Yeast starter in my fridge for 2 months.. can I revive for next batch or should I toss?

[luckybeagle]

I brewed a Belgian style Tripel on 12/20/2018. I saved the yeast cake/slurry and grew a 3L starter out of it. On 1/5/19, I pitched 1.5L of that starter into a Belgian style Blonde, which turned out super tasty--the other 1.5L has been in my fridge since.

I want to re-brew the Tripel again and would love to use the same yeast--the beer took 2nd place in the Trappist category and had super high attenuation, so I'd love to reuse this exact batch of yeast if possible--but I don't know if it's realistic to expect it to not have mutated over 2+ mos of cold storage.

Is it inadvisable to decant the liquid and make a fresh starter out of the cake for the next tripel? Or should I just buy another packet of Ardennes yeast and start over?

 

[tgolanos]

I routinely use my yeasts for several generations, even if it's been in my fridge for 2 or so months. Give the slurry a sniff - if it smells like it should, use it. You may not need to make a starter, depending on how much slurry you have. Just warm it up, decant, and ferment away. If it has any off-scents or smells funkier than it should, toss it, it's not worth the risk.

 

[ProblemChild]

its fine. two months is nothing. If sanitation is good, yeast will work.

 

[SoCal-Doug]

Sure. Some of the cells of course are dead, but there should be something live in there.

We successfully culture and restart dregs from bottle conditioned beers that are 3 and 6 months old. All it takes is one live cell and enough time to get them multiplying.

 

[luckybeagle]

Thanks all! Looks like I'm squared away on both hops (misc magnum for bittering) and plenty of WY3522). Should make for a nice, cost-efficient brew day in the near future

 

[luckybeagle]

Hmm. It looks like the foil I had sealing the yeast starter had started to break down. I dont think any dropped into the liquid, but there were a few pin-sized holes in it. I tasted the liquid on top of the yeast slurry and it tasted like the signature Ardennes strain, maybe a little bitter. When in doubt, throw it out?

 

[Kickass]

Going off only what you've written, I'd probably use it. BUUUT, sometimes I brew fast and loose without my seatbelt fastened.

 

[SoCal-Doug]

Make a starter. See what it smells and tastes like.

 

[IslandLizard]

I think the chances are small that much could have dropped through those pinholes and would harm your yeast culture or your next brew. There's alcohol in the beer on top, and an abundance of yeast to crowd out intruders.

Many years ago, pretty much since I've been making starters, I've seen those pinholes in the foil develop within a few hours to a day, even in thick heavy duty foil. I have been simply covering the foil tent with a double layer of Starsaned plastic wrap. Problem solved.

I'd pour off most of the supernatant, leaving just enough behind to swirl the yeast/trub up into a thick pourable slurry and pitch as is. 2 months in the fridge is not that long, it's very viable and live cell count is still high.

Or if you have time, make a new starter with some of that slurry and see if anything else grows in there. Use a yeast calculator to estimate starter size.

 

[balrog]

Your nose & taste buds are fairly good at determining whether you use it. If it looks good (no undulating black furry things), smells and tastes good (not like lady gaga's meat dress left in the las vegas sun for 12 weeks), then you're really in pretty good shape.

I seem to have lost my appetite for breakfast. Sorry about that.

 

[NeverDie]

What causes the foil to develop pinholes? Because it was sprayed with StarSan, and the StarSan acid ate away at it? Or, is it for some other reason?

 

[RM-MN]

I brewed a Belgian style Tripel on 12/20/2018. I saved the yeast cake/slurry and grew a 3L starter out of it. On 1/5/19, I pitched 1.5L of that starter into a Belgian style Blonde, which turned out super tasty--the other 1.5L has been in my fridge since.

I want to re-brew the Tripel again and would love to use the same yeast--the beer took 2nd place in the Trappist category and had super high attenuation, so I'd love to reuse this exact batch of yeast if possible--but I don't know if it's realistic to expect it to not have mutated over 2+ mos of cold storage.

Is it inadvisable to decant the liquid and make a fresh starter out of the cake for the next tripel? Or should I just buy another packet of Ardennes yeast and start over?

Hmm. It looks like the foil I had sealing the yeast starter had started to break down. I dont think any dropped into the liquid, but there were a few pin-sized holes in it.

It's been in your refrigerator at what temperature? Chances are it is nearly as viable as the day you put it in there unless it froze or your refrigerator quit and it got hot. Being in the refrigerator the chances of anything bad getting in it through the holes in the foil are slim too.

http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html

 

[IslandLizard]

What causes the foil to develop pinholes? Because it was sprayed with StarSan, and the StarSan acid ate away at it? Or, is it for some other reason?

Yup! And it can happen as fast as within an hour of submersion in a bucket with Starsan.

I'm not sure why it develops pinholes, maybe they are in weak areas in the foil. Or they are there already and become larger. Creased areas are more susceptible.
The foil doesn't dissolve into larger holes, even after being submerged for a week. But you may get more pinholes.

 

[luckybeagle]

Thanks, I have renewed confidence in using this yeast! Makes sense about the massive yeast slurry and boozy liquid on top being at least a little tolerant of pesky invaders. Love saving $ on batches--it means more frequent brew days!

 

[hottpeper13]

What I do in your sitch is, take the yeast out at beginning of brew day and decant. After the wort has boiled for 10 min. I pull a quart mason jar out and chill in freezer, when chilled enough pitch it on the yeast cake and watch it take off. This is called a vitality starter and you pitch the whole thing.