Reusing yeast cake the lazy way?

[iambeer]

This might sound like a dumb questions but here goes..

I want reuse the yeast cake from a carboy I just siphoned beer out from.

Besides possible infections, are there other reasons I should not do this?

How likely am I get infected if I do this?


Thanks

 

[cheezydemon3]

The beer would be fine, just not the best the world has ever seen.

Over pitching, not infection is the problem.

 

[iambeer]

The beer would be fine, just not the best the world has ever seen.

Over pitching, not infection is the problem.

Thanks for the response but what is over pitching? Is that related to yeast mutating or.. stress (do know what yeast stress is either actually) and off-flavors resulting from this?

Also why wouldn't it be the best beer? For the same reasons or another reason?

This would be the second batch. Thanks in advance.

 

[NordeastBrewer77]

Over pitching means using way too much yeast. It can cause a thin feeling/tasting beer, along with other off flavors.
That beer flavor, a lot of that is produced during the early, reproductive stage of fermentation. When you pitch wort onto an entire cake, there's really no need for the yeast to reproduce since there's already enough yeast to ferment the beer. So what you get is beer, but it may lack a lot of the qualities we look for in a good brew.
What I do with a cake when I'm lazy and don't want to wash is carefully and cleanly pour some of it into a jar to use within the next few days. It's always better to wash your yeast, but if you're reusing it soon, you can just save part of the cake and pitch that.
Check out MrMalty to see how many ml of yeast you'll need for your beer.

 

[iambeer]

I wish I hadn't waited til last minute but I'm glad I checked with you guys. I guess I'll toss it since I'm out of time. Thanks

 

[brewit2it]

I think the problems with overpitching are like a lot of things in brewing, good in theory but hard to define in practice. I pitch on yeast cakes frequently. I usually poor some of it out first but not always and cant notice any difference. I do follow certain practices when pitching on a cake though. I go form a smaller, less hopppy beer to a larger more hoppy one, PA to IPA for instance. I make sure to aerate well, and I make sure temp control keeps fermentation at the low end of the range (low 60's basically). By following this I have seen no off flavors from the practice.

 

[YeastHerder]

From what I've read the potential problem is that putting the yeast through a round of fermentation can change them so that what you are using the 2nd go-round isn't really identical to what you were using the first time.

So far I've only thought of one specific example of what could be happening and they are called "petite" mutants. It goes something like this: you pitch healthy new yeast into a batch and they take off quickly because they can use O2 that is in the wort that lets them grow faster. (this is why we go through the trouble of aerating our wort before pitching the yeast)

The O2 gets depleted quickly as the yeast proliferate, and the bulk of fermentation kicks in. However, the absence of O2 allows a specific type of mutant, called a "petite" mutant, to flourish. Petite yeast have lost the ability to use O2. Normally this is tough luck for the poor sickly petite mutant, but its not a big deal in your fermenter since there isn't any O2 around anyway so the petites probably work just fine during fermentation. Come the end of fermentation, our yeast cakes probably have quite a few of these petites in it. So, if you pitch gobs of these into a new aerated wort (has O2 again), you would probably get a slower start on your fermentation since the petites can't use the O2.

Obviously, people have been re-using strains though, so there are ways around this - I'm just not sure what the tricks are. The Palmer book mentioned something about trying to get the yeast from the middle of the cake - maybe this enriches for the normal yeasties.

The other problem I've seen mentioned is stress from high alcohol content, but I don't really get what the problem is for the actual survivors.

 

[brewit2it]

From what I've read the potential problem is that putting the yeast through a round of fermentation can change them so that what you are using the 2nd go-round isn't really identical to what you were using the first time.

So far I've only thought of one specific example of what could be happening and they are called "petite" mutants. It goes something like this: you pitch healthy new yeast into a batch and they take off quickly because they can use O2 that is in the wort that lets them grow faster. (this is why we go through the trouble of aerating our wort before pitching the yeast)

The O2 gets depleted quickly as the yeast proliferate, and the bulk of fermentation kicks in. However, the absence of O2 allows a specific type of mutant, called a "petite" mutant, to flourish. Petite yeast have lost the ability to use O2. Normally this is tough luck for the poor sickly petite mutant, but its not a big deal in your fermenter since there isn't any O2 around anyway so the petites probably work just fine during fermentation. Come the end of fermentation, our yeast cakes probably have quite a few of these petites in it. So, if you pitch gobs of these into a new aerated wort (has O2 again), you would probably get a slower start on your fermentation since the petites can't use the O2.

Obviously, people have been re-using strains though, so there are ways around this - I'm just not sure what the tricks are. The Palmer book mentioned something about trying to get the yeast from the middle of the cake - maybe this enriches for the normal yeasties.

The other problem I've seen mentioned is stress from high alcohol content, but I don't really get what the problem is for the actual survivors.

Again, nice in theory but personal experience tells me the beer come out fine as long as you aerate and ferment cool. I have no intention of stopping the practice because I like the beer it makes and it saves me one time from having to do the worst task in home brewing, cleaning my 7.5 gallon carboy.

Basically the only real downside of over-pitching is reduced ester production (which is a good thing to me for pretty much everything I make) and possibly getting some extra hop/grassy flavor from the leftover hops in the first batch, but again I'm going from less hops to more hops so have never found a problem with that.

 

[cheezydemon3]

WHAT I DO WHEN LAZY OR NOT!!!

Is to pour out most of the cake with tap water (mine is evidently fine) and leave a good cup or so.

Pitch the wort on that.

 

[brewit2it]

WHAT I DO WHEN LAZY OR NOT!!!

Is to pour out most of the cake with tap water (mine is evidently fine) and leave a good cup or so.

Pitch the wort on that.

Yeah, I do that sometimes too, not the tap water but just pour a lot of it out. But I can't say I can tell a difference except that I have a smaller cake than when I pitch on the whole thing.

 

[YeastHerder]

How many times do you repeat the cycle of reusing yeast from a cake before going back to store-bought yeast? One repeat, two, too many to count?

 

[iambeer]

I heard about 4 or 5. Personally, I'm into the idea of propogating the first gen into about 6 slants and then getting a solid six months out of them. Why risk your wort? It's not the cash spent on grain and hops, it's the pride you may get from a decent wort you took the time to make... nothing can stop you now but fresh yeast (and good cleaning practice).

Fresh, healthy yeast is a service provided by grade A companies that most hobbies don't see in terms of level of dedication and quality. Well worth supporting.