Harvesting yeast

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Well-Known Member
Dec 7, 2004
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Williston, ND
Hello. I just picked up 4-pack of Duvel from my local liquor store. Since Duvel is bottle conditioned, there's a layer of yeast at the bottom of the bottles. Is there a way I can harvest this yeast to use in my own beer, and grow enough to make it pitchable? Or would that not be a good idea?
From what I understand, this should be totally possible. I think I remember something from the Papazian's Joy about attaching a balloon to the neck of a bottle, after flame sterilizing the lip, and adding some boiled wort for the yeast to work on.

I recently tried a variation of this with some bottles of Obsidian stout (also bottle conditioned), where I poured out (and drank) most of the liquid from the bottles, leaving a 1/4 inch or so in the bottom. I swished this around in there to loosen any yeast sediment their might have been, and poured it into my yeast starter jar (with an airlock) with some boiled corn sugar, molases, and yeast nutrient. It just sat their for a few days, as I assume the yeast in commercial brews has probably gone dormant. Finaly I saw some bubbling and signs of life. I haven't used the starter yet (I mainly wanted to see if I could get the yeast to come alive), and I am not sure if it has enough active yeast to make a good starter anyway. The wort looks pretty cloudy, there are a few bubbles around the edge of the liquid's surface, and their is a fair amount of sediment at the bottom of the jar. Does anybody know how one can tell the strength and purity of this sort of starter? I sniffed at the airlock and it smells pretty much like any batch of beer in fermentation (without hop smell of course) and there isn't any obviously nasty stuff on the surface. Is there a better way that I could have done this (for both me and Seven77's benefit)? D.
I've done this a bunch. It seems to take about a six-pack's worth to get a good yeast pitch to add to a starter. I've had success doing it by just gathering the last little bit of each bottle all schwirled up and then poured all of them into one of the bottles, popped the cap on it and stuck it in the fridge and took it home after the party :D

Of course, the more careful you are, the better, but I have had success every time, sometimes using pretty sloppy technique. If I were to do it right, I guess I'd:
1 - Sanitize a small jar or something.
2 - pour each beer as I open it into a glass, schwirl the last bit, flame the lip of the bottle, and dump yeasty beer into said jar
3 - collect a six pack's worth of yeast and seal jar
4 - make starter

Most of the commercial beer yeasts are available through White Labs or Wyeast, but for rare, weird ones like Belgians, or just for the fun of it, harvesting yeast is a hoot.

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