Yeast lifespan?

[petrostar]

Simple question for the masses, maybe! I have been harvesting my yeast from my primary fermenters for the last 9 months. I've reused my cali ale yeast maybe 7-10 times. I do a starter every time. My question is why do I read about people suggesting you can or should use harvested yeast max four or five times? My starters are always active, my yeast always attenuate, my beer always finishes clear and off-flavor free. How long have you used a yeast harvest and why did you stop using it? I just pitched the same yeast again on another 10 gallon IIpa, and my imperial pumpkin.

 

[LVBen]

There is a very complex answer to what you are asking and a very simple one.

The simple answer is that people have had beers turn out badly after reusing yeast.

If you can get good results doing what you are doing, then you should keep doing it. I've also gotten good results when reusing WLP001.

If you want the complex answer, then maybe you'd be better off reading a book about yeast.

 

[Airborneguy]

I reuse yeast almost exclusively now. I just made a porter with a saved batch of 1028 that had been in a mason jar in my fridge since January. Fermented perfectly.

Unless the yeast is less than a month old, I always do a starter. So far, I've never used a single yeast more than 3 times, but I'm planning to get to at least 10 before I have to re-start the cultures in the future.

 

[Nashbrewer]

Random Mutation is why you limit the number of generations of yeast that you use from a single strain before starting fresh with a new packet from the lab. As the random mutations increase you can get a wide variety of things going wrong.
I asked people at Yazoo here in Nashville, and they said 10 generations is how long they reuse yeast before starting fresh.

 

[smokinghole]

The amount of times you repitch is very dependent on how you are collecting the yeast. Long story short is that mutations over time will affect fermentation characteristics and flocculation of the yeast. It can be for better or for worse. The final judge is if you like where your mutated strain is going if it does mutate on you. The breweries only go 10 pitches because the yeast can change. They want a consistent product and because of that they will order or grow up a new culture. If you are interested in seeing where your yeast can go by pitching 20-30 times you will not be in danger. As long as you think the beer tastes good you can keep going.

 

[petrostar]

Awesome information guys. How many times have you pitched?

 

[beowulf]

I've reused Wyeast 1968 ESB and Nottingham about 10 times each. I think just the last batch of each was an imperial, barleywine or something with a bunch of chocolate...can't remember. I do know that I had a number of 7-8% beers in the middle of the lineup, so it was not always a 5% pale ale feeding a bigger beer. As for ending the dynasty, I guess I just wanted to try a different yeast for the heck of it.

As an aside, I took the brewery tours at Avery and Great Divide, both of which said they reused yeast 10-15 times on average.

I'd definitely like to hear from someone who has actually experienced yeast mutation as a result of using it too many times. I hear folks talk about it all the time, but I don't recall hearing of anyone who actually had yeast mutate to the point they knew something was different or "off" about it.

I think I may conduct a study where I reuse a yeast as much as possible for my favorite style (IPA, duh) and see how long I can keep it going. I'll report back on that if possible. I'm going to culture some Bell's yeast for a Hopslam clone I'm planning, so maybe I'll make that my test case. Ohhh fun...a project

 

[kbuzz]

I reuse yeast until I get a unordinary fermentation.

For me, this usually happens around gen 7-10...and it probably has something to do with my yeast harvesting technique - I'm sure some people can make their strains last longer before puttering out...

As with everything else in this hobby, everything is specific to your own techinique. Once you determine how many generations your technique will allow, that's when you should cut off your harvesting...

 

[beowulf]

In fact, my Rye IPA was fermented with 1/2 cake of 5th-generation Notty yeast from an IIPA. Won Best of Show at the Nebraska State Fair this year. Those yeasties were eating their wheaties!! (well ya know, "rye-ies" just doesn't sound cool)

 

[petrostar]

In reply to my own question, 7 is maximum... Got my first bad batch, ten gallon imperial Ipa. Little bit pissed but you live and learn. It's drive. Kable but just has a really odd finish. Had a friend brew buddy try it. He said it tastes contaminated but the hops cover it up. Over all I'm not sure what to do with it. It tastes perfectly fine after you've had one. Lol

 

[Half-cocked]

I have always wondered... How do yeast companies consistently produce the same strains of yeast, year after year and generation after generation, in the face of the same forces (random mutations and/or strain 'weakening') that affect brewers? Is there a hidden "black art" to yeast production that's kept secret from mere mortals, to protect the yeast cartel's monopoly on yeast production?

