Using slurry from one batch for another

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MikeBusby

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I am generally happy to use a new pack of dried yeast for each batch, but on this occasion I am currently fermenting a hefeweizen and will be starting new new batch of hefeweizen straight after (I like hefeweizen!).

I have read about people using the slurry from one batch for the next batch. Is this a good opportunity to try this out and, if so, how does it work?
 

Hanglow

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Yes it's a good idea

As you are doing it straight after, I'd use 1/4 of the left behind yeast. Most proper hefeweizen yeasts are strong fermenters, so you could get away with less if you are oxygenating properly, but that amount should guarantee you a strong ferment
 

MikeBusby

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Yes it's a good idea

As you are doing it straight after, I'd use 1/4 of the left behind yeast. Most proper hefeweizen yeasts are strong fermenters, so you could get away with less if you are oxygenating properly, but that amount should guarantee you a strong ferment
So, I don’t have to do anything apart from remove 3/4 of the trub? And no need to clean out the FV first?
 

Hanglow

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I'd still use another cleaned FV, but a lot of people do just reuse the same one. Depends how confident you are with your sanitation.

By doing it this way you are taking the guessing out of how much yeast you use, as if you are taking the slurry out and measuring it in jug and using a calculator then you need to approximate how compact it is, what % is not yeast etc. With 1/4 you know you will get 2 generations of growth to get the same amount of yeast that you had at the end of the original fermentation, which is a reasonable amount of growth in a beer
 

LED_ZEP

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I'd be a little cautious how many times you do this if your going back to the same FV, once or twice should be fine. I've got a ferment that's now on it's 6th generation (a sugar wash with corn), in this instance your hoping for a slight infection for flavour (like sourdough). This gets stronger with each ferment as the yeast culture evolves, this is great for what I'm doing but not really what you want for your beer.
 

Hanglow

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Yeah I definitely wouldn't use an FV without cleaning it multiple times in a row, especially if it's a bucket which would be opened multiple times
 

Cwrw666

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Even if your sanitation is good, if there's any cruddy krausen remains at the top of the FV, this is a good place for mould development. So, yeah, use a new FV, fill it with wort and dollop a few spoonfulls of the old yeast cake in there.
 

MikeBusby

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Thanks, guys. I plan to do this only the once and mainly because it is the exact same beer recipe being brewed.
 

phildo79

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I used the whole yeast cake from a pale ale to make another pale ale. Worked out fine. I then used it to make an imperial stout. Took longer than it would have normally but got there in the end. I didn't bother cleaning the FV for any of them and everything was fine. I then gave the FV a good clean and dumped the cake. I will be doing this method from now on but be mindful of the target ABV's.
 

obscure

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I used a cup of slurry from a Yorkshire Bitter in a Barley wine worked great (arguably given the low gravity of the Yorkshire Bitter it was almost like a starter 1.036 or so, 9L batch. I did however use a clean fermentor, meant I could put the new batch in a clean fermentor keg the bitter and then add the slurry straight away helping to minimise the risk of contamination.

Worked great and a really easy way of reusing yeast.
 

phildo79

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I should perhaps point out that I use a pressure FV. If I was just using a brewing bucket, I would probably remove the cake and use a clean bucket.
 

Nicks90

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I regularly reuse yeast. But as I rarely brew back to back, I tend to just dump a pint of cool boiled water in the bottom of the emptied fv and swill it around. Then pour the runny trub liquid/yeast in to a sanitised 500ml pet bottle and bung it in the fridge.
I've left them in the fridge for months before now and they've always worked.

Just remember to label them, as I have occasionally forgotten what yeast is in what bottle and had to go with the 'be reeet' and chucked it in anyway
 

Pavalijo

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I’ve read about “cleaning yeast” to reuse it, but never seen a thread as to how this is done.
What is suggested here is that it’s not necessary to clean it - but am I missing something? And if so how do you harvest trub and “clean” the yeast?
One problem I’ve had is that several kits have fermented out very slowly 3,4 and even 6 weeks once. I have thought that it might be a good idea if following one brew with another that uses the same/similar yeast that I could supplement the meagre few grams that comes with the kit with some yeast harvested from the last brew - but didn’t do it as I didn’t know how to “clean” it.
Any advice welcomed!
 

Nicks90

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Would you then use an entire 500ml bottle in a brew, @Nicks90 ?
Yes.
I reckon there is probably 500ml beer left in the bottom after bottling and add another 500ml cooled boiled water. There's probably (in volume) maybe 500-1000ml of trub. The oldest and deadest yeast and gunk that made it from the kettle should be right at the bottom and the newest freshest cleanest yeast at the top of the trub. So I pour my extra water in and swirl it about.
The slurry that I pour in to my bottle should consist of the freshest stuff, as the base of the fv still has a layer of trub attached to it.
So whilst I am in theory taking a 1/4 of the total trub - which should be more then enough - I am hoping I am taking the freshest and cleanest 1/4 and leaving most of the hop debris and dead stuff behind.

As with all things, without a microscope and a cell count, you have no idea how much you actually have, but I can't see how it would be any less than a healthy 11gm dried sachet of yeast! My brews have all gone off like a shot within 12 hours using this method, so it must be effective
 

krispn

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I've just bottled/kegged a small batch of 7% stout and plan to brew another 19l batch of my 5% stout this week - I currently have placed the Imp stout FV (Fermzilla pressure FV) back in the brew fridge at 4c My plan was when the new stout is ready to commence fermentation scoop out some of the trub (aiming to take from the top leaving the dead stuff on the bottom) pitch that into a new cleaned FV and then wash out the previous one.

Would I be better off washing the yeast or does the above plan sound legit? The pressure FV has not been opened and all kegging/bottling was done under pressure.

Any info appreciated
 

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