Autolysis in Starters after a few+ days in the fridge

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matt_m

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I've recently developed a problem with starters that sit in my fridge for a few days developing a strong "soy sauce" smell which I believe is autolysis. I'm following a pretty standard procedure--1/2 cup of DME with 1 quart of water and a little yeast nutrient, boil 10 minutes, chill by leaving the covered pot in a a sink full of water for an hour or so. I put that in a sanitized flask on a stir plate, ad the yeast, and cover loosely with foil. I stir at a speed just below where the the funnel hits the magnet and makes a racket. The starters take off fine, and once the krausen starts to settle down I stick it in the fridge until I use it. My basement is generally cool and according to a smart thermostat can drop to ~60-62 at night and we heat it to about 68 when occupying the space.

The pot and flask are dedicated to starters. The flask I store in a cabinet with a little sanitizer and the stir bar inside and a piece of foil tightly over the top, then re-sanitize before use. I don't think it's a contamination issue.

I haven't been making as many starters in the past year as I've found with Imperial Yeast, I just don't need them so I don't have a ton of samples. Maybe 3 or 4 failures in 5 or 6 tries so a high failure rate. The starters I've had trouble with have been both older (but not ancient) sealed pouches and yeast from a previous batch that was stored around 2 weeks. Maybe it's the yeast I'm starting with? I'll generally make a starter around Wednesday for a weekend brew day. Sometimes plans change and they sit a week. I haven't let one sit for a week successfully in a while.

The fridge is a chest freezer with an Inkbird. I keep my pouches of yeast and several other things in there without an issue. I don't think its a storage temp issue. Maybe that's a bad assumption.
 
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matt_m

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No, I was thinking I didn't have a way to do that but I do have an air probe for my Thermowerks Smoke now that I think about it.

The next question I guess would be whether autolysis is the result of warm temps or too cold?
 

day_trippr

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fwiw, I used to maintain a handful of different yeasts strains via over building starters and often would have a jar of a less frequently used strain (eg: 3787) sit for six months or even longer and still be viable and sans any off notes. I would vote for contamination to have a sample turn so quickly...

Cheers!
 

ebbelwoi

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Maybe there's contamination coming off of the sides of the cooled pot or something like that? Do you sanitize the sides before and after cooling? That's the only thing I can think of.

I boil and cool right in the flask, and I know mine can handle the heat and the thermal shock, FWIW.
 
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matt_m

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It could be. I have a pot I keep in my brewing area I only use for starters on a cheap induction plate. I fill the sink with a 2-3 inches of my city's finest overly-chlorinated cold water and set the pot in there with a lid to cool. The sink isn't gross but also isn't sanitized. The lid sits on the pot until the wort boils, half on during the 10 minute boil. I wash it after use and put it in the cabinet until next time. I guess I've never thought about sanitizing the pot and probably should spritz the outside with sanitizer before pouring. Flask, foil, stir bar, and funnel all go in my Star San bucket while the boil is happening and I pull them out when the wort is cool. Yeast packets and scissors get sanitized, jars of recycled yeast I sanitize, dump off any beer on top, reclose, and sanitize before adding to the starter. If the flask feels warm after dumping the wort in, I'll shoot it with an IR thermometer so no contact there.

I remembered I bought one of the recording Inkbird temp/humidity sensors. I put it in the fridge for several hours and it was a pretty constant 37 sitting on a layer of cans in the bottom which is where I'd typically set a starter.

I've got a several-week-old jar of US-05 in my under-bar fridge. I think I'll run some trials next week and see what happens. For one, I think I'll put the flask in our regular fridge just in case there's something going on there.
 

McMullan

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To practice better sanitary technique you could bake the flask @140°C for an hour or so then pour in hot starter wort while the flask is still hot. But I suspect the issue is more likely starting with yeast of low viability and low vitality in the first place, which are more likely to get a noticeable infection. Yeast passed their best ideally need to be stepped up gradually to bring them back to a pitch able condition, high viability and high vitality. Otherwise the risk is 'crap in crap out'.
 

McMullan

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Another possibility is the starters are being stored in the fridge too soon, before they're finished and the temperature change shocks the still-active yeast cells. Even when the yeast drop there can be a lot of activity going on. Even when it looks done. Try leaving the starter at room temperature for another day or so. It can take 48-72 hours for a healthy culture to finish and go dormant. If storing in the fridge prior to pitching you want them dormant.
 
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matt_m

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That could be it too. Going back a ways I always did starters on recently purchased Wyeast/White Labs/Omega products which I generally purchased within the last couple months if not weeks. When I got a chance to try Imperial I took the advice to just pitch it right out of the pouch and I found it takes off just as well if not better so I cut way back on starters. Around the end of last year I got a yeast harvester and have renewed interest in reusing yeast to make purchasing logistics a little easier (I can easily pick up Imperial products every 6-8 weeks or less during the school year, summer I have to drive about 50 miles each way) but haven't developed any habits about how to manage it.
 

