A starter is obviously better, but I did not want to mess with it or yeast washing and re-pitching the trub worked just fine if the beer style and OG's are relatively the same.

DD2000GT said:

I just brewed two back-to-back versions of a holiday ale and wanted to re-use the great white labs yeast from the first batch as it did so well. All I did was siphon out the beer from the primary into the bottles as normal, leaving the trub and a small amount of beer behind. I swirled the remaining trub/beer real good in the carboy, then removed the filtering tip from my racking cane and stuck it all the way down into the trub. I siphoned off some trub into a sterilized 16 oz. flip top bottle and sealed (as I was re-using the same day). When the new wort was ready, I just poured that 16 oz. right into the new wort. I will probably re-use yeast again like this - but you need more than the 16 oz. I used if you primary your beer for 3 weeks or more as it took about 26 hours or so for active fermintation to start. I will shoot for 22 oz. next time and see if it works better.

A starter is obviously better, but I did not want to mess with it or yeast washing and re-pitching the trub worked just fine if the beer style and OG's are relatively the same.

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How many times can you repitch on a previous yeast cake? Don't the yeast start to mutate after a while?

If you're careful, dozens of generations. You must pitch the proper amount, control temperature, sanitize religiously and wash the yeast every so often, you should be all right. Now, you'll have to brew regularly, mind, in order to have the freshest possible slurry.

You can knock out onto a yeast cake - i.e., just going from kettle to just-emptied fermenter - once. Some brewers have reported success in subsequent batches, but I can't bring myself to trust that testimony. Yeast will start to mutate with repitching, even if you harvest and repitch properly, and those mutations are never desirable. Proper harvesting and repitching minimize the mutation, stretching it over many more batches, but it still happens.

Cheers,

Bob

EDIT: Got the answer I was looking for from one of Bob's posts, in another thread.

Cheers mate-ies.

i did that once .... after i finished bottling my beer i still had a lot of yeast / trub on the bottom ... so i sipnoned it out into another bottle, capped it, stuck it in the fridge at 35 degree's

i was able to use it a month later with zero problems

What about using (re-using) the yeast from the secondary?

Thanks in advance

Steve

n2dsky said:

What about using (re-using) the yeast from the secondary?

Thanks in advance

Steve

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I did this with my last batch. The plus side is that it had much less trub. The minus is that I din't really get enough to pitch directly without using starter. I'm talking about washing and storing, not direct pitching of new batch onto the yeast.

I guess that's what I'm checking on.

I've got a fairly thick layer (about 3/4 inch thick) in the bottom of the carboy after 7 days.

Transfered fairly clean from the primary after 5 days (due to a bunch of hops and trub being put in from the boil pot)

I'm going to bottle in the next couple of days and was thinking I'd just save all the cake at the bottom of the carboy for the next batch.

Thanks for the input

Steve

If you repeatedly reuse the yeast from the secondary, you'll be preferentially selecting for the less flocculant yeast, and it'll take forever to clear. Doing it once or twice shouldn't hurt, though.

so, right after I bottle my beer.....I can just pour a new batch of wort onto the yeast cake stuff at the bottom of my carboy, put on the airlock, and let it go to work again? Even if a tiny tiny bit of beer didn't make it out the carboy?

Simple as that?

Check out Bob's post here for why that's not a good idea. He's the third one down on the second page, post 13. I'm just going to follow his advice, take a sample from the yeast cake, and use it to start a starter.

Pelikan said:

Check out Bob's post here for why that's not a good idea. He's the third one down on the second page, post 13. I'm just going to follow his advice, take a sample from the yeast cake, and use it to start a starter.

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hmmm....ok, so it's considered overpitching.

Here's a question then, could one maybe scrape out a portion of the cake and then pour the wort on top of what's left?

ApolloSpeed said:

hmmm....ok, so it's considered overpitching.

Here's a question then, could one maybe scrape out a portion of the cake and then pour the wort on top of what's left?

