Can Yeast Last Forever?

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Antler

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Im wondering if you had the space and supplies to do this, could you make a single vial last forever?

Say I took a single vial of WL001 and made a starter for a 5g batch. Then I pitch that into a 5g 1.030 starter. Harvest all that yeast and separate into vials. This should last for plenty of batches, but when I start to run out can I simply make step it up and make another 5g starter to start over again? Can I do this over and over without the yeast mutating?
 
Yeast will mutate over time. This is discussed in "Brew Like a Monk" as some of the breweries have been around for centuries. It's also discussed in "The Practical Brewer" and a number of other sources. It really depends on the strain and how it is propagated, but if you are careful about things 30-50 generations seems to be what I have read most commonly. In that time the yeast will preform in a very similar way, but if you maped out the entire DNA squence you would likely see small differences from one propogation to the next.
 
The anchor brewing guys on the the BN's Sunday session said they have been using the same yeast since they started brewing anchor steam which was many many years ago, but I'm sure their yeast storage practices are a ton better than a homebrewers without lab grade equipment.
 
Mutation will occur over time. But that is not necessarily a bad thing - you could end up with something good (or bad) - a unique house style - that will reflect what you have done to it. Quite an exciting prospect actually. I am planning on doing the same myself. I keep three strains on-hand but replace after a four generations max (Gen 1 in my interpretation being the first three or four bottles I can scoop out of the primary - technically Gen 2. Each of those would go on to provide three or four bottles of babies). I am now planning to keep one type going and going just to see what happens.
 
Yes, yeast mutates over time. If you're a homebrewer and you take a "divide and conquer" approach, it would take you quite a bit of time to get a noticeable flavor profile in your beer, especially if you brew similar beers back to back (similar OG + IBU) and ferment at the same temperature.

I take that divide & conquer approach in my write-up here. (shameless plug)

MC
 
Im wondering if you had the space and supplies to do this, could you make a single vial last forever?

Say I took a single vial of WL001 and made a starter for a 5g batch. Then I pitch that into a 5g 1.030 starter. Harvest all that yeast and separate into vials. This should last for plenty of batches, but when I start to run out can I simply make step it up and make another 5g starter to start over again? Can I do this over and over without the yeast mutating?

They yeast are always mutating. You start with 125-200 billion and end up with trillions of yeast at the end of fermentation. In that amount of replication, errors will occur even though there's built in error checking on part of the yeast. Some of the mutations will yield dum dum yeast that might die, some will be minor changes that have no bearing on the yeast's performance.
 
I plan to buy a stirplate and some flasks soon. If I can make a huge starter and split it into vials like that, you could really make the original vial go a long way!

I drink mostly ales, so right now I'm using a few different yeast strains, but plan to narrow down to 1 or 2 I can brew most of my beers with.
 
I plan to buy a stirplate and some flasks soon. If I can make a huge starter and split it into vials like that, you could really make the original vial go a long way!

I drink mostly ales, so right now I'm using a few different yeast strains, but plan to narrow down to 1 or 2 I can brew most of my beers with.

Look into Yeast Slants. There is a sticky on here about it.

They are easy to do with a minimal investment (~$50).

I've been using the same packet of Rogue PacMan for almost 2 years. I've built up a collection of other yeast as well. The start-up process is a little more time consuming than a normal starter, but it's not too bad.
 
This is a great discussion. I've wondered why we throw a ton of yeast down the drain and then spend $7 per batch on new yeast. It would be great if someone wrote up a clear step-by-step on salvaging yeast from a fermenter or bottles, then growing it, storing it, and reusing it.
 
Thanks for all the info! I'm going to look into the slants.

Another question. Ill likely harvest and re-pitch from the fermenter for 5-6 generations, then toss and grab one of the original vials to start over. Since I'd be using a clean (no hop/grain trub) vial from the original starter to replenish the yeast bank, will this make a difference to how the yeast will adapt/mutate compared to simply washing/re-pitching from the fermenter for 10+ batches?

How would you expect the flavour profiles to change in the finished product?
 
Since I'd be using a clean (no hop/grain trub) vial from the original starter to replenish the yeast bank, will this make a difference to how the yeast will adapt/mutate compared to simply washing/re-pitching from the fermenter for 10+ batches?

How would you expect the flavor profiles to change in the finished product?
The nicer you are to the yeast, the less it will mutate. By nice I mean close to 9°P wort, Fixed temperature between 60 and 80°F culturing temperature, and no hops.

