Some yeast handling, washing, and storage questions

[CthulhuDreaming]

So I've been brewing for quite a few years, and to this point have always used dry or liquid yeast from the LHBS. While dry yeast is fairly economical, liquid yeast is not, and it's what I would prefer to use. In the past, I didn't have the ability to store yeast between batches, but I think I can probably manage it now.

I've been reading up on the yeast washing process and it looks pretty straight forward. I'm left with a few questions before I get started actually doing it. (I'm referencing the stickied Yeast Washing Illustrated thread).

1) Is it reasonable to store the washed yeast in flip-top bottles (e.g. Grolsch) rather than mason jars? I suspect the main concern here would be in the sanitation of the rubber seal. Any other issues?

2) Is there an optimum storage temperature? The sticky says to refrigerate, I'm thinking normal refer temperature is fine, and that below freezing or room temperature is bad (i.e. above refer temp). True?

3) Generally speaking, how long does washed yeast stay viable? Days? Weeks? Months?

4) Let's say I start with the dregs from a batch fermented with a starter made from a good, viable, fresh liquid yeast from the LHBS. Is there a practical limit to how many times I can recycle the yeast as long as my colony remains viable in storage? In other words, as longs as my latest batch had a healthy fermentation, is there any reason why I should not continue to harvest, wash, and reuse indefinitely?

I suspect that the standard RDWHAHB response applies to most of my questions.

 

[Kayos]

1. those are fine. Many people use them.
2. true- fridge temp is fine
3. 1 year is a good time frame
4. 3-5 times. I have heard up to 10, but if you get 5 yeast slugs per batch, that's a lot of yeast! I wash 3 times and call it good. That's 15 batches per $5.75 of original yeast. I think that's quite a deal!

 

[rmonty]

A few years ago I was looking into decreasing the cost of my ingredients. As a general rule, liquid yeast is the most costly (even Notty is getting up there now ). Anyway, I got excited when I read the 'Frozen Yeast Bank' and 'Yeast Washing' threads. Now, I buy a strand of yeast once ... once (throw in your best Danny Vermin/Joe Piscopo voice here).

If you harvest from each batch and split the washed yeast into 5 containers (mason jar, growler, sheep's bladder, etc), the # of brews you can make are extreme. To be honest, the most difficult part is organization and keeping good records (I'm lazy that way).

Gen 0: Vial from LHB
Gen 1: 5 containers of washed yeast
Gen 2: 25 containers of washed yeast
Gen 3: 125 containers of washed yeast
Gen 4: 625 containers of washed yeast
Gen 5: 3,125 containers of washed yeast
Gen 6: 15,625 containers of washed yeast
Gen 7: 78,125 containers of washed yeast
Gen 8: 390,625 containers of washed yeast
Gen 9: 1,953,125 containers of washed yeast
Gen 10: 9,765,625 containers of washed yeast

Granted, there is a need for a reality check and some common sense. I'm not about to brew up a million batches of anything and I will occasionally 'reset' the yeast I use the most.

-Rob-

 

[leo_n_davies]

I just started saving yeast a few months ago. I make a starter a day or two before each brew day. I use 3 quart jars of wort I made in a canner heated to 250 degrees in a pressure canner (to make sure no botulism spores are present). This means I don't have to make and boil wort for a starter each time I brew. On brew day I pour half of the starter into a 2 quart jar and pitch the other half. After a day or so in the fridge I pour the liquid off the top of the saved yeast and transfer the bottom slurry to a sterilized pint jar. I understand that the yeast will be good for 6 months. So far works well. The saved yeast starter kicks up and gets a good kreusen, so appears OK. I may be incorrect, but if the yeast numbers decrease due to age it will still work.....but may take longer to get going on the stirstarter plate. Once it has a good kreusen in 3 quarts of starter there should be plenty of yeast....right? I make my starter two days in advance right now......if I use some really old yeast maybe it would take three days?

 

[monkeymath]

I have no knowledge on the matter and only limited experience, but I'd just like to add that ime some yeast strains seem to lose viability more quickly than others.

I generally don't wash my yeast, but just store the entire trub from the bottom of the fermentor, then make a starter from a bit of that trub (don't want to dump one batch's entire trub into the next) for the next brewday. So things might be different if you do wash.

With one yeast, after about a month of storage, the starter was raging in no time and then ripped through the wort. With another yeast, I had to dump the starter because it just wouldn't take off within 48 hours. In those cases, it's good to have a dry yeast on hand so you don't have to call off your brewday.
(The second time, the yeast was actually harvested from a lower ABV beer, just in case anyone is wondering.)

