Harvesting yeast

[InspectorJon]

I’ve read many times that it is better to harvest yeast from lower gravity beer because the yeast is less stressed so you get better yeast in the end. My thinking cap says that after the yeast from higher gravity beer has been stepped up a couple times in a good starter it is pretty much all new yeast and should be just as healthy as yeast from lower lower gravity beer. Am I wrong?

 

[Dgallo]

I’ve read many times that it is better to harvest yeast from lower gravity beer because the yeast is less stressed so you get better yeast in the end. My thinking cap says that after the yeast from higher gravity beer has been stepped up a couple times in a good starter it is pretty much all new yeast and should be just as healthy as yeast from lower lower gravity beer. Am I wrong?

Wrong because of what actually happens when you don’t have the equipment to properly clean yeast and separate good cells from bad cells. Each generation of yeast has a slight variation from the “mother” and actually becomes less likely to attenuate and provide the desired ester profile the more generations you go. Many commercial breweries won’t go past 8-10 generations with the same yeast.

You can certainly do what you are talking about and it will work for hopefully a few beers but you don’t know which generation it will be before it craps out on you.

Since you don’t have a lab at the house, I would suggest buying a fresh pack of yeast and over build the starter. That way you’ll grow more fresh yeast and you can save the excess and continue to do this for a few generation. This gives you More control of how clean your yeast is.

 

[CascadesBrewer]

You are probably wrong...but I have harvested yeast from beers in the 1.070 range and I have not noticed a difference. I would probably dump the slurry from that 1.120 RIS though.

 

[rhys333]

I’ve read many times that it is better to harvest yeast from lower gravity beer because the yeast is less stressed so you get better yeast in the end. My thinking cap says that after the yeast from higher gravity beer has been stepped up a couple times in a good starter it is pretty much all new yeast and should be just as healthy as yeast from lower lower gravity beer. Am I wrong?

Mutations occur, but it takes numerous generations to make any appreciable difference, so for the handful of generations we homebrewers reuse yeast it probably doesn't make a difference. You can select for certain properties (like higher or lower attenuation), but it takes consistent and usually deliberate effort.

 

[InspectorJon]

Each generation of yeast has a slight variation from the “mother” and actually becomes less likely to attenuate and provide the desired ester profile the more generations you go. Many commercial breweries won’t go past 8-10 generations with the same yeast.

This seems to be related to numerous generations not high gravity.

Mutations occur, but it takes numerous generations to make any appreciable difference, so for the handful of generations we homebrewers reuse yeast it probably doesn't make a difference.

So I am not quite getting the logic behind these answers as relates to using yeast harvested from high gravity beer. I'm talking about 1.070 beer or something like that. But even with that Imperial Stout, if the cells are still alive and can reproduce why would the daughters be bad? (Don't ask about my children please.) Is the implication that higher gravity fermentations are more likely to lead to mutations?

 

[Vale71]

I’ve read many times that it is better to harvest yeast from lower gravity beer because the yeast is less stressed so you get better yeast in the end. My thinking cap says that after the yeast from higher gravity beer has been stepped up a couple times in a good starter it is pretty much all new yeast and should be just as healthy as yeast from lower lower gravity beer. Am I wrong?

You're probably not wrong, provided the harvested yeast has enough residual vitality to produce significant growth in the starter. However, the idea behind yeast harvesting is NOT to have to propagate the yeast since at the end of fermentation you have a lot more yeast than what you'd need for a second batch of the same size and gravity. Your idea of making a stepped starter kind of negates that advantage.

 

[Dgallo]

This seems to be related to numerous generations not high gravity.



So I am not quite getting the logic behind these answers as relates to using yeast harvested from high gravity beer. I'm talking about 1.070 beer or something like that. But even with that Imperial Stout, if the cells are still alive and can reproduce why would the daughters be bad? (Don't ask about my children please.) Is the implication that higher gravity fermentations are more likely to lead to mutations?

Stressed yeast are not healthy yeast. So if you’re using that yeast cake, they can be sluggish to take off, having trouble eating and multiplying. Like someone stated before,. You can’t know the viability, aka how many cells are healthy and alive after a fermentation. With higher gravity beers will typically have much less viability than a small beer. You keeping saying 1.070, but what did you finish at. You could range anywhere from like a 6.6 - 8% abv with that starting gravity which will have a difference in the viability.

