Zip Lock Yeast Harvest

[jasonsbeer]

I was poking around threads related to US-05 and noticed a mention of saving yeast from the primary by simply scoping up ~1/2 cup of the yeast cake and storing it in a zip lock bag. Apparently without any additional preparation, just scoop and refrigerate. It was specifically mentioned that the bags were not sanitized, I assume the scoop is.

Obviously, this is much easier than washing.

Does anyone have any thoughts or experience on the long term viability of yeast in this storage method?

I might try it just to get SWMBO to ask me what the nasty bags of goo are in the back of the frige.

 

[duckmanco]

I do the same with sanitized ball mason jars... I swirl up the yeast cake and pour it off into the jars... Done... No yeast washing, just slurry into jars and if I use it within a month, I just pitch, no starter. Works great for me, but I'm sure the bags work well too.... I wonder about the non sanitizing part though.

 

[peanasky]

I wouldn't trust the non-sanitizing part. I know you regularly put food in there, but not stuff you store in the fridge for more than a week or two. I would sanitize it just because if there happens to be some nasty bugs sittin inside there and you go to pitch a month later without a starter, you'll be infecting your whole batch with the nasties.

On a side note, I personally like washing over using just the slurry. The big part for me is that when you re-use the yeast cake (or slurry) you're going to pick up some character of the old beer, in the new beer. (especially for me because I do 3 gal BIAB batches) So it gets difficult to brew say a stout and then use that yeast for an esb without having some side effects. I really only re-use the slurry w/o washing if I'm brewing the same beer again. To each their own and if you're fine with it, I say go ahead!

 

[jasonsbeer]

I was thinking about why washing would be useful. I came up with the same conclusion, that it would minimize the amount of the source beer that works its way into the next. Being a nerdy scientist, I decided to work out the numbers to see how much actually makes it into the next beer. This is a thought exercise based on my equipment and methods. YMMV.

I don't have firm starting numbers, but assume I have 2 quarts of trub in the bottom of the primary. I add 1 gallon of sterilized water and swirl it around to make a slurry. The resulting suspension is now 33% the original trub.

I pour this into a sterile mason jar. I put it into the frige and let it settle out. Even though the solids have come out of suspension, the beer portion that came over remains in the liquid portion. When I decant the liquid portion, the source beer is now gone for all practical purposes. Let's say I now have 0.5 cups of the trub in my mason jar. This is mostly yeast, some proteins, hop junk, and any other misc ingredients in the boil. Percentages of each, I don't know, but I speculate it is mostly yeast, maybe 90% or more. Precipitated proteins the next greatest, say 9%, and hop junk the least, say 1% or less.

I now use this as my yeast in a new 5 gallon batch. The stuff I need to worry about contaminating my new beer are the 10% (proteins+hop junk) of the 0.5 cups, or 0.05 cups. This is 2.5 teaspoons. Doesn't matter if I make a starter, the amount of non-yeast components remain constant. 5 gals is 80 cups. I am adding 2.5 teaspoons of "contaminant" from the previous beer into 80 cups of wort.

The proteins have already left solution/suspension, so they shouldn't have any real effect on the new beer. Any flavor or aroma components in the hop junk portion have been exhausted.

Conclusion: I hypothesize the amount of non-yeast components in the new beer from the previous beer will not have an effect on the flavor or quality of the new beer.

Think I'll quit washing.

 

[seatbelt123]

@jason

Excellent work there! Thanks for the write up.

 

[duckmanco]

I was thinking about why washing would be useful. I came up with the same conclusion, that it would minimize the amount of the source beer that works its way into the next. Being a nerdy scientist, I decided to work out the numbers to see how much actually makes it into the next beer. This is a thought exercise based on my equipment and methods. YMMV.

I don't have firm starting numbers, but assume I have 2 quarts of trub in the bottom of the primary. I add 1 gallon of sterilized water and swirl it around to make a slurry. The resulting suspension is now 33% the original trub.