 

[ajf]

Once every 6 months or so, I buy myself a vial of yeast. I make a starter with it, and pitch the starter into the fermenter. At the end of fermentation I keg the beer, and harvest and wash the yeast cake. This gives me enough yeast to do another 4 brews if I make a starter from the washed yeast.
Each of those 4 brews generates enough yeast for another 4 brews, so that's a total of 21 brews using one vial of yeast for 3 generations, or about 6 months supply using the one yeast. I also buy small amounts of other yeasts for different styles of beer that I don't brew so often, but I don't harvest them as extensively because that would take many years to work through 3 generations, and I don't know how long the washed yeast lasts.
I used to do more than 3 generations, but once I got a bad mutation after about 4 - 5 generations, so I now keep it down to 3 generations just to be safe. I've never had a problem with 3 generations.

-a.

 

[LVBen]

I have always wondered... How do yeast companies consistently produce the same strains of yeast, year after year and generation after generation, in the face of the same forces (random mutations and/or strain 'weakening') that affect brewers? Is there a hidden "black art" to yeast production that's kept secret from mere mortals, to protect the yeast cartel's monopoly on yeast production?

There are no hidden secrets. There is quite a bit of information around about yeast propagation and maintenance. They use liquid nitrogen to store yeast cells for years. They do extensive testing and analysis on the yeast cultures to make sure they have the correct characteristics by pulling out small amounts of yeast from an entire culture, re-propagating, and doing test batches.

http://www.maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

 

[cuttsjp]

Random Mutation is why you limit the number of generations of yeast that you use from a single strain before starting fresh with a new packet from the lab. As the random mutations increase you can get a wide variety of things going wrong.
I asked people at Yazoo here in Nashville, and they said 10 generations is how long they reuse yeast before starting fresh.

+1! I was just going to give the same answer and cite the same source! Love the people of Yazoo.

 

[smokinghole]

There are no hidden secrets. There is quite a bit of information around about yeast propagation and maintenance. They use liquid nitrogen to store yeast cells for years. They do extensive testing and analysis on the yeast cultures to make sure they have the correct characteristics by pulling out small amounts of yeast from an entire culture, re-propagating, and doing test batches.

http://www.maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

My school allowed me to do a cyrogenic prep on some strains. Now all I have to do is make up some malt extract plates dip an innoculating loop in the cryo tube and quickly streak. Then throw the box back in the -80C fridge before any thawing really occurs. Let the streaked culture grow for 4-5 days and pick the best looking colony then pull that with a sterile loop and innoculate a small amount of sterilized wort. Then grow from there to a pitching quantity.

It doesn't have to be liquid nitrogen, but that is the cheaper and colder method to do long term storage. Those -80C freezers are like $15,000.

 

[brettwasbtd]

Simple question for the masses, maybe! I have been harvesting my yeast from my primary fermenters for the last 9 months. I've reused my cali ale yeast maybe 7-10 times. I do a starter every time. My question is why do I read about people suggesting you can or should use harvested yeast max four or five times? My starters are always active, my yeast always attenuate, my beer always finishes clear and off-flavor free. How long have you used a yeast harvest and why did you stop using it? I just pitched the same yeast again on another 10 gallon IIpa, and my imperial pumpkin.

Its been said, but it really is sanitization/sterilization. Jamil stated on his radio show that the yeast are really doing good 3rd and 4th generation. He doesn't recommend harvesting yeast if you don't have sanitary practices. He is a bit anal retentive about it, but he uses a pressure cooker to sterlizer the containes he uses for rinsing yeast and storing wort.

Its just not worth losing a batch if you havent taken the time to keep things clean.