 

[GrowleyMonster]

My beers don't usually differ a lot from one batch to the next, so I mostly use harvested yeast. After 5 generations I had some unexpected results though in retrospect it probably had nothing to do with the yeast, and I started over again with dry. I am thinking about switching to Hornindal and I will therefore be starting again. If you get 4 or 5 consecutive batches from one yeast purchase, that's almost free yeast. Remember that yeast do mutate and there is some Darwin action in the fermenter, with cells genetically gifted at munching your wort in your fermenter under your conditions predominating in your house strain. After a couple generations it is indeed very much your own house strain, even though it is based on and shares many characteristics with the parent commercially packaged yeast.

Nevertheless, sometimes stuff happens, and you end up having to retire a strain and begin again. And here is the big question... begin... from what? Another packaged and purchased yeast? Or a washed sample from the original batch, or a frozen sample? Washed yeast ought to be usable in a starter at up to a year, so I read. Even with live cell count down to 10% of original, you should still be able to make a starter from it if the starter medium is pasteurized and uncontaminated. So you decide your house yeast active strain is ready to be replaced after several generations. You can reach in the back of the fridge for that carefully stored sample from a half dozen generations ago, and bring it back to life, and essentially reset the clock to generation #2.

I have been reading a lot on freezing yeast. There are a couple of threads on this, and some reddit posts and other resources dealing with the freezing of yeast. If you have say 10 frozen samples, that is 10 resets. The process seems pretty straightforward, just add a water and glycerine solution to clean yeast slurry, and freeze. Knock on wood, cause I haven't done this yet, but when I start over with the Hornindal Kveik I fully intend to both refrigerate and freeze harvested yeast.

All that aside, up to now I haven't seen the need in my own brewhouse to wash my yeast. Your requirements could be different from mine. My beers are all fairly heavy and lightly hopped ales. Conventional wisdom and logic both point to not using a big beer yeast harvest to pitch to a lighter beer. Vice versa? That would be an interesting question. But for me, my batches have only very slowly changed and evolved from when I switched from extract based brewing to BIAB.

I have just started using the Australian style no-chill process. The hot wort from the boil kettle goes directly into a 5 gallon (actually almost 5.5 gallon) HDPE "cube" jug, and all the air is squeezed out so that there is essentially zero headspace. The wort can then cool naturally over the course of 24 hours and can be kept for a few days, even, before transfer to fermenter. There are a few issues that must be addressed such as DMS formation, boil time, hopping schedule, etc but basically that's it. No chiller is used, and transfer to fermenter is delayed a day or two. What else good that does for me is it allows me to make a starter from the exact same wort that I will be pitching to, because I can quick chill a quart of wort in an ice bath in the sink, then pitch my yeast sample into it, and it is worked up to a frenzy by the time I am ready to pitch into the fermenter. My sample is usually just saved in a zip lock bag, scooped directly from the yeast cake, and not washed. This amount is so small, usually 1/4 cup or so, that I am not even slightly concerned about introducing raw trub into a 5.5 gallon batch. I don't dry hop, and my boiled hops are always in a hop sock or hop spider, so there is minimal potentially noxious plant matter in that tiny harvest, anyway.

If you do any reading on Norwegian farmhouse yeasts and how they save the dried yeast on sticks or wooden rings and hang them in the open to dry, you might re-think how much trouble we often go to, in keeping yeast clean and uncontaminated. The Norwegian farmhouse process is almost disgustingly simple, and they use the same yeast strain for many generations. Not many generations of the yeast. Many generations of the family using that strain. And this is where we get all those fascinating kveik strains from that are getting to be so popular. Not saying that such primitive and unrefined methods will work great with our pampered and pedigreed yeasts that we get in nice neat little packages, no. But sometimes maybe we obsess with details because we believe that they make a difference, and often they do make a difference. Sometimes we obsess with details just because we enjoy the minutae of brewing. Sometimes some of those details aren't really "necessary". So YMMV, but washing could well prove for you to be one of those usually unneccessary details, depending on your brewing style and practices.

Final word... it is always good to have a pack of dry yeast in the fridge for backup, along with a backup harvested sample or two. The harvested sample is your last chance to keep going with the same strain. You know that the dry will go to work in just a few hours, no matter what, so it is your last ditch for sure gonna work option. Another $5.75 down the drain, though.

 

[odie]

1. not really. easier to clean, sanitize and fill mason jars. they are clear so you may observe your yeast...is it clean or do you see nasties growing...kinda hard with a green bottle.

2. fridge yes, freezer no.

3. sniff test...does it smell like yeast/beer or does it smell funky...it can go bad in a couple weeks or stay good for over a year. trust your nose. this really depends on how clean your storage container is and how clean your harvesting handling methods are. If the yeast spoils, it's because something YOU did or did not do.

4. forever. It good to reuse until its not. there are breweries that are propagating the same yeasts for centuries. as long as you are happy with the results.