The most common traits lost by mutation are
1) the ability to ferment maltose,
2) the ability to reproduce
3) the ability to flocculate
4) the ability to produce esters and other characteristic flavors
 
WoodlandBrew said:
The nicer you are to the yeast, the less it will mutate. By nice I mean close to 9°P wort, Fixed temperature between 60 and 80°F culturing temperature, and no hops.

The most common traits lost by mutation are
1) the ability to ferment maltose,
2) the ability to reproduce
3) the ability to flocculate
4) the ability to produce esters and other characteristic flavors

Thanks! I should have no problem with those guidelines. I looked into slants, but don't really want to go through that trouble. I'll just make a starter batch to fill 5-6 50ml vials. Each vial I'll use to build a starter, harvest for 5-6 generations and start over with one of the fresh vials. When I get down to the last vial, I'll do another starter to rebuild the bank. Should be fine for my small scale needs I'd think?
 
This is a great discussion. I've wondered why we throw a ton of yeast down the drain and then spend $7 per batch on new yeast. It would be great if someone wrote up a clear step-by-step on salvaging yeast from a fermenter or bottles, then growing it, storing it, and reusing it.

The easiest way to use yeast more than once is to dump the next batch of cooled wort onto the lees of a just finished brew. You just have to coordinate your kegging/bottling with brewing and do as much as you can in the way of not letting anything jump in. I use a drum tap and tube off my primary, so only the airlock is removed (while draining) until I am ready with the next batch. (Taste the outgoing beer just to make sure that it is not off in any way.) I use hop straining bags and grain strining bags when brewing, so I dont have much gunk other than yeast slurry at the bottom of my primary. I successfuly make three batches of ale on the one vial of yeast.

Now, to push the envelope and save yeast for use another time instead of back to back, I sanitize four beer bottles, bottle caps, a funnel and a measuring cup. Now at the end of kegging, I remove the lid, carefully scoop out four yeast dense scoops and fill the bottles (actually only about 3/4 full). Caps on and into the fridge. I lable them and give them a generation number. I don't plan on using any type more than four generations in my keeping (five in total). To revive: bring a bottle to room temp, (the yeast will have formed a cake on the bottom) prepare a starter flask, sanitize the bottle top areas with vodka, then uncap, sanitize again with a butane flame, pour a little of the beer off the top and taste to see if it's nasty, then if good, innoculate the starter. Ready to go in a few days. I have brought back WLP005 007 and 002 - nearly two years later!

Before pitching into a new brew, having sanitized the lip of the start flask, I do pour a small amout for tasting (again). Yeast slurry does not taste particularly good, but with some experience, you will have a clear sense of whether something really bad has gone wrong.

In this way you can make one vial go: 1:4:16:64:256. That's a lot of brewing and my fridge is not that big. Plus I like to keep three or four strains handy. So what I actually do is just keep four bottles of each in stock replacing as needed. When I hit re-use level four, I buy fresh. Four is just a number. I've seen ten and even 30 bandied around.

All of my regular beers are variations on pale ales. I would not suggest trying radically different styles from batch to batch as the yeast might mutate and rebel.

Together with homegrown hops and buying DME in bulk, my brewing is about as cheap as extract brewing gets. Give it a go. I was nervous to try at first but, so long as you keep a careful eye on sanitation, it's easy and saves a ton of cash.
 
EDS2K said:
The easiest way to use yeast more than once is to dump the next batch of cooled wort onto the lees of a just finished brew. You just have to coordinate your kegging/bottling with brewing and do as much as you can in the way of not letting anything jump in. I use a drum tap and tube off my primary, so only the airlock is removed (while draining) until I am ready with the next batch. (Taste the outgoing beer just to make sure that it is not off in any way.) I use hop straining bags and grain strining bags when brewing, so I dont have much gunk other than yeast slurry at the bottom of my primary. I successfuly make three batches of ale on the one vial of yeast.

Now, to push the envelope and save yeast for use another time instead of back to back, I sanitize four beer bottles, bottle caps, a funnel and a measuring cup. Now at the end of kegging, I remove the lid, carefully scoop out four yeast dense scoops and fill the bottles (actually only about 3/4 full). Caps on and into the fridge. I lable them and give them a generation number. I don't plan on using any type more than four generations in my keeping (five in total). To revive: bring a bottle to room temp, (the yeast will have formed a cake on the bottom) prepare a starter flask, sanitize the bottle top areas with vodka, then uncap, sanitize again with a butane flame, pour a little of the beer off the top and taste to see if it's nasty, then if good, innoculate the starter. Ready to go in a few days. I have brought back WLP005 007 and 002 - nearly two years later!