To answer you question. Yeah you can certainly do what you are planning to do, just know there is a chance for the beer not to fully attenuate and throw off flavors. Will it happen for sure? No, but the chance is there.

 

[InspectorJon]

I think I did not make myself clear in my original question. I guess I mean to say high alcohol, not necessarily high gravity. My question is about harvesting yeast from a bottle or can from the store. Thus my discussion about stepping up a starter. Bell's yeast to be specific. Last time I mentioned the brand name it sparked a debate regarding that particular yeast and I don't care about that.

I am wondering why folks say a lower alcohol beer is better to harvest from. Lets not debate what kind of yeast it is. I'm not talking about harvesting yeast from a previous fermentation at home, although I have heard the high alcohol vs. low alcohol argument in that context also.

Let me restate the question. Why is it better to harvest yeast from a bottle of lower alcohol beer than a higher alcohol beer? Won't it all be new healthy yeast once it is stepped up in a healthy environment?

 

[kh54s10]

I think this partially depends on the yeast. If the ABV of the beer approaches the alcohol tolerance of the yeast you may have a lot of dead cells in your harvest and IMO, they will be stressed. So a lower alcohol beer would be better.

Another thing you don't know is what yeast it is. You might get one that conditions with their house yeast. Others use a bottling yeast that imparts little or no flavor to the beer. So you might have a mix of their house yeast and bottling yeast. One of those would probably dominate the other and you will not know which.

Some filter, centrifuge, or pasteurize the beer so there is no viable yeast then they artificially carbonate.

The only real way is to try and hope for the best. Others have done it and a search might tell you which beers they have had good success with.

 

[rhys333]

This seems to be related to numerous generations not high gravity.



So I am not quite getting the logic behind these answers as relates to using yeast harvested from high gravity beer. I'm talking about 1.070 beer or something like that. But even with that Imperial Stout, if the cells are still alive and can reproduce why would the daughters be bad? (Don't ask about my children please.) Is the implication that higher gravity fermentations are more likely to lead to mutations?

1.070 really isn't all that high a gravity, so I wouldn't worry about occasionally reusing yeast in those situations. Super high gravity beers can cause stress, and may even select for cells that are able to ferment at higher abv, potentially changing the strain characteristic over numerous generations. We're working with living organisms here, so they naturally adapt to whatever we throw at them.

 

[Dgallo]

I think I did not make myself clear in my original question. I guess I mean to say high alcohol, not necessarily high gravity. My question is about harvesting yeast from a bottle or can from the store. Thus my discussion about stepping up a starter. Bell's yeast to be specific. Last time I mentioned the brand name it sparked a debate regarding that particular yeast and I don't care about that.

I am wondering why folks say a lower alcohol beer is better to harvest from. Lets not debate what kind of yeast it is. I'm not talking about harvesting yeast from a previous fermentation at home, although I have heard the high alcohol vs. low alcohol argument in that context also.

Let me restate the question. Why is it better to harvest yeast from a bottle of lower alcohol beer than a higher alcohol beer? Won't it all be new healthy yeast once it is stepped up in a healthy environment?

Because alcohol environments are not ideal for yeast. They will die at high alcohol percentages than lower. That’s why rubbing alcohol gills 99.9 percent of germ. The lower the alcohol the greater the viability of the yeast, aka number of healthy cells.

 

[IslandLizard]

Let me add that yeasts can be selected for their ability to ferment higher alcohol beers. Some as high as 28% and above. Think Sam Adams' Utopias, and some of those BrewDog creations.

That selection process is complicated, takes time, patience, knowledge, and dexterity. But it comes down to careful cultivating and the last cell standing. Now those special cells aren't going to give you the sought after flavor profiles lesser tolerant cells do. So expect a complex mixture of different selected cultures and phenotypes being used concurrently. They all get their turn to shine, until their time is up.

Let's aim focus back on the very topic of reusing yeasts harvested from higher gravity brews. Guess which phenotypes you're selecting for and against? If it works in your favor for what you have in mind, by all means, go for it. And please keep us informed about your experiments and how they turn out. We're an always interested bunch here in this corner, who won't pass up anything novel.

