Reusing slurry

[schmurf]

I can't remember I've reused slurry before, but thinking about doing it on my next brew. I've read that it's not good practice to go from a higher ABV beer to a lower ABV beer, but is this a total no no or are there room for interpretations? My next brew will be the same beer/recipe that's currently fermenting, but I'm going to lower the ABV some, from about 5.5% to about 4.3%. Would this be ok or bad? Any recommendations about this?

 

[rhys333]

It's just best practice to go from lower to higher abv, but it's fine to go the other way as long as it's not an extreme drop (say from 8% to 4%). It's also a good idea to use the slurry within a few days, but again, I've gone weeks and and even months without issue.

You don't need a lot of slurry either. I estimate 1B cells per ml of slurry, with 200B needed for 5 gallons of 5%beer. So 1/3 of a pint sized mason jar is plenty.

 

[IslandLizard]

What he says.^

Yeast from low gravity fermentations can be reused/repitched almost indefinitely. Your case is likely still safe territory. You could always make starter with some of it, especially when it has been stored (refrigerated) for longer times.

It's actually discouraged to reuse yeast from high gravity (high alcohol) fermentations, but yeast from a 5.5% ABV brew is not considered high gravity, and should be fine to reuse in a 4% beer.

Anything above an OG of 1.060-1.065 is considered high gravity territory, but I've repitched slurries from those in similar gravity beers (of 1.060-65) several times over, with no issues. 1.075 and up definitely is getting too high for reuse, although...

 

[schmurf]

Thank you guys, I like the answers

 

[odie]

I think it's more of an issue with flavors from the previous beer than the gravity of the previous beer. You would not want to do a light pilsner with a doppelbock yeast harvest. Typically the higher gravity beers are also more bold in flavors and darker color...."typically"...

I've reused T-58 from a higher OG beer with no issues. But Typically I have enough beers of different types going on that I have enough lower OG harvests to not even bother trying to save the yeast from a complex beer. I'd rather have reuse yeast from plain jane beers.

One harvest can get you 2-4 samples for the next beer. And one of those will net you another 2-4 samples. You yeast stock plie will multiply fast.

 

[fragged]

I think it's more of an issue with flavors from the previous beer than the gravity of the previous beer. You would not want to do a light pilsner with a doppelbock yeast harvest. Typically the higher gravity beers are also more bold in flavors and darker color...."typically"...

I've reused T-58 from a higher OG beer with no issues. But Typically I have enough beers of different types going on that I have enough lower OG harvests to not even bother trying to save the yeast from a complex beer. I'd rather have reuse yeast from plain jane beers.

One harvest can get you 2-4 samples for the next beer. And one of those will net you another 2-4 samples. You yeast stock plie will multiply fast.

This is my take on it too. While maybe ABV/OG comes into play once it gets up there, I find it more likely that if I'm fermenting something high OG, it has strong flavors/colors. Almost certainly stronger than a lower OG.

I'm thinking a rule of thumb may not be best either. Flying by the seat of my pants here - but I would look at ABV per yeast strain, rather than a blanket number/range. If the tolerance of the yeast I'm using is 8% and I make an 8% beer with it, I'd worry about using it on a 5% next.

 

[odie]

I kinda look at it in terms of three or light/med/heavy.

I will reuse a dark beer or higher ABV yeast in a med color beer or med ABV beer. Or from a med beer to a lighter color/ABV beer.

But never use a Dopplebock harvest to make a Pilsner. I'll use a Pilsner harvest to make a Dopplebock.

I'll only go one step down but 2 steps up.

But really, if you fully decant the old beer off the top of your harvested slurry, there isn't much that's going to taint your new beer. It's maybe a 1/4 cup of slurry or less in 5+ gal of wort. Unless it's the lightest of beers there is probably not much to worry about.

 

[moreb33rplz]

I do this a lot. I never re-use a dry hopped slurry. I don't really pay any mind to if a subsequent beer has a higher OG or not, but I haven't ever re-used a slurry from a 'big' beer (1.070+ ish).

 

[twd000]

there's no way the flavor from a previous batch would affect the current batch. 1/3 of a pint of slurry is 5 fl. oz., or 0.8% of the volume of a 5-gallon batch. You could toss in some hot sauce at 0.8% and not taste it

 

[Oleson M.D.]

We re-pitch slurry harvests on a routine basis. Up through 10 or more generations. Never had any issues at all. You will be fine. And we always over-pitch. About a quart of slurry per 5 gallon batch size.

 

[IslandLizard]

About a quart of slurry per 5 gallon batch size.

A quart? Are you kidding?

 

[Oleson M.D.]

When it comes to making Gold Medal Award Winning beers, we never kid.
Yes, one quart per 5 gallons. Always.