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One could really do whatever they want. But why cut corners with something you're investing at least $20 and four weeks of your life into?

Based upon what Bob said, and in my opinion, taking a small scoop of the cake to start a starter is the safest and best bet.

Followup: I followed Bob's sage advice. After racking my brew into the bottling bucket, there was a very healthy-looking cake remaining. Without being too selective, I scooped up slightly more than one tablespoon of cake (with a sterilized instrument, of course) and blopped it into a prepared starter.

Twelve hours went by, and there was pretty much no activity. I was about to give up on it, but at right around 18 hours it really started to come to life. The pic below was taken at about hour 18, when tons of small bubbles were rising through the wort (barely visible in the photo), forming a notable krausen (very visible in the photo). The krausen has gotten about twice as large since then. The airlock started constant bubbling at about the time of the photo, which has remained steady to this point (about 5 hours later, and ~24 hours from pitching).



I'm going to wait until activity tapers off considerably before I pitch (so, either tomorrow or Friday). By all accounts, this looks to have been a success, and really couldn't have been easier. Yeast washing is all well and good, but I really don't see the dramatic benefit to it, given that it will only stay good in the fridge for a limited amount of time. Rather than deal with all those steps, each one a vector for contamination, it's so much easier to make a starter and pitch that. Repeat as necessary, up to five generations.

For those interested in the exact steps take: I prepared a starter solution with four ounces (weight) of DME, 1/4 tsp Wyeast Nutrient, and about 1 liter of water. Boiled for about 10 minutes, and immediately added the wort to a sterilized flask, and topped off to 1 liters with spring water from a newly opened bottle (while the wort was still boiling hot). Place a tin foil square over the opening to the flask, and cooled in an ice bath for about 30-45 minutes, until flask was cool to the touch. Transferred ~1 tablespoon of unfiltered/unwashed yeast cake to the flask, then immediately put a sterilized, drilled rubber stopper in place, complete with sterilized airlock.

...and now it's doing its thing. I'll have to post another update after I try the finished brew.

I just poured my new wort onto the yeast cake in the fermenter, and it worked great. Tasted nearly the exact same as the orginal batch. WLP400 yeast.

I'm not sure about doing it more than twice, but twice did worked for me.

BobNQ3X said:

You can knock out onto a yeast cake - i.e., just going from kettle to just-emptied fermenter - once. Some brewers have reported success in subsequent batches, but I can't bring myself to trust that testimony. Yeast will start to mutate with repitching, even if you harvest and repitch properly, and those mutations are never desirable. Proper harvesting and repitching minimize the mutation, stretching it over many more batches, but it still happens.

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First off, I'm not a biologist, and I can't say I'm an expert in genetic mutations. That said, I don't understand why yeast will mutate more in one scenario and not the other. What does washing do that minimizes mutation?

Anyway, I'm planning on pitching a 1.086 Doppelbock onto the cake from a 1.046 Munich Helles, which my understanding is the correct amount of yeast for a lager of that gravity, according to Mr Malty.
So, like most things in brewing, there are always exceptions

gxm said:

First off, I'm not a biologist, and I can't say I'm an expert in genetic mutations. That said, I don't understand why yeast will mutate more in one scenario and not the other. What does washing do that minimizes mutation?

Anyway, I'm planning on pitching a 1.086 Doppelbock onto the cake from a 1.046 Munich Helles, which my understanding is the correct amount of yeast for a lager of that gravity, according to Mr Malty.
So, like most things in brewing, there are always exceptions

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With washing, you're preserving a bunch of yeast from the end of that first generation. So no matter how many times you cracked a jar from that washed batch, it would still be second-gen yeast. But if you keep repitching and repitching and repitching, eventually natural and artificial selection will leave you with something that's not entirely like what you started with. How dramatic that difference becomes is not something I'm qualified to comment on, but a number of professional yeast companies recommend a max of five generations, after which differences will become apparent.