 

[InspectorJon]

Well I am a creative adventurous individual with a minimal amount of funds to invest in this great hobby. I have a simple BIAB system worked out and using stuff I already had I don't think I have spent more than a hundred dollars on equipment yet. I have made some very good beer.

Yeast is expensive on a low budget and I would like to try something besides US-05 so I am thinking about bottle harvesting. My daughter brought me a 12 pack of Bell's Two Hearted ale (we don't get that where I live) and I have some yeast growing from that now. I was thinking of using it in the Yellow Rose clone here on HBT. There is a lot of discussion about Bell's house yeast in other parts of HBT and it has kind of been discouraged to use the Two Hearted ale to harvest from. I'm wondering if there is any science behind that or if it is just some of that traditional lore like "you should use a secondary fermenter to keep beer off dead yeast". I started brewing beer back in the 70s and that was the wisdom then.

I'll let you know how the Bell's yeast works in the Yellow Rose Mosaic/Pilsner SMASH.

 

[InspectorJon]

I started with dregs from two cans. Wiped the tops with isopropyl alcohol. First step was 8 oz of 1.020 wort. This is 16 oz of 1.035 wort. That white stuff at the bottom looks like yeast. What next?

 

[rhys333]

I started with dregs from two cans. Wiped the tops with isopropyl alcohol. First step was 8 oz of 1.020 wort. This is 16 oz of 1.035 wort. That white stuff at the bottom looks like yeast. What next?View attachment 621317

Leave it for a week or more to ensure its fermented (during the first couple steps the yeast can be weak), then cold crash in the fridge until it settles. Then pour off the beer and feed it with more 1.030-40 wort. If you have a viable product, this third step should show signs of activity quickly. Repeat the above steps and either pitch to a small 1-2 gallon batch or make a 1.5L starter and use the resulting yeast in a 5 gallon batch.

 

[InspectorJon]

Leave it for a week or more to ensure its fermented (during the first couple steps the yeast can be weak), then cold crash in the fridge until it settles. Then pour off the beer and feed it with more 1.030-40 wort. If you have a viable product, this third step should show signs of activity quickly. Repeat the above steps and either pitch to a small 1-2 gallon batch or make a 1.5L starter and use the resulting yeast in a 5 gallon batch.

The second step was bubbling in less than 12 hours so I’m hopeful. It smells clean.

 

[rhys333]

The second step was bubbling in less than 12 hours so I’m hopeful. It smells clean.

That's great. Depending how much yeast you have now, you may be able to skip a step and pitch what you have into a 1L or 1.5L starter. It sounds like it's strong enough to handle it.

 

[InspectorJon]

If I just poured my 16 oz jar of starter into a bottle with 1/4 cup starsan did I just kill it?

 

[IslandLizard]

If I just poured my 16 oz jar of starter into a bottle with 1/4 cup starsan did I just kill it?

I seriously doubt it.
RDWHAHB!

 

[kh54s10]

I would consider that as a typical package of liquid yeast. I always use a yeast calculator to determine how much yeast I need for the beer that I am brewing rather than just making a starter of X size. It may be smaller or it may be bigger in volume depending on the gravity of the wort it is going to go into.

 

[CascadesBrewer]

If I just poured my 16 oz jar of starter into a bottle with 1/4 cup starsan did I just kill it?

That would suck if it did after all this effort!

Yeast is expensive on a low budget and I would like to try something besides US-05 so I am thinking about bottle harvesting.

This is a cool effort to watch and the idea of harvesting yeast from a bottle of beer is interesting. I would say on the "yeast is expensive" topic, that is one of the reasons I harvest and reuse yeast. With the 15 or so batches I have done since December (mix of 5 gal, 2.5 gal, and 1 gal) I think I purchased 1 pack of S-04 and two packs of White Labs (also harvested some Wyeast Irish Ale from my GFs batch) . $8 for a pack of yeast for one batch is a little pricey...but a few reuses brings that price down to a buck or two a batch.

 

[IslandLizard]

If I just poured my 16 oz jar of starter into a bottle with 1/4 cup starsan did I just kill it?

