Reusing Yeast Directly From The Fermenter

[Ryan WABC]

I was curious when I read about pitching a new brew onto an old yeast cake, so I'm going to give it a go. I'm going to do two lagers with the exact same preparation and ingredients, using Saflager W-34/70 for the first, then pitch the second straight on top of the yeast cake of the first. I'll be interested to see if there is any difference in flavour between the two.

 

[timryan]

Sounds good but what about the mess around the top of the fermenter? Could that infect the beer?

 

[RdeVjun]

Sounds good but what about the mess around the top of the fermenter? Could that infect the beer?

Nope, that's just krausen residue, fairly pure yeast and a few fermentation by- products, so nothing to worry about. I just leave it be, no point in trying to clean it off and potentially introducing a source of infection.

 

[cdbrown]

I don't know if I'd dump directly onto the yeast cake. I'd want to cap a cup of yeast slurry and pitch it into a clean fermenter. Couldn't pitching on the cake be detrimental just like overpitching of yeast? Cake will be full of dead yeast cells, hop material and other proteins which have dropped out of the previous beer. For me I'd clean the fermenter first and start fresh.

 

[brettprevans]

this like most things in brewing is about your own preferance and risk appetite. there are the gold plated, absolute best etc methods and then there is reality. there are varying degrees of time poor people, can be arsed, happy to take a chance etc people out there that will do less than the perfect methods. you just have to be aware of the risks.

Ive pitched directly onto whole yeast cakes no issues, ive used non sanitised bottles to collect yeastcask then dumped the whole thing on top other beers, trub and all. no problems etc. im happy to risk it. ive also got gen7 yeasts that im using which is a good few generations over the reccomended reuse. they are ok. all that being said ive seen people have infections, have yeast mutate and send off flavoiurs etc. pick whats right for you and suits your risk appetite.

asking the questions, reseraching etc so you have the information is a great start to understanding wat your prepared to live with.

if i didnt have 3 kids, an insane job and a masters to do, id probably wash my yeast and have better pitching and sanatation procedures, but i dont have the time so i take some calculated risks based on past experiance (like infections etc)

 

[Nick JD]

Even though US-05 is not too expensive I usually run mine for two or three generations before going onto fresh stock.

I took S189 to generation 4 in a keg I'm serving now, and there's a few hints of it's age showing through. Was a bit sulphury in the fermenter and is still there in the keg a tiny amount (which is out of character for 189). It's less lagery too - maybe hints of esters popping up. It's hard to put my finger on it, but the beer is just less good.

I also reckon 3 generations is the best time to retire your yeast.

When I want to revive a yeast that's months old (been sitting in a 300ml PET bottle in fridge) I like to make a starter from it and then "top crop" the starter to get at the fresh generation and leave the vegemitey trub well behind. Some yeats you can actually do a proper top-crop of the starter krausen, others I pour off the active portion and ditch the trub. The second starter is full of rearing yeast - or I've simply decanted into the fermenter before.

 

[timryan]

See I believe that I would be best to collect the trub in a glass and cover with cling wrap then clean out the fermenter and once done and the next batch mixed I would dump ontop.. I worry about the residue from the last hop having an effect on the new batch.. Although if I follow it up with a similar hop that might add something to the brew..

 

[rich_lamb]

Good to see so much of that precious yeast being reused! I've been doing this in various ways nearly since I started - sure, I can afford new yeast, but I hate to waste stuff.
Here's my 2c:
- I don't bother to wash it, as I reckon the chance of adding infection (in each and every transfer) vastly outways the benefit of having no trub in there. The way I see it, so what if you add 100ml of trub to a batch of new beer (that has much more trub in it anyway). ie. what exactly are you scared of adding with this trub? I used to wash the yeast, but gave up. That said, when I was no-chilling my wort was pretty clean as it filtered out o fthe kettle, so the yeast looked great. My recent batches the yeast looks rubbish, but I aint payin' it to be pretty (I used it just the same).

- I acid washed once, to try to eliminate any bacteria, but as you cant really know how effective you're being I was dubious about it's value. I do have the low pH papers now so I can do this with more accuracy but I'm not planning to add it to my process

- I typically only reuse the yeast for about 3 batches; this is for two reasons. First is that's typically the number of beers I want to make with that single yeast for a year or so, second is the concern of building up infection levels in the yeast (ie. a beer safety concern) which others have mentioned. I don't see any reason to push the limits established in the current dogma as to how many reuses you can get.

- I don't reuse beyond a gravity of about 1.065, bit of an arbitrary limit, but the reasoning for not reusing yeast from higher gravity beers seems pretty sound to me. I do try to roll from lighter to darker beers, but it's not a rule - I have done it the other way. You have to ask yourself "why" when you hear suggestions like dont-reuse-yeast-from-dark-beer. Basically it's a suggestion; to prevent you from darkening the second beer. But somewhere along the line it becomes a rule. If my second beer is not going to be greatly affected by a couple 100ml fo darker beer I'll happily go for it as the advantages outweigh the cost.

- I try to reuse across adjacent batches, so the yeast is only in the fridge for a few days. Occasionally I store it for a month or more and then I just do another starter to condition it up a bit. You will notice the yeast going darker the longer you store it, which I gather is just a slow autolysis (even sleepy yeast has gotta eat).

