yeast storage

[triskelion]

I'd like to reduce how much I spend on liquid yeast by reusing it. the thing is, I probably wouldn't use a fairly specialist yeast like kolsch very often. so what are my options for long term yeast storage? can I freeze a washed yeast?

 

[boswell]

Check the 'slanting yeast' sticky at the top of the page. I haven't done it but the instructions are very detailed.

 

[triskelion]

think I might try keeping a washed jar of yeast in the fridge, some guys on another thread claim that its ok for a year, from their experience. also freezing in yeast in glycerin works well apparently. slants seems to be a bit more involved and it sounds like I would have to make multipal starters to build up the volume.

 

[masonsjax]

Actually Kolsch yeast could be my house yeast. It's great in any style where a clean finish is desired, can serve as a faux lager yeast, and works wonders on wheat and rye beers.

That aside, I plan my brews around the yeast. I will make 5-8 beers on one yeast cake. I wait to keg the finished beer until the day I'm brewing and just dump out some of the cake before racking the new beer on top.

When I brew the first beer of a series, I harvest some of that first yeast cake into mason jars with a teensy bit of beer and stick them in the fridge. When I'm ready to start a new series with that yeast, I'll make a starter and repeat the whole process again. I have successfully made starters from yeast that was in the fridge for close to 2 years without problems. Fresher yeast works better of course, but these days I pretty much stick to the same handful of strains and they get used often.

 

[triskelion]

That's great news for me then! would you say that the beer tastes as good if the washed yeast has been in the fridge that long? im starting to question some reliable sources that say washed yeast only lasts a few weeks in the fridge, when people are storing it for over a year

 

[masonsjax]

I don't wash or rinse my yeast in any way. I believe that process is unnecessary and leads to less viable yeast. I just put some of the cake in the fridge. If a starter takes off from old yeast, and is stepped up to get the desired pitching rate, there should be no difference when compared to brand new yeast used in the same way.

What people mean when they say washed yeast only lasts a few weeks in the fridge, is that without a starter, the viability of the yeast may suffer. If you're letting the yeast sit in the fridge for more than a few weeks, you should probably make a starter.

 

[finsfan]

If you want to be able to keep clean, 1st gen yeast for long term, read this article. I started yeast harvesting (or ranching) after washing yeast once and love the ease and accuracy of harvesting.

https://www.homebrewtalk.com/entries/yeast-harvesting-novel-approach.html

 

[EarlyAmateurZymurgist]

think I might try keeping a washed jar of yeast in the fridge, some guys on another thread claim that its ok for a year, from their experience. also freezing in yeast in glycerin works well apparently. slants seems to be a bit more involved and it sounds like I would have to make multipal starters to build up the volume.

Yeast rinsing is little more than amateur brewer voodoo that is not supported by science. Rinsing a yeast culture with boiled tap water is one way ticket to an infected culture. Boiled water is not sterile (water has to be autoclaved in order to render it sterile), and replacing green beer with boiled tap water removes the protective force field that the culture built for itself during fermentation.

Short of -80C refrigeration, the only viable solution to long-term yeast management is storage on solid media. The most common way to store yeast on solid media is via malt agar or MYGP agar slants.

 

[EarlyAmateurZymurgist]

If you want to be able to keep clean, 1st gen yeast for long term, read this article. I started yeast harvesting (or ranching) after washing yeast once and love the ease and accuracy of harvesting.

https://www.homebrewtalk.com/entries/yeast-harvesting-novel-approach.html

That approach is neither novel, nor does it produce first generation yeast. It does not matter if the culture is maintained as a starter or pitched in a beer. Multiple generations of yeast are generated every time a starter is taken out of the stationary phase via the addition of a carbon source (i.e., sugars).

 

[finsfan]

That approach is neither novel, nor does it produce first generation yeast. It does not matter if the culture is maintained as a starter or pitched in a beer. Multiple generations of yeast are generated every time a starter is taken out of the stationary phase via the addition of a carbon source (i.e., sugars).

You continue to call me out on spreading what I believe to be a resourceful article, that multiple people use. How about calling the author out, or like I have already suggested, starting a new article posting your findings and beliefs instead of saying that way is no good. It is a good way to easily propagate yeast cultures and has worked for me numerous times, as well as many other members here as well.

 

[stratslinger]

Yeast rinsing is little more than amateur brewer voodoo that is not supported by science. Rinsing a yeast culture with boiled tap water is one way ticket to an infected culture. Boiled water is not sterile (water has to be autoclaved in order to render it sterile), and replacing green beer with boiled tap water removes the protective force field that the culture built for itself during fermentation.

Short of -80C refrigeration, the only viable solution to long-term yeast management is storage on solid media. The most common way to store yeast on solid media is via malt agar or MYGP agar slants.