Is that the yeast in the jar pictured above?

If so, that's likely not enough for a 5 gallon pitch, especially in a 1.060-1.070 wort. Use a yeast calculator.

You really should make a full size 2 liter starter with that, after first cold crashing what you have now, and decanting the clear supernatant. IOW, use the slurry for further propagation, not the (used) starter beer.

That way you can pitch + save some out for making a new, fresh, unused starter. And so on.

You can also repitch from a fermenter's yeast cake.

 

[rhys333]

Is that the yeast in the jar pictured above?

If so, that's likely not enough for a 5 gallon pitch, especially in a 1.060-1.070 wort. Use a yeast calculator.

You really should make a full size 2 liter starter with that, after first cold crashing what you have now, and decanting the clear supernatant. IOW, use the slurry for further propagation, not the (used) starter beer.

That way you can pitch + save some out for making a new, fresh, unused starter. And so on.

You can also repitch from a fermenter's yeast cake.

The OP harvested from a 1.070 beer but didn't specify pitching to a beer of the same gravity, unless I'm mistaken.

I find the yeast calculators are a good way to find a bearing, but they generally underestimate the viability or cells by a considerable margin. I prefer to estimate 1.5B cells/ml of fresh yeast (assuming 200B desired per 5 gallons), and I find even that is a cautious overestimate.

 

[InspectorJon]

Is that the yeast in the jar pictured above?

If so, that's likely not enough for a 5 gallon pitch, especially in a 1.060-1.070 wort. Use a yeast calculator.

You really should make a full size 2 liter starter with that, after first cold crashing what you have now, and decanting the clear supernatant. IOW, use the slurry for further propagation, not the (used) starter beer.

That way you can pitch + save some out for making a new, fresh, unused starter. And so on.

You can also repitch from a fermenter's yeast cake.

The yeast in the jar pictured is the second step. It is a 16 oz jar. I poured that into a sanitized 1 liter bottle with an airlock to let it finish until I get some more extract. I neglected to pour the Starsan back out of the one liter jar. There may have been up to 8 oz of Starsan in the 1 liter bottle when I transferred the 3 day old second step into it. It is cold crashing now and I will try to use what settles to make a bigger starter when I am ready to brew next. I am hoping there will still be enough viable yeast to make the starter after the Starsan incident.

 

[IslandLizard]

The yeast in the jar pictured is the second step. It is a 16 oz jar. I poured that into a sanitized 1 liter bottle with an airlock to let it finish until I get some more extract. I neglected to pour the Starsan back out of the one liter jar. There may have been up to 8 oz of Starsan in the 1 liter bottle when I transferred the 3 day old second step into it. It is cold crashing now and I will try to use what settles to make a bigger starter when I am ready to brew next. I am hoping there will still be enough viable yeast to make the starter after the Starsan incident.

It's probably fine. Acid won't necessarily kill yeast. True yeast washing uses a fairly strong acid, but it's done right before pitching into a batch. Breweries wash yeast to remove/kill any bacterial content.
After cold crashing and decanting the acidic Starsan/starter beer mixture off, making another starter is a very good idea. You need more yeast anyway.

When using a yeast calculator, such as HomebrewDad's, you'll see that a stir plate provides for much larger growth than an intermittent shaken jar. Stirring also removes CO2 build up, preventing sudden blow offs, which always seem to happen overnight. Build a stir plate.

 

[ESBrewer]

Let me restate the question. Why is it better to harvest yeast from a bottle of lower alcohol beer than a higher alcohol beer? Won't it all be new healthy yeast once it is stepped up in a healthy environment?

