Should I add nutrient to reused yeast?

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Closet Fermenter

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I just started my third consecutive use of a SafAle S-04 in my fermenter. First use was a dry pitch. The second was a closed transfer followed by new wort. The third (yesterday), was new wort after keeping the the fermenter refrigerated after the transfer the day before.
The first start up was typical. The second nearly blew the StarSan out of the bottle as soon as I hooked up the blow off. The third paused for a little while, but when I checked back an hour later, it was motorboating along. Note: I did pull the fermenter out of the fridge a few hours before adding the wort.
My question is; should I be adding anything to keep the yeast healthy and vigorous as I move into multiple uses?
Should I do anything differently if I harvest the yeast from the fermenter and refrigerate for later use? What would you consider as the limit on reusing yeast?

Thanks for any advice!
 
there are dead yeast cells in that yeast cake. I believe the live yeast uses that as "food" or "nutrients".

You might want to pour off about half that yeast cake into a mason jar to save for another day and then pitch on the remains.
 
You might want to pour off about half that yeast cake into a mason jar to save for another day and then pitch on the remains.

OK. This is doable. My initial thought was that the risk of infection was greater than the risk of over pitching. I have been considering adding a valve to my fermenter (which is stainless and valveless), which would make removing some of the yeast easier and could be done without opening up the lid, but more troublesome to sanitize and more difficult to manipulate in my space-limited brewing area. (I have not even opened the lid to refill, but dumped wort in through the triclamp opening I added to the lid.)

My plan is to harvest yeast after this run and rest for a future brew. Thanks for the advice.
 
My question is; should I be adding anything to keep the yeast healthy and vigorous as I move into multiple uses?
I have read that after a few uses, yeast can get low on zinc. Many of the nutrients intended for cider/mead/seltzer do not have zinc. The White Labs yeast nutrient is one that I know has zinc and is sold at my local shops.
 
Breweries harvest yeast for reuse. They add nutrient in the kettle for each batch. They also pitch an appropriate amount of yeast. If i understand correctly your siphoning off beer and adding fresh wort on top of your yeast cake (and trub). Thats way over pitching plus your building up new trub with each batch. Id recommend either keeping a starter going and using a portion each time or harvesting the yeast by washing. If you can make beer without infection theres no reason to be worried about harvesting yeast and infections. Slightly different protocols but nothing too crazy needs to be done. If your really up for it get some chlorine dioxide for washing yeast. My 2 cents. Cheers!
 
Breweries harvest yeast for reuse. They add nutrient in the kettle for each batch. They also pitch an appropriate amount of yeast. If i understand correctly your siphoning off beer and adding fresh wort on top of your yeast cake (and trub). Thats way over pitching plus your building up new trub with each batch. Id recommend either keeping a starter going and using a portion each time or harvesting the yeast by washing. If you can make beer without infection theres no reason to be worried about harvesting yeast and infections. Slightly different protocols but nothing too crazy needs to be done. If your really up for it get some chlorine dioxide for washing yeast. My 2 cents. Cheers!
Thanks for this. Based upon comments received, I will be modifying my procedure. This is not something that I have been doing for a long time. Just within the past 6 months, I started doing closed transfers. So, while the fermenter remained closed, I figured it was safe from possible infections and prime for reloading. I realized that each successive batch was going to increase the trub level, but in the short run, I have the option of using a floating dip tube in my fermenter.
I had predetermined that this was my last run and that I would harvest yeast and reboot for later.
I will look into best yeast harvesting practices. Thanks again!
 
Zinc is the only nutrient that wort is deficient in. You can probably get close to a dozen generations before you start noticing it by the tail end of the fermentation being sluggish and the beer never quite fully attenuating. If you reuse the full yeast cake, you'll probably get more than a dozen -- if you throw out almost all of the yeast slurry every round, you're also throwing out almost all of the zinc in the pool. I use Servomyces, which comes in 10g packs and is enough for 10hL (roughly 8.5bbl or 250gal) of beer. You can also use a zinc salt (e.g. zinc sulfate), but the amounts you need for a homebrew size batch are so minute, that you probably need to make a dilute solution first to have any hope of the correct dose.

A closed transfer out of the fermentor doesn't prevent contamination unless you're doing a sterile transfer into the fermentor. That said, it shouldn't matter all that much. I've reused yeast for about 2 dozen generations from open fermentations. Sometimes the yeast does get contaminated, but you might be able to recover with a phosphoric acid wash (drop the pH to 2.0 for about 30min). It's up to you if doing an acid wash is "worth it", but it's literally 5min of work after the first time you do it.

