How to Guide on Yeast Washing and Yeast Freezing(for storage) - With Photos

This is the procedure i follow when washing yeast from a previous batch, and then preparing it for storage in the freezer.
I have had very good results so far:

1. Sanitize a 2 liter container(this will hold the washed yeast overnight)
2. Boil 2 liters of water, put it in the above container and let it cool to 20C in the fridge(takes 2-3 hours)


3. Rack the homebrew into the keg, leaving the yeast with the trub into the fermenter
4. Add the cooled water into the fermenter, close the lid and swirl


5. Let the fermenter sit for 15-20 minutes. At this time you will be able to see the trub setling in the bottom, leaving the yeast in suspension on the top layer.

6. Carefully pour the top layer of water + yeast into your sanitised container(previously holding the cooled water), leaving the trub behind


8. Put the washed yeast into the fridge and let it sit there overnight for the yeast to settle at the bottom
9. You now have your washed yeast. Discard the top layer of water and store your yeast


You can keep your yeast in the fridge for 1-2 weeks, at which time you will have to use it.
If you are interested in storing your washed yeast in the freezer for long term usage, follow the below procedure:

1. Sanitize a container with which you can measure the volume of your washed yeast(such us your yeast starter flask) and another container that can hold the same volume
2. Tranfer you washed yeast to the above container to measure it. In my case my washed yeast was 250m. At this point i transfer the yeast to my other sanitised container, so i can use this container that is marked to prepare the glycerin solution
3. Plepare a 20 percent glycerin solution with the same volume as the washed yeast(250ml). Since the store bought glycerin is 99,5 percent, you will have to mix 4 parts of water with 1 part of glycerin. In my case this was 200 ml water with 50 ml glycerin, since my washed yeast was 250ml.

4. Mix this solution with the yeast and swirl for the glycerin to dissolve well into the yeast
5. For the next part i use sanitized 50 ml plastic containers, bought from the drug store. If you have other plastic containers that can hold similar quantity, sanitize them to use them

6. Slowly pour the yeast+glycerin solution in the 50 ml containers(10 plastic 50ml containers in my case)

7. Close the lids, mark the yeast and the date, and put the containers in a plastic container or cooler.

8. To prevent the yeast cells from freezing you can put isopropyl alchohol in your large container, or some gel packs. This will also help avoid thawing during frost free cycles.

9. Mr Malty says that thick washed yeast(only solids) contains 4 billion cells per ml. Since each of our 50ml containers has 25ml of thick yeast(before diluted with 25ml glycering solution), this is approximately 100 billion cells. When i take the yeast out of the freezer to make a starter, i calculate that is has 3 billion cells per ml, totaling in 75billion cells, just to be sure. I then create my starter using this calculation.</p>

Thanks for sharing the pictures. That really helps understand the process. How long does frozen yeast last? I've heard washed yeast can last 6-12 months.

Also, isn't the point of the glycerine so that the slurry doesn't freeze?

And if it were, I'd probably rather harvest from a starter to avoid all the other by products of a normal beer fermentation instead of harvesting from primary. But I'm sure your method works too

Hi Matt, i have read that it can last a year maybe more in the freezer. I believe in the fridge you will have to use it in 3-4 weeks.
Glycerin helps for the viability of the yeast, its a cryoprotectant.
When i first buy liquid yeast i either make a starter and use this yeast to store to the freezer, or if am planning to make a relatively simple beer(nothing too hoppy, or with spices) i may use that beer to grow the yeast cells numbers, and then wash the yeast and freeze it. Is this what you meant?

Hi Matt, i have read that it can last a year maybe more in the freezer. I believe in the fridge you will have to use it in 3-4 weeks.
Glycerin helps for the viability of the yeast, its a cryoprotectant.
When i first buy liquid yeast i either make a starter and use this yeast to store to the freezer, or if am planning to make a relatively simple beer(nothing too hoppy, or with spices) i may use that beer to grow the yeast cells numbers, and then wash the yeast and freeze it. Is this what you meant?

geobotsar said:

Hi Matt, i have read that it can last a year maybe more in the freezer. I believe in the fridge you will have to use it in 3-4 weeks.
Glycerin helps for the viability of the yeast, its a cryoprotectant.
When i first buy liquid yeast i either make a starter and use this yeast to store to the freezer, or if am planning to make a relatively simple beer(nothing too hoppy, or with spices) i may use that beer to grow the yeast cells numbers, and then wash the yeast and freeze it. Is this what you meant?

Click to expand...

This is what I meant by harvesting from a starter. You make a bigger starter than you'd need for your beer and then save the excess for later. I save my under the spent wort. But you could freeze it.

And on your longevity, I think you are confusing harvested yeast directly from the yeast cake at the bottom of the fermentor vs washed yeast. Here's what I've read:
- take a scoop of the yeast cake from the bottom of a fermentor and put it in a jar and store it in the fridge (don't rinse) - use within 2 weeks (this comes from the book Yeast).
- rinsed yeast using the method above (but not freezing) - lasts many months, up to a year or more. I know I've gone at least a few months with my rinsed yeast, but I always make a starter.
- frozen yeast - ?? (what I want to know).

Hey matt, i believe you are right. I had the wrong impression that rinsed yeast lasted in the fridge as long as the slurry and i have been freezing it. not sure though how long it could last in the freezer. This is a very good article on freezing yeast if you want to have a look: https://www.homebrewtalk.com/freezing-yeast.html

Thanks for putting this together - it was very helpful to me. A quick question in regards to the washed yeast pic - is the darker, smaller layer on top of the settled yeast good, or is that stuff bad, and the only thing you really want is the light, bright stuff on the very bottom? If so, do you try and pour as much as that off with the wort as possible, or is there another method for separating good from bad? Thanks,

The milky white stuff on the bottom is the yeast, but the other stuff isn't "bad". It's protein break and other stuff. When you're ready to use, pour off the liquid, but don't try to separate the stuff on the bottom and just swirl it up and pitch it.

Yep very well put Matt, thats what i do

This works just as well without adding water. There is nothing in the fermenter after racking that will present a problem for the yeast. In fact, it's actually the safest possible environment for storing yeast short of actual washing with acid. The yeast have built themselves a cozy nest that doesn't need to be disturbed. Simply leave enough beer to swirl into a slurry and pour it into your favorite sanitized container and stick it in the fridge. Easy as pie.

After a few weeks you might want to make a starter before using it. For longer term storage, decant the spent beer and replace it with fresh wort every 4-6 months.