1) The high alcohol is detrimental for the strucure and functions of yeast cells and thus the high abv bottles tend to have less viable yeast cells.
2) High abv causes a stress response in yeast and even the viable cells may be less prepared to grow compared to same cells in low abv bottle. Thus, there may be a longer lag time starting with the material from high abv bottle. This will increase the chance that something else than brewing yeast will start growing in the culture. This is especially the case when the cell count is low as is usually the case when you start from bottle dregs.
3) High abv conditions tend to induce so called petite (respiratory deficient) mutants that lack part of mitochonrial DNA and have altered capability to harvest available energy resources. This type of mutations are one of the reasons why brewer's yeast can not be recycled forever (the character of the beer starts drifting away eventually). When you start from high abv bottles, the rate of petite mutants tends to be higher and it also tends to increase later (especially if you brew high abv). So by starting from low alcohol brew you get the freshest, highest quality material.
4) High abv will put selective pressure on yeast and the variants/mutants that grow readily under these conditons will be enriched, changing the nature of the population. This change may not always be the best in terms of taste & other fermentation characteristics.
5) High abv beers may have longer conditioning times, during which viable cell counts may decrease. Sometimes these beers also have higher IBUs and more hops, which may be suboptimal for yeast health (although high abv & high hops may also inhibit the growth of unwanted microbia).

That being said, if high abv beer is the only source that you have, you could use that. It will probably work (if there are viable cells) and there is a good chance that you will end up with most delicious beer. But in theory, low abv will yield a better quality yeast.

 

[InspectorJon]

1) The high alcohol is detrimental for the strucure and functions of yeast cells and thus the high abv bottles tend to have less viable yeast cells.
2) High abv causes a stress response in yeast and even the viable cells may be less prepared to grow compared to same cells in low abv bottle. Thus, there may be a longer lag time starting with the material from high abv bottle. This will increase the chance that something else than brewing yeast will start growing in the culture. This is especially the case when the cell count is low as is usually the case when you start from bottle dregs.
3) High abv conditions tend to induce so called petite (respiratory deficient) mutants that lack part of mitochonrial DNA and have altered capability to harvest available energy resources. This type of mutations are one of the reasons why brewer's yeast can not be recycled forever (the character of the beer starts drifting away eventually). When you start from high abv bottles, the rate of petite mutants tends to be higher and it also tends to increase later (especially if you brew high abv). So by starting from low alcohol brew you get the freshest, highest quality material.
4) High abv will put selective pressure on yeast and the variants/mutants that grow readily under these conditons will be enriched, changing the nature of the population. This change may not always be the best in terms of taste & other fermentation characteristics.
5) High abv beers may have longer conditioning times, during which viable cell counts may decrease. Sometimes these beers also have higher IBUs and more hops, which may be suboptimal for yeast health (although high abv & high hops may also inhibit the growth of unwanted microbia).

That being said, if high abv beer is the only source that you have, you could use that. It will probably work (if there are viable cells) and there is a good chance that you will end up with most delicious beer. But in theory, low abv will yield a better quality yeast.

Thank you for the detailed answer. This is the kind of information I was looking for. This is what is great about this community.

 

[InspectorJon]

Update on this experiment. I stepped the bottle harvested Bell's yeast up once more from a pint to to a 1 liter starter which took right off. It survived the Star San fine. After a couple days I pitched this into a 3.5 gallon batch of Yellow Rose Clone, except this is Bell's yeast and not Lone Pint's. Yellow Rose is a Mosaic/Pilsner SMASH. The Bell's yeast took the 1.068 wort down to 1.011 for 83% AA. The gravity sample tastes good so I guess I got some healthy yeast. I pitched 3/4 of the starter and kept the rest for a future starter. Cold crashing now. We will see in 3 weeks or so how this turns out after bottle conditioning.

 

[CascadesBrewer]

Nice! BTW, I did see somebody (Omega? Imperial?) was now selling Bell's house yeast. I am not sure if it is available for purchase yet or not.

 

[InspectorJon]

I'm calling it Yellow Bell. Yellow Rose clone with Bell's yeast. This is after 48 hours at ice water temperature. No kettle finings or gelatin. My bottle harvested Bell's yeast does not seem to flock real well. A couple smaller additions of boil hops and 40 grams Mosaic whirlpooled at 170 degrees. I also dry hopped it on day 3 of active fermentation with 40 grams of Mosaic. That is an old 5 gallon Alhambra water bottle with a little over 3 gallons of beer. Pilsner/Mosaic SMASH is looking kind of New Englandish.

 

[InspectorJon]

Verdict is in. This is awesome. Yellow Bell using Yellow Rose recipe with Bell's yeast. It should get better with a little more time bottle conditioning but it is outstanding now. Thanks for the encouragement and advice regarding yeast harvesting from cans.