Before pitching into a new brew, having sanitized the lip of the start flask, I do pour a small amout for tasting (again). Yeast slurry does not taste particularly good, but with some experience, you will have a clear sense of whether something really bad has gone wrong.

In this way you can make one vial go: 1:4:16:64:256. That's a lot of brewing and my fridge is not that big. Plus I like to keep three or four strains handy. So what I actually do is just keep four bottles of each in stock replacing as needed. When I hit re-use level four, I buy fresh. Four is just a number. I've seen ten and even 30 bandied around.

All of my regular beers are variations on pale ales. I would not suggest trying radically different styles from batch to batch as the yeast might mutate and rebel.

Together with homegrown hops and buying DME in bulk, my brewing is about as cheap as extract brewing gets. Give it a go. I was nervous to try at first but, so long as you keep a careful eye on sanitation, it's easy and saves a ton of cash.

By just racking fresh brewed wort onto a yeast cake your greatly over pitching by roughly 3x. After the 3rd time you would be over pitching by a huge amount! I have no idea really but people say its just bad as under pitching lol
 
By just racking fresh brewed wort onto a yeast cake your greatly over pitching by roughly 3x. After the 3rd time you would be over pitching by a huge amount! I have no idea really but people say its just bad as under pitching lol
Yes, If you pitched on the entire yeast cake it would be over pitching in most cases. If you do want to pitch on top of the cake then remove all but 1/3 to 1/5 for equal gravity beers.

EDS2K didn't mention how much of the cake he uses, but everything he did say seemed spot on to me.

Here is some information about the effects of over and under pitching from Wyeast:

A low pitch rate can lead to:

Excess levels of diacetyl
Increase in higher/fusel alcohol formation
Increase in ester formation
Increase in volatile sulfur compounds
High terminal gravities
Stuck fermentations
Increased risk of infection

High pitch rates can lead to:

Very low ester production
Very fast fermentations
Thin or lacking body/mouthfeel
Autolysis (Yeasty flavors due to lysing of cells)
http://www.wyeastlab.com/hb_pitchrates.cfm
 
When you repitch yeast you're not just repitching your yeast colonies, you're also repitching the traces of bacteria that inevitably have "contaminated" your sample. This is one of the main problems I've heard of when repitching over many generations without lab-style equipment. Even many breweries that constantly reuse the same strain have to send their yeast to a laboratory to have it washed of other micro-organisms. As said above, with proper sterilization you can certainly reuse your yeast quite a bit (10 times is the guideline I've read most frequently). And, if you're not averse to potentially adding other fermentation products, bacteria may not pose a huge problem to you.

In a nutshell just remember that yeast are not the only microorganisms in your culture.
 
Good points. I'm testing yeast for free right now, and also working on an acid washing technique designed for home brewers. It utilizes items that almost everyone has, and if you don't, can get at just about any grocery store. It also doesn't require any special equipment like a microscope or a pH meter.
 
Clarification. When pitching on the yeast cake, my personal max is twice in a row (three total batches).

I don't get too excited about under or over pitching. You can drive yourself insane trying to measure and analyze everything.

Most of the time I brew variations on a pale ale / bitter theme (5 – 6lb DME, plus adjunct grains and hops from a choice of six types overflowing my freezer). This type of beer is very forgiving and unfussy. Heck, when I first started in this hobby you got barely a teaspoon of dried mystery yeast and had to use 2kg of white sugar to boost a pre-hopped kit. Look what we have available now!

Hence my system:

Batch 1, New WL vial no starter
Batch 2, pitch onto resulting yeast cake (or save one to four half-cup scoops, one scoop per bottle)
Batch 3 (if there was a Batch 2), pitch onto resulting yeast cake
Batch 4 (or 3 if there was no Batch 2), use a new fresh WL vial, or a 1L starter made from one of the stored bottles

The first saved bottles I label and number 1 (actually its second use of course). If I then use one of those bottles and choose to save yet more from after its use, I number those 2. I have set a personal limit of four generations, which is just an arbitrary number, but will certainly be safe from any weird mutations.

Works for me and the ultimate test is what did it taste like? The answer so far... Beer. Pretty darned good beer.
 
Watched a show on Anhueser-Busch. they are using the original yeast strain that they started with. Using one vial from a cryogenic yeast bank (about the size of a whitelabs vial) they step up the starter enough to turn that one vial to enough to ferment their massive batches, which I don't know how big their fermenters are but their lagering vessels are 133,000 BBL. But they can probably reuse yeast more than 10 generations since their OG is probably that of a typical starter anyways lol
 
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