Re-using yeast after high-gravity fermentation?

Hey all,

I am in the middle of fermenting the Austin Homebrew Chimay Grande Reserve clone, and one it is done I'm going to have a bunch of used WLP500 yeast. Since it is not the cheapest yeast (especially since I pitched two vials), I was thinking about re-using it, possibly with another batch of the chimay, possibly with something else.

I've read plenty of times in this forum that sometimes it is OK to simply throw some new wort on top of the yeast cake after racking to secondary. However, then I found this thread that makes me hesitate.

My OG was 1.086, so this is definitely a high-gravity brew. So, is that WLP500 spent? Can I use it again for another batch of the same, or should I go with a lower-gravity? Any suggestions for what might be tasty?

Thanks!

I use a more simple and practical method of basically putting a few tablespoons of trub from the secondary into in a bottle with some DME and yeast nutrient then putting it in the fridge.

1. Buy specialty yeast that you want to use continuously.
2. Make beer with that yeast.
3. After racking, transfer about five tablespoons of trub/yeast at the bottom of the primary or secondary fermenter to a sanitized plastic soda bottle.
4. Add water to the top of that bottle.
5. Add a few tablespoons of DME (or sugar) and a pinch of yeast nutrient.
6. Cap, shake and refridgerate.
7. When making a starter, extract only the upper, lighter-colored sediment layer as that is most likely pure yeast.

You probably have a lot of dead yeast in there as well as other trub products.

You can use the yeast to create a start or a mother, and brew on from there, but might not want to use all of that yeast trub directly.

If you like that yeast strain, you might want to consider making a mother with some of the yeast trub (secondary is better for this), or make it from about a Tbs of yeast from a new vial next time you by one.

Here is a thread I discuss making yeast mothers:

https://www.homebrewtalk.com/f163/canning-starter-wort-145763/

Until now, I've always used dry yeast. Now that I've paid the price (literally) for liquid yeast, I understand why people go through the trouble of making mothers and starters and such. I just need to take the plunge. I'm starting to brew so often now that it really makes sense for me to stop being scared of liquid yeast and starters. I'll probably leave the "what's the difference between a mother and a starter" question for another thread -- thanks so much for your advice. (Also -- good tip about using the trub from the secondary rather than the primary; makes perfect sense since it is more likely to be mostly yeast)

As always, HBT rocks.

I'd not reuse any yeast that has gone through a fermentation of over 1.060 personally.

flyangler18 said:

I'd not reuse any yeast that has gone through a fermentation of over 1.060 personally.

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Yeah, I'm hearing a lot of that. I think what I need to do is buy more liquid yeast and immediately make a mother from that. Then I can use the yeast once each, taking from the mother each time.

What changes between yeast cultures that have fermented normally and cultures that have femented higher gravity worts? You still have live and genetically identical yeast.

amercuric said:

What changes between yeast cultures that have fermented normally and cultures that have femented higher gravity worts? You still have live and genetically identical yeast.

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I think it is the unknown factor really. If you are looking to make a championship beer unknown factors are anathema. The higher gravity "could" lead to a more stressful environment for the yeast, and thereby increasing the rate of genetic mutation.

Personally I think this is a greater fear than the reality justifies. If you need the yeast for a competition or something, use a fresh vial. Otherwise what is really going to happen? If the yeast was too stressed out, the beer might be slightly off style. If the beer tastes off style don't use the yeast. If the beer tastes fine, then chances are the yeast is OK too.

The main thing is use sanitary procedures. Don't let Lacto into your stuff. Rack and bottle relatively quickly to prevent Brettanomyces from getting in it too. I think I read somewhere the B. will get in to open fermentation after about 6 months. If your not in that category I wouldn't worry.

slouch said:

The main thing is use sanitary procedures. Don't let Lacto into your stuff. Rack and bottle relatively quickly to prevent Brettanomyces from getting in it too. I think I read somewhere the B. will get in to open fermentation after about 6 months. If your not in that category I wouldn't worry.

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Agreed. I also made a thread about it here: https://www.homebrewtalk.com/f128/v...east-has-fermented-high-gravity-worts-147117/

I would rinse the yeast and do a starter from a small amount of it to grow up some non-stressed and healthy cells. It really isn't hard to do and the slight effort is does require, I think, is justified rather than risking off flavored beer.

Not sure if I am over paranoid, but when I rinse my yeast, and there is no protective alcohol layer, I use a dilute San Star solution to help keep out/kill any bacteria.

I have recently made a rookie mistake and pitched a low gravity wort onto a high gravity yeast cake. Here is the story. Any comments from the more experienced users is greatly appreciated.

About a month ago I brewed a 1.082 OG winter ale using white labs CALIFORNIA ALE yeast (made a starter). One week ago I transferred the winter ale to the secondary and put a 1.054 OG pale ale wort onto the yeast cake... Fermentation took off almost immediately and slowed down two days ago. This morning I transferred the pale ale into the secondary, took a hydrometer reading, and tasted it... VERY VERY fruity.

While my beer isn't finished yet and could possibly improve, I am very disappointed. I can't help but think the fruity flavors are from over pitching, or from yeast cell death.

Bottom line: I will never make that mistake ever again. I think I will even be hesitant to pitch a high gravity wort onto a lower gravity yeast cake.

I hope this post might prevent some other rookie from making the same mistake.

-Cheers-