Miraculix

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That could be it too. Going back a ways I always did starters on recently purchased Wyeast/White Labs/Omega products which I generally purchased within the last couple months if not weeks. When I got a chance to try Imperial I took the advice to just pitch it right out of the pouch and I found it takes off just as well if not better so I cut way back on starters. Around the end of last year I got a yeast harvester and have renewed interest in reusing yeast to make purchasing logistics a little easier (I can easily pick up Imperial products every 6-8 weeks or less during the school year, summer I have to drive about 50 miles each way) but haven't developed any habits about how to manage it.
Just an anecdotal advice from me regarding direct pitching Imperial pouches, just do it when they are reasonably fresh, one month is already too much. I've made bad experiences with older packages due to bad viability. A starter would have probably saved the poor beer...
 
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matt_m

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Curious, what's your batch size? I've been doing 6.5ish gallons into the fermenter and using them up to a few months old with good results. Are you having them shipped? I've been really hesitant to have yeast shipped and having it freeze or get too hot.
 

Miraculix

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Curious, what's your batch size? I've been doing 6.5ish gallons into the fermenter and using them up to a few months old with good results. Are you having them shipped? I've been really hesitant to have yeast shipped and having it freeze or get too hot.
Shipped within Germany, not much chance for freezing it on the way or getting too hot atm. Pretty much perfect shipping temperature everywhere here. The last pack that made problematic beer was 5 months old but they claim enough cell count for six months. Batch size was about 20 liters.
 

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FWIW I agree with the prior post garbage in garbage out as far as the yeast is concerned. I would definitely eliminate the transfer of the started wort from pot to flask. Clean the flask with hot PBW and then sterilize the flask and foil cap in the oven at 270F for 20 minutes, then let it cool down until it's warm, add your DME and water and boil (make sure the flask is rated for direct heat) it in the flask for 15-20 minutes covered with the foil. When the wort is at pitch temp 75-80 degrees, pitch a fresh package of room temperature yeast which you have wiped down with vodka including the scissors as you were doing. A lot of these points were made earlier but are worth repeating. I would recommend a packet of Wyeast with the nutrient pack which you should burst just before pitching it, and when you put it on the stir plate (clean the stir bar and soak in a little vodka) keep the temperature higher 73 - 80F, your propagating yeast not fermenting beer. Any off flavors produced from the higher temps can be eliminated by decanting the spent wort prior to pitching. Keep it on the stir plate for 24-48 hours (73-80F) then place it in the fridge and let the yeast drop down prior to pitching. Make sure the starter and the wort are at the same temp when pitching.
If you still end up with a contaminated starter you need to leave the building ASAP, you have bigger problems.
Good Luck
 

IslandLizard

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My basement is generally cool and according to a smart thermostat can drop to ~60-62 at night
That nightly temp drop doesn't sound good for yeast propagation or fermentation purposes in general, unless secondary heating is applied.
we heat it to about 68 when occupying the space.
What is the temp range when you're not heating? 66-68F is about the minimum for (most) yeast propagations.
 
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matt_m

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It can get as low as 60 at night in the winter. But we only heat the house to 62 at night in the winter so upstairs wouldn't be much better. Maybe I need to get small heating mat I can wrap around a flask. I've always seen an obvious change in volume in yeast slurry...doesn't mean it is/was viable yeast.
 

marc1

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Here's what Escarpment Labs recommended in a webinar:

 
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matt_m

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Thanks everyone. I am going to start doing some experimentation this week. I have some clean, fresh US-05 available from a batch of cream ale in one of my fermenters, 4-6 week old US05 from another beer, and some old pouches of 1010 from last summer so I'll try each over the next couple weeks and see what happens. I'll put everything I can in the oven to sterilize them to be safe. Then I'll go from there following tips from above. Hopefully its just bad luck and lazy practice and I'll have a bunch of yeast I need to use up the next few weekends.

I'm a little concerned about the flasks on a open flame on the gas stove so I need to read up on that. In my brewery I just have an induction plate. One of them is a Pyrex, one is a Chinese knockoff but maybe a way to handle that is to do a double boiler setup?
 

RM-MN

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Thanks everyone. I am going to start doing some experimentation this week. I have some clean, fresh US-05 available from a batch of cream ale in one of my fermenters, 4-6 week old US05 from another beer, and some old pouches of 1010 from last summer so I'll try each over the next couple weeks and see what happens. I'll put everything I can in the oven to sterilize them to be safe. Then I'll go from there following tips from above. Hopefully its just bad luck and lazy practice and I'll have a bunch of yeast I need to use up the next few weekends.

I'm a little concerned about the flasks on a open flame on the gas stove so I need to read up on that. In my brewery I just have an induction plate. One of them is a Pyrex, one is a Chinese knockoff but maybe a way to handle that is to do a double boiler setup?

Put them in the oven, heat to 350, then let cool slowly.
 

Control Freak

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If you're going to run an experiment one of the first things you need to do is eliminate variables or you won't be able to accurately determine where the problem lies. Use a fresh pitch of store bought yeast and that will eliminate one big variable. Brew a beer that only requires a pitch from a single package of yeast. If the beer does not work, start back tracking, but If the beer comes out ok you can start adding one variable at a time like making a starter but again use a fresh pack of yeast. If that beer works then introduce a harvested yeast.
Eventually you will identify the issue, or perhaps just by correcting any sanitation problems during the process end up getting a good result. In addition try to control your temperatures across the board.
Be Patient
 
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matt_m

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My plan was to thoroughly sanitize everything, reduce transfers, and see if using that same process results in good yeast from both new and old yeast. Then I know either my sanitation or process was a problem.
 
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