I pour this into a sterile mason jar. I put it into the frige and let it settle out. Even though the solids have come out of suspension, the beer portion that came over remains in the liquid portion. When I decant the liquid portion, the source beer is now gone for all practical purposes. Let's say I now have 0.5 cups of the trub in my mason jar. This is mostly yeast, some proteins, hop junk, and any other misc ingredients in the boil. Percentages of each, I don't know, but I speculate it is mostly yeast, maybe 90% or more. Precipitated proteins the next greatest, say 9%, and hop junk the least, say 1% or less.

I now use this as my yeast in a new 5 gallon batch. The stuff I need to worry about contaminating my new beer are the 10% (proteins+hop junk) of the 0.5 cups, or 0.05 cups. This is 2.5 teaspoons. Doesn't matter if I make a starter, the amount of non-yeast components remain constant. 5 gals is 80 cups. I am adding 2.5 teaspoons of "contaminant" from the previous beer into 80 cups of wort.

The proteins have already left solution/suspension, so they shouldn't have any real effect on the new beer. Any flavor or aroma components in the hop junk portion have been exhausted.

Conclusion: I hypothesize the amount of non-yeast components in the new beer from the previous beer will not have an effect on the flavor or quality of the new beer.

Think I'll quit washing.

Your idea sounds reasonable too, but I based my decision to wash or not from Chris White of White Labs suggestion not to on a podcast on the BN. Pretty much all I needed to hear.

 

[jasonsbeer]

Your idea sounds reasonable too, but I based my decision to wash or not from Chris White of White Labs suggestion not to on a podcast on the BN. Pretty much all I needed to hear.

A worthy subject matter expert, no doubt. But what is entirely missing is a fact based discussion on why we should wash yeast.

Does washing improve its health? Does it give me a quicker start in the next brew? Does it make them live longer in storage? Do they make better citizens? If the sole purpose is to remove the non-yeast portion of the trub, sorry, that's just not necessary.

I'm not going to wash yeast just to have a feel good moment.

 

[kingwood-kid]

I don't wash because it seems like a lot of trouble to remove something that's already fallen out of suspension once and will be decanted after I make a starter. The tiny amount of trub is a fraction of what I get from an average batch, so I'm not really worried about it carrying over from one batch to another. I store my yeast in bleached water bottles with the strain # sharpied on the outside. Ziplocs might work, but they seem a little flimsy to me, and cost me more than empty water bottles.

 

[jasonsbeer]

After thinking about the different options for a while, I've decided it is easiest to simply save some yeast from a starter. Easier than saving from a yeast cake in a fermenter. Doing this right now with a lager yeast.

 

[Phunhog]

After thinking about the different options for a while, I've decided it is easiest to simply save some yeast from a starter. Easier than saving from a yeast cake in a fermenter. Doing this right now with a lager yeast.

That's what I do. In fact I step up starters for the sole purpose of harvesting yeast. I now have something like 8 vials of WL001 sitting in my fridge that all came from one original fresh vial of yeast. I find it much easier to do than dealing washing yeast from a carboy. I also think it makes a better product since the yeast never had to undertake a full on fermentation, the starter yeast doesn't have hop particles, and it is easier to make, seperate, and store.

 

[badhabit]

So all considered, sure you can harvest from the cake. If you do keep things as clean/steril as possible and use the yeast within 2 to 4 weeks. If you plan on keeping the yeast longer than a month...I don't go more than 2 weeks myself....you will need to harvest and wash.

 

[ReverseApacheMaster]

I seem to recall somebody asked the ziploc folks if the bags were sanitized inside and they said no. Who knows what kind of bacteria may be in the bags.

I wash because it makes it easier to see how much yeast I have and whether it is still viable. It's also necessary for freezing yeast to try to get a pure culture going in the freezer. If I was just keeping the yeast with the intent of using it in a few weeks I wouldn't wash but since yeast sometimes sits in the fridge for months it helps to wash.