Yeast Harvesting - Is This Method Viable?

[Hogan]

I have done some trials on harvesting yeast form the fermenter but have found that washing the yeast more than once provides only a minuscule amount to work with. I have found that at the end of cold conditioning my beer after primary fermentation there is about a half cup of sludge left on the bottom of the CC vessel (cube) which when left in the fridge for ten minutes produces what appears to be a good deal of yeast.

So that there is no confusion with the cold conditioning process actually being mistaken for secondary fermentation I have listed the steps taken to reach the half cup of sludge stage.

1. Primary fermentation carried through to final gravity.

2. Beer is racked off yeast cake into a cube. Cake, trub & heavy sludge are left behind.

3. Cube goes direct into cold conditioning at 0c.

4. After four days of CC, polyclar added.

5. Beer racked through filter into keg.

6. Sludge left in bottom is swirled and mixed with small amount of beer remaining in cube.

7. Sludge placed in jar in fridge and allowed to separate.

8. Large amount of what appears to be viable yeast drops to bottom of jar.


It is undisputed that the beer racked from the primary fermenter still contains viable yeast. When transferred to the cube that yeast will go to sleep due to the CCing but sufficient will still remain in suspension and later (if bottling) will travel through the filter to carbonate the beer.

It should be stressed that this process does not include a secondary fermentation stage. Lagers remain in primary for a full two weeks, ales less. Final gravity has been reached in primary and ccing will not allow any additional fermentation.

I think that the half cup of sludge left after ccing is mostly yeast and when harvested and awoken would produce a far greater quantity than what could be washed from the primary fermenter sludge.

I intend to make up a trial starter using this yeast and see what transpires.

What do those experienced with yeast harvesting think?


Cheers, Hoges.

 

[Fatgodzilla]

What do those experienced with yeast harvesting think?

Cheers, Hoges.

Whilst far from an expert, I use the "seconds" trub often as the yeast for another brew. I too like going "full term" in my fermenter but like to put all brews into cubes and the fridge for a second period - whether ale or lager. This way the beer is cold before kegging. (or else I don't have time to bottle). But under the principle, an empty fermenter is a waste, I've often poured the "trub" from the secondary conditioner onto the new brew with excellent results. I don't know how much of this trub is viable yeast and what part of it isn't, as I keep getting conflicting stories about what the yeast is, all I know is it works fine.

I don't harvest and clean yeasts (love playing with different yeasts) but have re-used a Wyeast American Ale II yeast over the past six months in three brews without a failure (so original brewed last October, then re-used the secondary trub each time in three consecutive brews). Just out of cube into new wort.

 

[JasonY]

I am sure it will produce a viable starter and I have done the same thing a number of times. I can't say I am an expert but the potential drawback could be that you are inherently collecting yeast with a low flocculation by gathering stuff from the secondary (given they didn't settle in the primary). Probably a strain dependent kind of thing but worth considering. I usually harvest from primary if I am going to as I figure it is a fresh as its going to get but just needs a clean.

Don't think you will have any problems.

 

[Hogan]

the potential drawback could be that you are inherently collecting yeast with a low flocculation by gathering stuff from the secondary (given they didn't settle in the primary).

Don't know that this is the case regarding low floculation - but I would think that yeast that is still in suspension in the primary and therefore still working and is then racked into the cc cube - would be more viable than yeast that has finished its job and has sunk to the bottom. Or is it the other way around.

Just to clarify - This is not 'secondary fermentation' as the fermentation has been stopped at 0c. I am aware that yeast harvested at the end of secondary is not considered very viable but my method is not utilising secondary - It's primary then straight into CC.

I am intending to keep the yeast for future brewing (months) not just putting another brew straight on top of the sludge.

Cheers, Hoges.

 

[damoncouper]

I think that you are onto something, very little handling and therefore a lower chance of infection. Only catch I can see is that the jar could be a little bulky if you are storing quite a few in the fridge when compared to slant vials. Does any one know if these would store as well as agar slants?