That's an interesting statement that's not at all backed up by the many folks on this board who actively participate in exactly that practice, without running into infection problems.

While I'm sure you're quite correct in that there are infections that can survive boiling, they're apparently all that common to the homebrewer.

Also, as for pitching agar slants or slides as the "only" viable solution, in a presentation at last year's NHC on the subject, covering everything from yeast washing to slanting, the presenter showed several instances where his own slants had suffered from infections. Nothing's foolproof - darned near anything can be mishandled.

 

[triskelion]

how sterile does the water really have to be? I didn't think that a high concentration of yeast could be infected in the same way as wort. I thought that yeast is fairly aggressive in comparison to most airborne organisms.

 

[finsfan]

how sterile does the water really have to be? I didn't think that a high concentration of yeast could be infected in the same way as wort. I thought that yeast is fairly aggressive in comparison to most airborne organisms.

I have used boiled water on top of all the harvested yeast I have and never had a problem. Some have sat for 6 months + and still made great beer

 

[tagz]

Yeast rinsing is little more than amateur brewer voodoo that is not supported by science. Rinsing a yeast culture with boiled tap water is one way ticket to an infected culture. Boiled water is not sterile (water has to be autoclaved in order to render it sterile), and replacing green beer with boiled tap water removes the protective force field that the culture built for itself during fermentation.

Short of -80C refrigeration, the only viable solution to long-term yeast management is storage on solid media. The most common way to store yeast on solid media is via malt agar or MYGP agar slants.

you called yeast rinsing "voodoo" science but then referenced a "protective force field" to describe your method. i can't imagine that boiled water is less sanitary than sugary wort that has been passed through several pieces of equipment. you are very adamant about your position against using boiled water, which is fine, but short of any experimental data your experience does not outweigh anyone else's.

 

[masonsjax]

EarlyAmateurZymurgist might not have the most delicate delivery, but plenty of evidence exists to support his statements. Are you open minded enough to view all of the available evidence before deciding? Just because it works for many homebrewers, doesn't mean it's the best choice. Dig around, there's a lot of interesting data published on all sorts of controversial homebrewing practices that fly in the face of conventional wisdom and introduce new methods perhaps not thought possible before. I for one welcome new evidence that can help me improve my beer, and welcome those that point me toward the light.

 

[SpeedYellow]

Yeast rinsing is little more than amateur brewer voodoo that is not supported by science...

I'm starting to like this guy.

I have no idea where this yeast rinsing idea came from, but it makes zero sense to me.

 

[tagz]

EarlyAmateurZymurgist might not have the most delicate delivery, but plenty of evidence exists to support his statements. Are you open minded enough to view all of the available evidence before deciding? Just because it works for many homebrewers, doesn't mean it's the best choice. Dig around, there's a lot of interesting data published on all sorts of controversial homebrewing practices that fly in the face of conventional wisdom and introduce new methods perhaps not thought possible before. I for one welcome new evidence that can help me improve my beer, and welcome those that point me toward the light.

I'm more than open to it. I have no loyalty to one method or another. But EAZ is a pretty vocal critic of any method other than his own, but he never offers anything other than conjecture. I'd be happy to look at the "interesting data" you guys are finding. How about a link?

 

[Brewitt]

Check out the article in the link at the bottom of this post. It gives the technique a group of us has deduced for freezing and long term storage of yeast. It works.

 

[tagz]

From Woodland's blog:

Most bacteria can be killed by flash pasteurizing. (2)(3) Tap water contains very little bacteria to begin with because there is no nutrients. For bacteria to grow both nutrients and water are required. Dry sugar also contains very little bacteria because there is no water. Therefore the amount of bacteria that may need to be killed is small. Heating to 165°F or above for a minute or longer is sufficient for most brewers.

Yeast that has been packaged for storage in a refrigerator is typically not stored with any food for the yeast because it is intended to stay dormant. When the yeast warms up to room temperature it will become active, and during this time the cell population will increase slightly, however it quickly runs out of energy reserves. The bacteria, on the other hand, will feed on the dead yeast cells, and continue to propagate even after the yeast have stopped growing.

During a test of two strains of yeast, WLP004 and WLP566 It was noted that within the first 12 hours both strains grew in population. Initial inspection of the yeast when it was removed for the refrigerator showed no signs of bacteriological activity, but after only 12 hours pairs of bacteria were observed indicating cell growth.

In four test cases the viability was not statistically different in these layers. Tests were run with three slurries with 10%, 50% and 90% viability. In all tests the viability of the yeast in each section did not vary more than one standard deviation.

What was interesting was that the bacteriological content was much higher in the top portion of the yeast containers than in the lower parts. There was about 100 times more bacteria per live yeast cell in the top "liquid" section.

Edite: Brewitt - I've read through your article before. Great stuff. I haven't moved into freezing yet, but may do so down the road. Thanks.