# Storing & Re-using Yeast Slurry



## hughman666 (6/6/07)

Hi all,

I realise that various sections of this topic have been covered in various different topics. However, many of them are 5+ pages long and sometimes containing conflicting opinions which have made this one area of major confusion for brewers getting into liquid yeasts. for example i personally found chiller's thread confusing because of the "this jar, that jar" discussion which then went off into a disagreement about chemicals used to wash yeast with.

I'm looking to get a definitive idea of the easiest way of storing and re-using the yeast slurry from a brew for future batches, bearing in mind that a lot of newer brewers won't have access to the chemicals that have been mentioned in previous posts for washing yeast etc. Feel free to post pics of your own process to help out others.

This thread won't deal with splitting up new smackpacks or whitelabs vials, just storing and re-using the slurry.

We can use my latest yeast slurry for the experiment. It's a Wyeast 3068 which has spent 8 days in primary. I collected the slurry into a 2 litre starter bottle as per below:





as you can see, it has seperated out with the 3068 at the bottom.

so, without just redirecting us to a previous thread:

1. what's the best way to store this? can i split it up into individual bottles? do we need to remove the top bit first and if so, how?

2. what temps do you need to store the yeast under if being used:

within 1 week (can it stay at room temp in the starter bottle?)
within 8 weeks

3. finally, when it comes time to re-use the yeast, do you need a starter or can you just repitch ~100mls directly into the wort? is this determined by whether or not the yeast has been stored for a certain amount of time?

Cheers,

Hugh


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## Screwtop (6/6/07)

Given there is somewhere around 3 or 4 thousand brewers registered on AHB, asking for the best method is going to result in as many opinions.

Each will have their way, this is mine. Once the beer is drained/syphoned from the fermenter, swish the remaining beer, trub and yeast around so as it mixes into a slurry. Have a couple of sanitised screw top jars (pickled onion jars or suchlike) ready to fill with the yeast slurry. Just tip the fermenter up and drain the slurry out through the tap into the jars. Stop at 250ml (roughly the 10:1 rule) in the jar if you plan to re-pitch this yeast on the day (I've kept it in the fridge and repitched up to 5 days later without problems). Fill the jars and store in the fridge. Have used yeast stored this way for 6 months and more. Always make a starter to prove the yeast's integrity before use.


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## Jye (6/6/07)

Heres my process.

After primary fermentation I chill down to 0C for 24 hours and then rack into a keg. To store the yeast I use 2 to 4 L pyrex bottles that have been filled with water, boiled and then cooled. The water is tipped into the fermenter and swirled around to resuspend the yeast cake. I let this sit for 10-15 min to let any trub settle and then rack the yeasty water back into the bottle, trying not to disturb the trub like you wouldnt disturb the yeast cake when racking beer. I then chuck the bottle in the fridge with the lid screwed on. 

Before use I decant the liquid and chuck the yeast cold straight into the fresh batch of wort. I generally repeat this 3-4 times before starting with fresh batch of yeast.

I have found no problems if reusing the yeast with in a week. The last batch sat in the fridge for 2 weeks and took a bit longer to kick off but did its job in the end. Any longer than 2 weeks and I would be tempted to make a starter.


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## Stuster (6/6/07)

Screwtop said:


> Given there is somewhere around 3 or 4 thousand brewers registered on AHB, asking for the best method is going to result in as many opinions.
> 
> Each will have their way, this is mine. Once the beer is drained/syphoned from the fermenter, swish the remaining beer, trub and yeast around so as it mixes into a slurry. Have a couple of sanitised screw top jars (pickled onion jars or suchlike) ready to fill with the yeast slurry. Just tip the fermenter up and drain the slurry out through the tap into the jars. Stop at 250ml (roughly the 10:1 rule) in the jar if you plan to re-pitch this yeast on the day (I've kept it in the fridge and repitched up to 5 days later without problems). Fill the jars and store in the fridge. Have used yeast stored this way for 6 months and more. Always make a starter to prove the yeast's integrity before use.