 

[Hogan]

I think that you are onto something, very little handling and therefore a lower chance of infection. Only catch I can see is that the jar could be a little bulky if you are storing quite a few in the fridge when compared to slant vials. Does any one know if these would store as well as agar slants?

I'd be using a syringe to suck out the yeast from the jar and inserting it into empty Whitelabs vials.

Cheers, Hoges.

 

[Stuster]

I don't think that the yeast in the secondary is more viable than the yeast in the secondary. That the yeast has flocculated to the bottom is not a sign of poor health or a lack of viability. The yeast you collect from the secondary is the least flocculant yeast as Jason said. Whether you want that less flocculant yeast is really up to you. I'm not sure it'd make a huge difference for one or two generations anyway, but if you keep doing this, you may end up with very dusty yeast.

I can't really see why you are having difficulty collecting yeast from the primary though. There should be plenty of very fresh, very healthy yeast in there. If you only end up with a minuscule amount after washing it then it sounds like you're not doing it right. What's your procedure and how much yeast do you end up with? :unsure:

 

[the_fuzz]

6. Sludge left in bottom is swirled and mixed with small amount of beer remaining in cube.

7. Sludge placed in jar in fridge and allowed to separate.

8. Large amount of what appears to be viable yeast drops to bottom of jar.

In regards to the above, don't you want the liquid off the top, not the "sludge" that has fallen to the bottom?

 

[Hogan]

I don't think that the yeast in the secondary is more viable than the yeast in the secondary.

Not sure that I understand that Stuster. But I think I get your drift.



That the yeast has flocculated to the bottom is not a sign of poor health or a lack of viability. The yeast you collect from the secondary is the least flocculant yeast as Jason said. Whether you want that less flocculant yeast is really up to you.

Thought I had explained in my post that this method is NOT using yeast taken from secondary. There is no secondary process in this fermentation. Secondary fermentation is what the name suggests, additional fermentation undertaken in a second vessel whereby the wort is still fermenting at the same temperature as in the primary. Placing the beer into cold conditioning from the primary fermenter AFTER it has reached FG is not secondary fermentation. What I feel I am doing is allowing the yeast to drop to the bottom of the cc vessel and not mix with the gunk that is left behind in the primary.



I'm not sure it'd make a huge difference for one or two generations anyway, but if you keep doing this, you may end up with very dusty yeast.

My intention is to make up and use only the three phials of yeast from the ferment. I'm not planning of using this method time after time, generation after generation from the original. Just looking for a way to stretch my liquid yeast into four brews.




I can't really see why you are having difficulty collecting yeast from the primary though. There should be plenty of very fresh, very healthy yeast in there. If you only end up with a minuscule amount after washing it then it sounds like you're not doing it right. What's your procedure and how much yeast do you end up with? :unsure:

Washing the cake in the primary just once gives about 10ml of product in the bottom of a tube. Whether this is all yeast or yeast plus additional muck - I don't know. Additional washing gives about 2ml of product which I assume is pure yeast. I do feel that what remains in the bottom of the cube after cc'ing (not secondary fermentation) is most likely 99% yeast.

Thanks for the input fellas:


Cheers, Hoges.

 

[Hogan]

In regards to the above, don't you want the liquid off the top, not the "sludge" that has fallen to the bottom?

That is the case with washing from the primary but in this case I am suggesting that what is left in the bottom after racking and cc'ing is all, or nearly all, yeast.


Cheers, Hoges.

 

[Duff]

You said though that you add polyclar to the cube.

Can you differentiate between that and the yeast? Even though you filter I'd imagine that there would be polyclar still in the base of the cube.

 

[Stuster]

Not sure that I understand that Stuster. But I think I get your drift.

I mean that primary yeast is fresher so it should actually be more viable.

Thought I had explained in my post that this method is NOT using yeast taken from secondary. There is no secondary process in this fermentation. Secondary fermentation is what the name suggests, additional fermentation undertaken in a second vessel whereby the wort is still fermenting at the same temperature as in the primary. Placing the beer into cold conditioning from the primary fermenter AFTER it has reached FG is not secondary fermentation. What I feel I am doing is allowing the yeast to drop to the bottom of the cc vessel and not mix with the gunk that is left behind in the primary.