Basically I just use a sanitised cup and funnel to get yeast from the bottom of the fermenter at bottling. If you really don't like the trub in the sample you could swirl it before you pitch and let it settle for 5 minutes before pitching off the top. I cap 'em and sit them in the fridge - capping is not a problem for a few days. Reusing yeast is basically the same as making a starter in some ways - just a very big starter. I've actually made batches of a smaller beer to get enough yeast for a high-gravity brew.

 

[timryan]

From reading I think the best option is too collect some trub and empty and sanitize the fermenter then mix the new batch and re-add the mixture... This would be done on the same day within a matter of hours... Using a glass jar and cling wrap.. Might be able to collect a few for and fridge them for later brews...

 

[yum beer]

I used my first slury last weekend.
I bottled a kit draught early last week and collected 2 jars of slurry...swirled fermenter with 1/2 litre beer still on top then put into fridge.
Friday i put down a Black Rock Dry Lager, Saturday I had to go to Wollongong for the weekend and when I checked on it Saturday morning, 24 hours later..nothing, no krausen, no sign of Co2, no change if SG. I pulled a jar from the fridge, poured off the beer on top and pitched about 200ml of slurry, leaving some thickish looking crud on the bottom of the jar.
Got home Tuesday, brewing away like a champion, great krausen, smell good and tastes the goods.
Dont for sure if its only the slurry doing the work but I am pretty confident the kit yeast didnt fire.
I have always been a little concerned about using the slurry, but I wasnt losing a whole batch to infection if the kit yeast didnt kick on. Seems all is fine and I am happy to know that I can safely reuse my yeast and save a little more cash. I do lagers mainly and the yeast cost adds up.
Cheers to everyone on here for information and guidance in relation to reusing, washing, rinsing, pitching yeast.

 

[DKS]

If using the full yeastcake, temp control is important . A vigorous fement raises temps so watch the first 48hrs or so. Using this method has caught me out recently not using controlled fridge because of low ambient temps.
Daz

 

[Wolfy]

Good to see that many people are or are considering re-using their yeast, and there are so many ways to do it that there is not any right or wrong way, just what works best for you.

Re-using yeast - whatever way you do it - from the bottom (yeast cake) or top (cropping) of the fermentor - will not introduce any new contamination or infections that are not already in the previous beer (assuming your re-use procedures are sanitary). If you've been careful with your sanitation when brewing and fermenting the previous beer, there should be minimal risk, however since we don't brew in lab-conditions and only sanitize and not sterilize there is always some risk of infection. When healthy yeast is pitched at a good rate, it should out-compete most infections, the yeast will then do their best to create conditions (alcohol content and pH) to make life difficult for any such infections, so that helps minimise the risk.

 

[jyo]

I don't know if I'd dump directly onto the yeast cake. I'd want to cap a cup of yeast slurry and pitch it into a clean fermenter. Couldn't pitching on the cake be detrimental just like overpitching of yeast? Cake will be full of dead yeast cells, hop material and other proteins which have dropped out of the previous beer. For me I'd clean the fermenter first and start fresh.

Good discussion here^
I'm only just starting to get into yeast management (in the last 6 months or so) and I've only dumped onto the yeast cake twice.
The first time was with US05 and the resulting fermentation required a blow off tube, so massive over pitch!
I always use a clean fermenter now (and about a cup of slurry). It makes my OCD feel much better.

 

[ekul]

I find it really surprising that people don't reuse yeast. Even if you're using dry yeast thats $5 a brew. When i empty a brew into a keg i swirl the remiang beer to get the trub nice and fluid, then i drain as mcuh as i can so that about a cups worth is still in the fermenter. Then i'll throw some new wort on top. I figure the less i touch the yeast the less chance i have of introducing infection.
Brewing like this means that i never run out of beer (well sometimes i do) which means that the beer gets lots of time in the fermenter to clean up after itself. I have a three fermenters that rarely get washed, i always have a coopers yeast, a US05 fermenter and a lager fermenter, the lager fermenter is in a different fridge.

 

[parrja]

Grolsch swingtops are great for storing yeast slurry for your next brew! I usually keep two from each brew for later reuse.

 

[timryan]

I think I'll do the sanitize glass jar and the clean out the fermenter then mix the wort then add the trub.. It seems to be the best way to go.. Then the fermenter will be sanitized.. Then if something goes wrong I can then add us 05 on top.... Looking forward to the end of fermenting... About 20 days haha

 

[pdfarrell]

As a noobie yeast recycler (I asked alot of questions earlier in this topic), I'd like to share my experience since then.

* Had a brew fermented with US-05.
* Syphoned off Angel's Piss into keg.
* Fermenter contained yeast cake and a wee bit of Angel's Piss left in it, which I swirled to get a nice creamy mix.
* Poured (through the tap) the said slurry into 3 x 150ml sanitised screw-top plastic containers. (from Reject Shop ~ $1.50ea).
* Put 2 of the 3 slurry filled containers in the fridge.
* Cleaned and sanitised fermenter and dropped another batch of wort into it.
* Poured entire contents of remaining slurry container on top.

New beer turned out fine.

* Made more wort, did not harvest yeast cake from new brew.. used one from the fridge.

This beer turned out fine.

* Made more wort, did not harvest yeast cake from new brew.. used one from the fridge.

This beer turned out fine.

65+ litres of beer, using $6 of yeast. Good enough economics for me.

Next wort got fresh batch of yeast.

A big thankyou to the people that took the time to answer my questions, however basic they may have seemed.

 

[timryan]

G'day cus thanks for the info... My next brew I will reuse my us05... Ad I'll comment on how it performs... I don't think I will use more than 3 times....