This is my method as well. :super: 

One thing to consider with wheat beer yeasts is that they apparently do not store very well. Different yeasts will have different levels of viability after time in storage. Lagers apparently keep well, wheat beers badly. This is only what I've read though, no personal experience either way.


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## therook (6/6/07)

Am i understanding this right.....if you are going to repitch within a week you can just add the slurry, but any longer you will need to make a starter????

How long could you keep the slurry before it is not even worth making a starter

Rook


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## Stuster (6/6/07)

That's right. I'd say up to two weeks is ok, but I'd probably add more yeast in that case. I'm not sure how long you could keep it in this way, but certainly a few months is possible. The number of large jars in the fridge tend to get me to use some of them before they get too old.


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## Cortez The Killer (6/6/07)

I have put chiller's process in a numbered format so that it is easy to follow when actually doing it

I've used this with sucess upto about 3 months after the original harvest - but it is apparently good for longer periods

Also worth noting is that yeast stinks! :wacko: So don't be put off when reculturing the yeast - make a call whether the yeast is good by tasting and smelling the starter.

I might see it I have time to photograph the process next time I do it 

Cheers and thanks Chiller

===============================================================

1. The day before – prepare 2 litres of sterile water [boil for 15 minutes] and cool in the fridge in a sealable PET soft drink bottle.

2. Obtain 2 x 500 ml jars, a clean beer glass and 3 x 50 - 100 ml sample vials – sanitise all of these.

3. Transfer the beer off the cake and remove all the beer [not the yeast].

4. Pour 500ml of your sterile water into the fermenter and give it a very good swill around to mix the yeast and water. 

5. Collect enough of the yeast solution in the beer glass to almost fill one of the jars. Shake it really well and lightly seal it with glad wrap and set it in the fridge for about 10-15 minutes. The heavy material will drop. 

6. You can now pour the top 3/4 of the liquid into the other jar and top up with sterile water. Shake and set aside for 10-15 minutes. 

7. Repeat above and sanitise the first jar.

8. Repeat. 

9. Fill the sample jars 3/4 full with the milky liquid remaining, cap these and place in the fridge.

10. What remains in the larger jar can be used for your next brew [make a starter] or discarded.

11. Let the yeast settle out in the sample jars for 24 - 48 hours. 

12. You will now have a compact yeast layer and reasonably clean liquid on top. Remove the lid and pour off most of the liquid and replace with your sterile water. Shake well and let settle again for 24 hours. 

13. The liquid will now be quite clear, pour this off and replace with sterile water and return to the fridge. 

14. Check your samples over the next week and if the water shows any discolouration replace it with fresh sterile water.

These samples will remain viable for at least 12 - 18 months and maybe longer. I have used a Scottish ale yeast kept in my yeast farm that was dated 3 years old. It fired up over 2 days stepping up from 50ml to 150ml to 500ml.

I have used yeast over many generations maintained in this manner with absolutely no changes in character. Far beyond the mythical oft repeated homebrew law of 3 generations. The only danger and it is real is the danger of infection when harvesting yeast. Most All Grain brewers are competent at sanitation and the problem is small.

Don't forget when you use the last sample repeat the procedure. Another three samples will be waiting when you need them. You will probably have 3 - 4 favourite yeasts you use on a regular basis and this method will ensure you keep a healthy supply ongoing for a very long time.


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## Trough Lolly (6/6/07)

therook said:


> Am i understanding this right.....if you are going to repitch within a week you can just add the slurry, but any longer you will need to make a starter????
> 
> How long could you keep the slurry before it is not even worth making a starter
> 
> Rook



G'day Rook,
I've made active starters this year from slurry (Wyeast 1028) that I bottled back in 2005...I used Chiller's method and it works fine if you don't want to go to the next level and plate out the yeast or make tubes of the stuff.