Secondary fermentation is really a misnomer. You shouldn't transfer to a second vessel until fermentation is completed IMO. So we are talking about the same thing, the second vessel. The yeast in this second vessel (a cube in this case) will not have flocculated in the first vessel. It might be less flocculant in later generations.

Washing the cake in the primary just once gives about 10ml of product in the bottom of a tube. Whether this is all yeast or yeast plus additional muck - I don't know. Additional washing gives about 2ml of product which I assume is pure yeast. I do feel that what remains in the bottom of the cube after cc'ing (not secondary fermentation) is most likely 99% yeast.

I'm not sure how you're washing it then. I get nearly more than a litre of yeast at the bottom of primary. After washing you should have a lot more than 10mls of yeast from that. I'm not sure if you've read Chiller's post on this, but I'm pretty sure he's looking at washing it twice and ending up with something like 3 vials of 50-100mls plus enough for another brew (with a starter). If you haven't read it, the post is here.

 

[chovain]

Thought I had explained in my post that this method is NOT using yeast taken from secondary. There is no secondary process in this fermentation. Secondary fermentation is what the name suggests, additional fermentation undertaken in a second vessel whereby the wort is still fermenting at the same temperature as in the primary. Placing the beer into cold conditioning from the primary fermenter AFTER it has reached FG is not secondary fermentation. What I feel I am doing is allowing the yeast to drop to the bottom of the cc vessel and not mix with the gunk that is left behind in the primary.

This is just a terminology thing. When most people talk about secondary fermentation, they're actually referring to conditioning in a fermenter (be it cold or otherwise). While the yeast is not fermenting much, it *is* still technically fermenting (It'll continue fermenting for months - just not very much). Regardless of the terminology, or whether the yeast is actually still fermenting, the point still stands: If you take your yeast out late, you are selecting cells that are less floculative. The cells that are suspended at the beginning of cold conditioning are those with a genetic predisposition to remain suspended. The more flocculative cells have already dropped out. Likewise, if you were to extract yeast from the trub too early, you'd end up with more flocculative cells.

Washing the cake in the primary just once gives about 10ml of product in the bottom of a tube. Whether this is all yeast or yeast plus additional muck - I don't know. Additional washing gives about 2ml of product which I assume is pure yeast. I do feel that what remains in the bottom of the cube after cc'ing (not secondary fermentation) is most likely 99% yeast.

Admittedly, I've never actually washed yeast myself, but I've seen a number of posts where people were accidentally washing the wrong thing. The numbers you're talking about there sound like you're doing something wrong.

To demonstrate the bit that you want, rouse the yeast bed and put it in a jar in the fridge, it will settle into layers over a couple of hours. It's the pale layer near the top that you're after. There should be a really clear line between grey trub and the white yeast.

It's not clear from your description that your doing each wash as a two step process (although after CC it's probably not so important). Just to confirm, each wash is two steps:
* let the liquid settle for a bit, then throw out the grey trub while keeping the milky (assuming you're washing with water, not beer) liquid.
* let it finish settling, and keep the white yeast solids, throwing out the relatively clear (same assumption) liquid.

If the solids you're thowing out in step one have started stratifying, then you have settled too much: there's probably good yeast in there, so you should start again. If the solids you keep in the second step are stratified, then you've got all the yeast you can, but still have some some trub. Depending on how much trub you've got in there, you can keep washing until you have a more pure sample.

You don't say how much of the bed you take, but if you're only getting 2mL of yeast out 0.5-1L of bed, then you're doing something wrong.

 

[Hogan]

You said though that you add polyclar to the cube.

Can you differentiate between that and the yeast? Even though you filter I'd imagine that there would be polyclar still in the base of the cube.

I cannot be certain that there is, or is not, residue of polyclar in the bottom Duff. It's job is to wrap around the heavy particles and drop them to the bottom so I would assume that there is a combination of the two.

Cheers, Hoges.

