Advice for Repitching a 9% ABV Yeast?

[maltoftheearth]

Last week I racked a Belgian Strong Ale (Wyeast 1388) off its yeast cake, washed two canning jars of yeast and set them in the fridge. The ale was around 9% ABV. It started at 1.076 and then I added 1.5 lbs of candi sugar three days into the ferment.

Next weekend I am brewing a honey sage ale, it will be around 1.060 for starting gravity. To add an additional challenge to this beer I want to use the same yeast as my Strong Ale. I have heard it is not recommended to repitch yeast from high gravity fermentations. Could someone help me with advice on how to increase my chances of using this yeast successfully?

I have an oxygen wand and a stir plate at my disposal. My thought was to do some small gravity starters (1.020 & 1.030) in half liter amounts of DME this week to get the yeast operating/accustomed to a lower gravity environment and propagate some more yeasties.

Thoughts?


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[BigFloyd]

The yeast issues from their involvement in a higher ABV ferment aren't something that you can "fix".

In the hostile environment of 9% ABV, the yeast cells suffer damage which causes petite mutations. Those mutations will likely be passed on to the subsequent generations of that colony. Their performance in the next batch would be questionable.

Get a fresh smack pack and make an appropriate sized starter.

 

[maltoftheearth]

So I don't make the same mistake in the future, what would you say is the max gravity/ABV to which a beer can be fermented before the yeast are no longer reclaimable?


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[BigFloyd]

I recall seeing something by Chris White that recommended not reusing if it fermented a beer higher than 6.5%.

 

[Calder]

You can re-use the yeast, and it will perform fine.

As noted earlier, high gravity will result in some mutation of the yeast, but I wouldn't expect you would notice it after 1 batch. If you make a habit of it, the yeast will start to exhibit obvious signs of changing.

Every time you use a yeast, and every time you harvest it, it changes. Unknowingly, you are selecting certain properties of the yeast due to your set-up, methods and recipes. Some things will change the yeast quicker, and fermenting high gravity beers is one of them.