IMHO - Any slurry thats less than 3 months old is good for a starter or if you have enough can got into the fermenter and I can confidently pour slurry directly onto the wort if it's less than a month old and have less than an hour's lag time.

Cheers,
TL


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## Jye (6/6/07)

Cortez The Killer said:


> Also worth noting is that yeast stinks! :wacko: So don't be put off when reculturing the yeast - make a call whether the yeast is good by tasting and smelling the starter.



Good point, always taste any water/beer you decant off. If it smells/looks off or taste funny then dont put it in your beer.


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## hughman666 (6/6/07)

excellent stuff guys, this is exactly what i was after.

jye, thanks for your example, that's what i'm doing at the moment.

cortez, thanks for unscrambling chiller's process, that makes it easier.

there should be very little confusion surrounding this subject now. perhaps this could be pinned as a simple howto?


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## matti (6/6/07)

Nice work Cortez,
2 questions.

Do you check the temp on sterile water? Or are you having room temperature as you leave the yeast to settle out?

What temperature are you storing the yeast at?

No need to freeze the yeast if this works eh?
matti


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## Darren (6/6/07)

www.wyeast.com gives a simple but comprehensive explanation for brewers. Best to follow the "breweries" protocol rather than the "home brewer" protocol.

Acid washing your yeast is very important IMHO. Unless you like infections?

cheers

Darren


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## chris.taylor.98 (6/6/07)

Ok thought I would add my 10c worth just to confuse you more

Yeast storage is all about ensuring you have the best posible yeast to pitch at the start of fermentation and is:
- In good health and has not already been "overworked"
- Is still mostly viable and not left to wallow in its own juices for 6 months.
- Has not regenerated over 20 times and is now somewhat different to the yeast you where expecting.

So ... don't expect if you store yeast for 6 months it is going to be particularly viable ( some say no more than 2 weeks but it really depends on the yeast strain you are storing ). If in doubt do a starter.

If you have already worked the yeast hard ( high gravity, under pitched, reused lots of times ) it is probably time to retire it and get a fresh batch.

Reusing yeast if done properly will actually result in better beer after 2-3 re-uses. Comercially brewers will go up to 10 or more times.

If you want to keep yeast long term and store a pure strain ( ie one that you can trust to be fairly close to what you want ) try yeast slants. They are a bit of stuffing around but you will end up with better quality yeast.


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## chris.taylor.98 (6/6/07)

ditto with Darren.

Yeast re-use needs to be very carefully managed re sanitisation, and has a high potential for introducing infections. Another reason not to try and overdo it. (btw you don't have as big an issue with slants)


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## kook (6/6/07)

Jye said:


> To store the yeast I use 2 to 4 L pyrex bottles that have been filled with water, boiled and then cooled.



Just curious, I've got some spare 1L schott bottles like that, do you boil them in a pot (like a double boiler), or do you place them directly on a stove top? Or are you doing something completely different ie microwave or pressure cooker?

Are the blue lids able to take high temps?


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## xtrabyte (7/6/07)

Darren said:


> www.wyeast.com gives a simple but comprehensive explanation for brewers. Best to follow the "breweries" protocol rather than the "home brewer" protocol.
> 
> Acid washing your yeast is very important IMHO. Unless you like infections?
> 
> ...



The correct link is http://www.wyeastlab.com/


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## Cortez The Killer (7/6/07)

matti said:


> Nice work Cortez,
> 2 questions.
> 
> Do you check the temp on sterile water? Or are you having room temperature as you leave the yeast to settle out?
> ...