 

[Hogan]

This is just a terminology thing. When most people talk about secondary fermentation, they're actually referring to conditioning in a fermenter (be it cold or otherwise). While the yeast is not fermenting much, it *is* still technically fermenting (It'll continue fermenting for months - just not very much). Regardless of the terminology, or whether the yeast is actually still fermenting, the point still stands: If you take your yeast out late, you are selecting cells that are less floculative. The cells that are suspended at the beginning of cold conditioning are those with a genetic predisposition to remain suspended. The more flocculative cells have already dropped out. Likewise, if you were to extract yeast from the trub too early, you'd end up with more flocculative cells.

So Mark - are we after more flocculative cells or less flocculative. After all is not the product of yeast washing those cells that have fallen out in primary.

Are cells in suspension bad or good? Suspended cells going from cc into the bottle are what carbonates it.

If the cells in the cc cube have a predisposition to remain suspended and they came from the primary - what is in the slurry on the bottom of the cube?

edit: clarity

Cheers, Hoges.

 

[Hogan]

Found this article on Flocculation which shows that the yeast that has flocculated and dropped in the primary is superior to that which passes into the cc vessel and then drops. I am appreciative of the comments on my proposed method, which now seems a waste of time, and I would do better perfecting washing of the primary trub.

Thanks to those who have provided advice and guidance.


Cheers, Hoges.

 

[Stuster]

No probs, Hogan. Have a read of Chiller's post at the top of the Common Ground. I often don't bother washing at all and have not noticed any difference between when I do wash. If I've dry hopped in the primary, I do wash the yeast, but that's about it. (I am careful to get clear wort from the kettle though, and there's almost no hop trub or hot break coming from there.)

 

[Hogan]

No probs, Hogan. Have a read of Chiller's post at the top of the Common Ground. I often don't bother washing at all and have not noticed any difference between when I do wash.

Stuster - I actually used Chillers post as a trial run but it seems that he was going from jar A to jar B and back again a lot. I probably would not need to be so pedantic but as you know when you start off on a new slant you are sure that everything will go wrong when actually you get better results when you punt high and follow through. The desire to keep the phial viable for a few months is probably what concerned me about proper washing technique. Anyway I'll look more closely at Chillers post and the comments that flowed from it and see what results. Thanks for your help.

Cheers, Hoges.

 

[chovain]

Are cells in suspension bad or good?

There's actually no universal answer to that question. In general, you want your yeast to flocculate well, but you also want it to have time to finish the job. If you racked and propagated yeast within a day of fermentation starting, then you'd likely end up without much yeast in your finished beer, but it probably wouldn't attenuate well.

If you're brewing a Hefeweizen or an Australian Pale, you don't want all your yeast to flocculate. You're relying on keeping a few of the buggers around to help cloudy your beer up (along with other things).

Suspended cells going from cc into the bottle are what carbonates it.

Absolutely, but you really don't need a huge number of cells to prime your bottles. Like our genetic predisposition for height, it's only a predisposition. Get a million people with tall genes, and a few are going to turn out short for various reasons. Furthermore, once your tall people start reproducing, they're going to start passing on dormant short genes, so you're going to get more variety in height in the population.

It's the same for yeast. Even the most flocculative yeasts will reproduce and provide enough cells to carbonate your beer (it might just take them a bit longer to do it).

If the cells in the cc cube have a predisposition to remain suspended and they came from the primary - what is in the slurry on the bottom of the cube?

Again, it's only a predisposition. It's probably mainly yeast in the sediment, with some polyclar and miscellaneous organics thrown in. There certainly would be a decent proportion of viable yeast in there, but it might not be the most desirable yeast for you, and most importantly, if there's something wrong with your washing technique, you may be throwing the best of it away.

 

[Hogan]

Thanks Mark for answering my questions with clarity. I did see from that Flocculation article above that there was a link showing that the cells in suspension related to 'maturity' of the beer, so as you say whether you are a flocculator or a suspender, you have a different role to play in the process. Thanks for your help.


Cheers, Hoges.