With the average, highly flocculating brew, you gotta figure there's about a pint of yeast cake down there, perhaps even double or triple that under ideal circumstances. So one is dealing with about 700-800 billion yeasties in an average fresh cake, maybe more. Whether that's overpitching in your case or not, I couldn't say, but something about direct pitching onto the cake irks be a bit, as in something in my subconscious tells me it just shouldn't be done, especially not more than once.

gxm said:

First off, I'm not a biologist, and I can't say I'm an expert in genetic mutations. That said, I don't understand why yeast will mutate more in one scenario and not the other. What does washing do that minimizes mutation?

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I don't mention washing. I speak only about harvesting slurry. That clarified, harvesting and pitching inoculates the fresh wort with what I consider the proper amount of active cells to encourage a healthy ferment. As I've written elsewhere, the brewery standard for pitching is 1 million active cells per milliliter of wort per degree Plato. This is for inoculation, not fermentation. During the aerobic phase of the yeast's life cycle, the inoculated cells metabolize oxygen and other materials in order to make copies of themselves. They stay in the aerobic phase until either the solution reaches saturation or they run out of a necessary component of replication, whereupon they switch metabolic paths to anaerobic. That's when they start eating the malt sugars and putting off carbon dioxide gas and ethanol.

The trouble with overpitching - especially at the rate of knocking out onto a cake - is that the colony never enters the aerobic phase. They immediately and voraciously start devouring wort sugars. When I wrote of mutation before, I should have written about the complete lack of mutation, because the colony never replicates after the first pitch. They never refresh themselves. They get tired. This puts the cells under stress. It can also create off-flavors, not least of which is a lack of any sort of yeast-ester flavor contribution, which only really happens in the aerobic phase. Moreover, the presence of excessive yeast during the ferment can lead to meaty, rather foul off-flavors.

At any rate, the colony will suffer condemnation from the brewer after far fewer pitches - I used the term 'generations' erroneously - for off-flavors and poor performance, compared to careful harvesting and repitching. Harvesting does set up mutation, because the colony is replenishing itself during every aerobic phase. However, careful harvesting, along with washing and other yeast-management techniques, minimizes the impact of natural selection, by removing trub as well as dead, weak and/or powdery cells.

The evidence is clear - brewers have, do and can harvest and repitch hundreds of generations of the same yeast strain. On the other hand, even the staunchest proponents of knocking out onto cakes will only do it less than five times.

Anyway, I'm planning on pitching a 1.086 Doppelbock onto the cake from a 1.046 Munich Helles, which my understanding is the correct amount of yeast for a lager of that gravity, according to Mr Malty.
So, like most things in brewing, there are always exceptions

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~300 milliliters of slurry. That's all you need to properly inoculate 5 gallons of 1.086 lager. Is your Helles yeast cake really that small? That's less than a third of a liter.

I don't think this is an exception; I think there was an error somewhere.

Respectfully,

Bob

Thanks for all the additional information Bob. I hadn't realized that many of the ester flavors are created during the aerobic phase, and I hadn't thought about the consequences of not allowing the yeast to reproduce when pitching onto a yeast cake.

As for the size of the yeast cake, I'll have to measure it when I rack off the Helles.

BobNQ3X said:

~300 milliliters of slurry. That's all you need to properly inoculate 5 gallons of 1.086 lager. Is your Helles yeast cake really that small? That's less than a third of a liter.

I don't think this is an exception; I think there was an error somewhere.

Respectfully,

Bob

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I harvested about 500 ml of slurry from the yeast cake. Since the Helles ended active fermentation on 11/6, I used that date to calculate viability. Mr Malty recommends 400 ml of slurry, and 500 seems well within the margin of error. After 12 hours, the fermentation is proceeding at the same pace as the original Helles fermentation which had a 1 gallon starter, so it seems pretty good to me.