I try to work with room temp

I put the havested yeast in the fridge

Freezing yeast from what I've read does seem to have some benefits - but does involve a little more work

Cheers


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## Kingy (19/6/07)

i just finishing racking a beer and was planning on reusing the yeast tomorrow. As im not prepared with sterile water etc etc. Can i just sanitize a schooner glass and a measuring cup and scoop the slurry into the glass and cover with a glad wrap and a rubber band?

also can i boil and cool some water and make a starter with all this yeast along with 1 litre of water and 100grams of dme this afternoon by transfering into a bottle?

hope this makes sense
cheer,kingy

p.s do i store in the fridge or is it ok at 12 degrees in my shed untill i plan to pich it tomorrow arvo


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## Stuster (19/6/07)

Yep, storing it like that will be fine. Or just sterilise a glass jar, swirl the fermenter once the beer is gone, and pour the yeast cake into the jar.

There's plenty of yeast in the yeast cake. There's no need to make a starter. Keep it in the fridge.


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## Kingy (19/6/07)

could i split this slurry into 2 equal amounts to add to 2 differant batches (1 tomorrow and 1 on saturday) or should i use the whole lot seeing as tho this is the first reuse of the slurry. And then wait till next time round before splitting it up and storing and making starters.

this is an area of brewing i need to brush up on as ive been forking out to many $$ on yeast lately

cheers kingy


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## Hutch (19/6/07)

Kingy said:


> could i split this slurry into 2 equal amounts to add to 2 differant batches (1 tomorrow and 1 on saturday) or should i use the whole lot seeing as tho this is the first reuse of the slurry. And then wait till next time round before splitting it up and storing and making starters.
> 
> this is an area of brewing i need to brush up on as ive been forking out to many $$ on yeast lately
> 
> cheers kingy


Kinky,
You will be fine splitting the slurry into 2 halves - in fact I would recommend against pitching the whole yeast cake into the next brew, unless you want to see what yeast looks like sprayed all over your ceiling (yes, this happened to me with 1 cup of Wyeast 1056 slurry).

I've read numerous times that a half cup of slurry is plenty to repitch, provided it is not stored for ages before repitching.

Hutch.


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## Stuster (19/6/07)

Slurry from one batch should be fine for two more batches if they are fairly similar in gravity and volume. Yeast's far too expensive to buy fresh each time, with liquid yeast anyway. As long as you are careful with sanitation, you should be fine and then you can repitch good quantities of yeast. It's really easier than making up starters all the time IMO.

Edit: Mr Malty is a great calculator for how much yeast to pitch.


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## Kingy (19/6/07)

cheers guys
i thought i worked it out, i just needed some reassurance incase i ruined my third AG tomorrow. All that hard work and time to have a batch ruined would piss me off.

To have any batch ruined would piss me off  

cheers kingy


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## Cortez The Killer (19/6/07)

How long does the slurry keep in the fridge?

Or better still how long do people keep the slurry in the fridge before use / discarding?

Cheers


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## Jye (19/6/07)

Some brewers say they have reused a slurry after months. A couple of days ago I discarded a slurry because it wasnt quite right and it had only been in the fridge for 5 days, but the beer it cam from is fine.

In the end this is something your going to have to decide.


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## therook (19/6/07)

Jye said:


> Some brewers say they have reused a slurry after months. A couple of days ago I discarded a slurry because it wasnt quite right and it had only been in the fridge for 5 days, but the beer it cam from is fine.
> 
> In the end this is something your going to have to decide.




Jye, was you slurry under some sterile water?

After a couple of months i have been told you can use the slurry but should make a starter....is this correct?

Rook


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## Cortez The Killer (19/6/07)

I've re-used slurry after storing in stubbies for 1.5 months and while it smelt a little bit like veginite - but fired up fine in the starter

So my question is - what does the vegimite smell actually mean - is it yeast autolosis or something else? And is it a basis for discarding refrigerated slurry?

Cheers


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## Jye (19/6/07)

therook said:


> Jye, was you slurry under some sterile water?
> 
> After a couple of months i have been told you can use the slurry but should make a starter....is this correct?
> 
> Rook



This one wasnt under any water since I had planned to use it so quickly. If a slurry had been in the fridge for over a month I would make a start to make sure it is still viable and to give the yeast a bit of a wake up call.