I've had bad experiences if I kept a yeast slurry harvested from the bottom of the fermentor after transfer for more than 2-4 weeks before reusing. With other methods (top-cropping or overbuilding) it lasts for months and months and probably at least a year.
 
Zinc is the only nutrient that wort is deficient in. You can probably get close to a dozen generations before you start noticing it by the tail end of the fermentation being sluggish and the beer never quite fully attenuating. If you reuse the full yeast cake, you'll probably get more than a dozen -- if you throw out almost all of the yeast slurry every round, you're also throwing out almost all of the zinc in the pool. I use Servomyces, which comes in 10g packs and is enough for 10hL (roughly 8.5bbl or 250gal) of beer. You can also use a zinc salt (e.g. zinc sulfate), but the amounts you need for a homebrew size batch are so minute, that you probably need to make a dilute solution first to have any hope of the correct dose.

A closed transfer out of the fermentor doesn't prevent contamination unless you're doing a sterile transfer into the fermentor. That said, it shouldn't matter all that much. I've reused yeast for about 2 dozen generations from open fermentations. Sometimes the yeast does get contaminated, but you might be able to recover with a phosphoric acid wash (drop the pH to 2.0 for about 30min). It's up to you if doing an acid wash is "worth it", but it's literally 5min of work after the first time you do it.

I've had bad experiences if I kept a yeast slurry harvested from the bottom of the fermentor after transfer for more than 2-4 weeks before reusing. With other methods (top-cropping or overbuilding) it lasts for months and months and probably at least a year.
Thanks. Right, I knew that this was not entirely without contamination risk. When adding the new wert, it was through a 2” triclamp opening in the lid; so minimal exposure, but a risk nevertheless.
I tried this after a yeast harvest failure, that was like you stated, beyond a few weeks in the fridge. I am unfamiliar with the topcropping and overbuilding methods you mentioned. Do you know of a good place to read up on this?

Thanks again!
 
Thanks. Right, I knew that this was not entirely without contamination risk. When adding the new wert, it was through a 2” triclamp opening in the lid; so minimal exposure, but a risk nevertheless.
In my "opinion", homebrew is always a bit infected. The key is keeping the infection at a level where it doesn't start showing problems during the expected drinking life of the beer. Infection is not really a problem with high-attenuating (esp. diastatic) yeasts, as long as your initial pitch allows the yeast to dominate. It's quite a problem with maltotriose-negative yeasts, because then you're also competing against your previous brewer's yeasts unless your cleaning is 110%.
I tried this after a yeast harvest failure, that was like you stated, beyond a few weeks in the fridge. I am unfamiliar with the topcropping and overbuilding methods you mentioned. Do you know of a good place to read up on this?
I can't think of a canonical resource covering both. E.g. the book "Yeast" has material on bottom and top cropping. In short, top-cropping is spooning off the krausen to harvest yeast. It works only with yeasts that produce a rich krausen, but it gives you healthy yeast that you can let finish fermenting for a day or so, and then refrigerate. When you go to reuse it, decant the liquid and -- in most cases -- drink it. For some yeasts it might be heavy in diacetyl, but for others it's almost like the beer you cropped it from.

Overbuilding is making a starter larger than necessary. In my *opinion*, it's more of a smoke&mirrors game, because unless you do cell counting, you have no idea how much yeast you have. I just make "a starter" and then pitch half and save half. I try to avoid the technique especially if I have to use DME, because at least for dry yeast I might just a well splurge the 2-3EUR on another packet as opposed to the cost of DME and extra work. So, for bottom-cropping yeasts I try to plan my brews so that they're back-to-back[ish] and I can reuse the yeast latest in a week or so. I get a few generations out of it, and then I'm done -- I enjoy being frugal, but not too frugal.
 
I have had nothing but evident success using yeast propagation calculators (primarily the Homebrew Dad calculator) and have no reason to abandon the practice. I always do overbuilds and have had strains run for years...

Cheers!
 
I have had nothing but evident success using yeast propagation calculators (primarily the Homebrew Dad calculator) and have no reason to abandon the practice. I always do overbuilds and have had strains run for years...
I also had success with yeast calculators. Then I stopped using them and generally making dedicated starters, but the success remained. Granted, I work "starter beers" into the pipeline if I want to brew a high-octane beer, but I enjoy low-octane beers (10-12 plato) and mostly drink those anyway, so it works for me. For e.g. someone who brews only high-octane, my method wouldn't work so well.
 
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