 

[odie]

That's a lot of slurry...I usually only get a pint at the most. That's if I save the entire yeast cake. But my fermenter slurry is almost pure yeast, no trub, because of my wort straining techniques.

 

[DBhomebrew]

Out of a 3.75G batch, I'll collect three half-pint jars. Each of those will compact into about 1/2c of cake under 1/2c of protective beer. I'll pitch one jar into a new batch 1.040-65. North of that, I might pitch two.

 

[CascadesBrewer]

When it comes to making Gold Medal Award Winning beers, we never kid.
Yes, one quart per 5 gallons. Always.

I hear Denny Conn talking about saving yeast slurry in 1/2 gallon jugs and I get the impression that he pitches one of those. Maybe he makes bigger batches.

I usually pitch a 16 oz jar of yeast slurry into a 5-gallon batch. I have played around with limiting the amount of trub that goes into my fermenters, and it was either too much time/effort or wasted too much beer. That means my harvested slurry tends to have lots of trub. At one point I figured that my entire yeast cake of a typical batch filled four to five 16 oz jars. I figure one 16-oz jar is about 1/4 of the yeast cake which should be about the right amount (for a low to medium gravity 5-gallon batch of ale).

 

[Oleson M.D.]

Our harvested yeast is 99% pure, without very little trub. I run my chilled wort trough a mesh filter as it goes into the fermenter. Plus we use whole leaf hops, and the boil kettle has a triple filter in the bottom. What we get is clean, very clean.

 

[DBhomebrew]

I hear Denny Conn talking about saving yeast slurry in 1/2 gallon jugs and I get the impression that he pitches one of those. Maybe he makes bigger batches.

Maybe he pours off the old beer, adds fresh wort, and gives it a mighty shake.

#SnS

 

[Beermeister32]

When it comes to making Gold Medal Award Winning beers, we never kid.
Yes, one quart per 5 gallons. Always.

Is your slurry the yeast cake from a previous batch or have you washed the yeast?

 

[odie]

Our harvested yeast is 99% pure, without very little trub. I run my chilled wort trough a mesh filter as it goes into the fermenter. . What we get is clean, very clean.

I do the same. Super clean wort and pure yeast cake to harvest after fermentation.

 

[odie]

Maybe he pours off the old beer, adds fresh wort, and gives it a mighty shake.

#SnS

this is exactly what I do. My yeast harvests contain beer. when they sit in the fridge the yeast compacts to the bottom and clear beer sits on top protecting the yeast until it's time to pitch. I decant the old beer, ass freash wort and shake up the cake before pitching.

 

[odie]

Is your slurry the yeast cake from a previous batch or have you washed the yeast?

don't wash the yeast. just swirl up the fermenter after you rack the beer and pour the stuff into pint jars. the residual beer will settle out on top of the yeast and help preserve/protect it until it's time to use it.

Washing just adds risk. If you have lots of trub in your yeast cake then you might consider washing it or filtering your wort BEFORE fermentation.

 

[BeerAndTele]

don't wash the yeast. just swirl up the fermenter after you rack the beer and pour the stuff into pint jars. the residual beer will settle out on top of the yeast and help preserve/protect it until it's time to use it.

Washing just adds risk. If you have lots of trub in your yeast cake then you might consider washing it or filtering your wort BEFORE fermentation.

Agreed with Odie.

Chris White of White Labs says the same thing (in most circumstances) in an interview I ran into recently. I'll put the link below. The yeast washing discussion starts at 2:35.

 

[Beermeister32]

I run my chilled wort trough a mesh filter as it goes into the fermenter.

What type of mesh filter do you use?

 

[odie]

What type of mesh filter do you use?

Don't know what he uses but I use 5 gal bucket strainers. Easy to find on Amazon or ebay. Around 200 micron is what I think mine are. Also you can use those nylon honey strainers. They are cone shaped with a metal ring, keeps the bag from getting pulled into the bucket. The plain jane strainer bags will just collapse.

 

[seatazzz]

About an hour ago I pitched 1 cup of lallemand kveik (dry) 1st generation slurry into a 1.051 beer (at 110°, horey clap), and it's already taking off. I also don't "wash" my yeast (big fat PITA to do) but just let the beer settle out on top to keep it happy. I've been using slurries for about 4 years now and will continue to do so; not only the savings of $$, but proven yeast is PROVEN; if it came out of a good finished beer, it will continue to produce good beer as long as you treat it right. And using slurry pretty much negates the need of a starter; you're starting with plenty of good cells so no starter is needed. In my brewery I use only three strains; Nottingham, which has never done me wrong for ales; S23, for lagers; and now the Lallemand kveik. Last summer I used Imperial Loki but it went south after 3 generations (possibly my own error). I especially like using slurry for my lagers; tradition tells us that overpitching lagers is the way to go, and using slurry you're getting a lot more than you need.