Cortez, did any of the vegimite come through in the final beer? If not you might be ok. But I wouldnt be using a slurry that has changed taste while sitting in the fridge.

Cheers
Jye


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## Cortez The Killer (19/6/07)

Nah 

I made a starter and tasted that - no vegimite smell or taste

Beer was fine

Cheers


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## Stuster (19/6/07)

I've also smelled vegemite in yeast that was stored in the fridge. I was a bit dubious about it, but went ahead and made a starter, which didn't smell or taste of my breakfast topping. I used it in a beer and it appeared to come out fine, so I think as long as you don't pitch a whole slurry of vegemite yeast, you are probably ok.


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## Duff (19/6/07)

kook said:


> Just curious, I've got some spare 1L schott bottles like that, do you boil them in a pot (like a double boiler), or do you place them directly on a stove top? Or are you doing something completely different ie microwave or pressure cooker?
> 
> Are the blue lids able to take high temps?



Hi kook,

I autoclave my agar media in the blue lid Schott bottles at Uni, so they handle the high temperature fine.

Cheers.


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## razz (19/6/07)

That's very interesting. I always thought it meant autolysis, so I've thrown a few out.


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## TidalPete (19/6/07)

Duff said:


> Hi kook,
> 
> I autoclave my agar media in the blue lid Schott bottles at Uni, so they handle the high temperature fine.
> 
> Cheers.



Lucky you Duff! Great to have access to a free autoclave. :super: 

*Queensland Rocks in State of O!* ---- off-topic but true. :super: 

:beer:


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## Stuster (19/6/07)

razz said:


> That's very interesting. I always thought it meant autolysis, so I've thrown a few out.



It might be autolysis, but I've done this from small quantities of yeast in a vial and those have gone on to make a starter which has smelled and tasted fine. That amount of autolysis in a whole batch will be almost nothing I guess. It's certainly better to throw it out though, than ruin a batch with off yeast. I've thrown out a few vials that didn't look too good.


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## matti (19/6/07)

I have been assured time after time that do not trust your nose with yeast.
GIVE IT A TASTE
I don't know about vegemite though.
spread it on the brew


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## Brewtus (19/6/07)

Cortez The Killer said:


> How long does the slurry keep in the fridge?
> 
> Or better still how long do people keep the slurry in the fridge before use / discarding?
> 
> Cheers



I keep my slury in the fridge. I tried one after two or three weeks (2 batches) and it was fine. I tried one the other week that was about 4 months old with no luck, had to pitch dry yeast. I did another that was 6 months by pouring it into a 2lt bottle with 1 lt of wort. it took off so after 2 weeks I drained the wort, rinsed it in clean water and it is now a happy Belgian specialty yeast in a Cascade porter kit with a tin of coopers amber malt, 300g of BH1 and 400g of golden syrup (OG 1055) bubbling away.


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## Kingy (21/6/07)

ok so ive got a brew thats been fermenting for about 2-3 days and therez krausin and i want some yeast for todays brew that im doing.
Do i just scoop the kruasin off and into a sanitized jar - say about 1 cups worth and seal the jar at about 12 degress untill ive finished brewing and pitch this this arvo?

cheers kingy


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## Stuster (21/6/07)

I've never top cropped a yeast, but that is how you do it. You could just wait till you need to use it before harvesting it of course. If it's not a top cropper (or even if it is) you could just drain off a litre of the fermenting beer and transfer that to the new beer. Which yeast are you using though?


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## Kingy (21/6/07)

the fermenting batch has a white labs mex lager yeast that was slow to start so i dropped a craftbrewer swiss lager in as well s189 cheers. And im planning on reusing it on a low alcohol beer. Of 1030-1036 gravity est.


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## Stuster (21/6/07)

If it's a lager, you probably don't want to top crop. I'd say you need to transfer at least a litre of wort if it's a low gravity lager.


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