Washed yeast generations

[callback79]

Hi,

Just want to be sure if I'm understanding correctly how washed yeast generation are calculated.

Let's say I can use yeast for 5 generations, using the "standard 4 jars" each times I'm washing the yeast.

Gen 1 - First generation gives 4 jars. (4 jars)

Gen 2 - Those 4 jars gives 4 jars each (16 jars)

Gen 3 - Those 16 jars gives 4 jars each (64 jars)

Gen 4 - Those 64 jars gives 4 jars each (256 jars)

Gen 5 - Those 256 jars gives 4 jars each (1024 jars)

So my questions:

1. Is it really how it is calculated ?
2. For beer under 1.060, do we really need only one jar of washed yeast for a 5 gal batch ? (With starter of course)

 

[discokid2k]

Im not sure about the formula but I can tell you that with most brews under 1.060, one jar with a 1l starter does just fine with me. I have seen cleaner brews, shorter lag times, and great yeast flavors with 4+ generation use. I have been stock piling my yeast for over a year and havent had an issue yet. I have seen very subtle evolutions of flavor but that could just as easily have come from the ingredients too. I have paid more attention to the starter temps (ale or lager) and storing temps (about 39*F). If I have to use my mini fridge for a lager fermentation with warmer temps, I move them inside my house fridge until I can drop the mini fridge back down to lager temps. I have 60+ jars currently but I took it a step further and down sized the jars so I have more storage space. I go from 1 gal, to 1 liter(3 1 l bottles per 5gal batch usually), to 12 oz jars and then finally condensed into 3oz jars, which can be bought in the canning sections of most grocery stores. Have had zero negative side effects thus far and have easily saved over $100 not buying yeast. Go me

 

[ReverseApacheMaster]

Yes those calculations are correct.

You will lose viability of the washed yeast with age so don't automatically assume one jar will always provide enough healthy yeast so you only need a one liter starter. Since you will always end up with more yeast than you can ever use if you keep washing you'll end up with a lot of old yeast in the fridge or throwing a lot out. The best thing to do is to wash the first generation and freeze all but one jar (there is a frozen yeast bank thread explaining how) and you can wash that line of yeast as much as you want and when you run through it all, go back to your frozen source and start again. It cuts down the amount of storage and old yeast by a lot.

 

[callback79]

Awesome.

I forgot to ask if washing yeast can be done with almost every kind of yeast.

More precisely, I would like to wash Wyest 3944 (Belgian Witbier) and 2565 (Kölsch). The last one seems to be a little trickier since it doesn't settle down pretty well.

Thanks for your answers guys.

 

[discokid2k]

Yes those calculations are correct.

You will lose viability of the washed yeast with age so don't automatically assume one jar will always provide enough healthy yeast so you only need a one liter starter. Since you will always end up with more yeast than you can ever use if you keep washing you'll end up with a lot of old yeast in the fridge or throwing a lot out. The best thing to do is to wash the first generation and freeze all but one jar (there is a frozen yeast bank thread explaining how) and you can wash that line of yeast as much as you want and when you run through it all, go back to your frozen source and start again. It cuts down the amount of storage and old yeast by a lot.

+1 on the frozen yeast bank! I have a new project and it seems pretty easy.

I am currently on gen2 of wyeast 2575 so I dont see why you couldnt do the 2565. Not familiar with the 3944 but as mentioned, I have had a lot of success. I can tell you that you end up with a lot of jars though so ReverseApacheMaster may have suggested the perfect solution. I use a lot of my yeast pretty quickly lately as I am making smaller test batches. I get to brew more and test out different flavors. winwin. My oldest yeast I have is close to a year, havent had to throw any out yet.