yeast from a bottle?

[Arbe0]

I have seen posts on getting yeast from a bottle of beer, but I was wondering, hopefully not a stupid idea, of could you just pour the bottle of beer in a yeast starter to get the yeast from it? I guess the process would be to pour a bottle or 2 of beer into the flask and just start up the yeast starter. After I would think maybe make another yeast starter after that one is done to pump up the yeast. Do you think just the beer is enough or that it may need more sugars for the starter?

 

[MaxStout]

The beer from the bottle won't supply sugar for the yeast (it's already been consumed), so yes, you'll need to add fermentables to the starter. Using DME make some wort around 1.040 or so. There are some threads on this site that give info on stepping up starters with yeast from bottle-conditioned commercial beers. In a nutshell, you carefully pour off almost all the beer and leave the yeast with perhaps 1/2" of beer in the bottom. Then swirl it and pour the yeast into a sterilized container.

 

[hotbeer]

I think some or many of the big name commercial beers you buy might buy will have been pasteurized. So no yeast to cultivate. Smaller brewers probably less so. But I'm entirely uncertain to what extent modern brewers pasteurize regardless of big, small, import, export or otherwise. All of which I've read can be factors.

You also need to consider that some might have used a blend of different yeast. So then the question is will the ratios be correct that you obtain. Also, if the place used natural carbonation, did they use a bottling yeast that is different altogether from the yeast they fermented with. So again, you'll have multiple strains or types of yeast at unknown ratios to each other.

 

[z-bob]

You drink the bottle of beer; pour into a glass and leave a little more behind than usual. Swirl up the little bit that's left and pour it in your flask with some starter wort. Then maybe do the same thing with a second bottle of beer.

This works best with beers that are bottle-conditioned (and even then it might be the wrong yeast) or unfiltered and non-pasteurized. I've had very good luck with this with a couple of commercial wheat beers (Bell's Oberon and Schell's Hefeweizen)

 

[lumpher]

1 of the biggest concerns, even with unfiltered beer, is as @z-bob mentions. A lot of breweries, especially with the highly-vaunted (and deservedly so) Belgian Monk beers, use a different yeast to bottle-condition than they ferment with. You might THINK you're getting Westvleteren 12 yeast out of the bottle, but you're really probably getting a generic ale yeast, for example (not intended to be an exact statement, just an example).

 

[mac_1103]

You might THINK you're getting Westvleteren 12 yeast out of the bottle, but you're really probably getting a generic ale yeast

Or a generic wine yeast.

 

[worlddivides]

I've personally only ever done this with sours for the unique bacterial cultures used, and like others have said, whether we're talking yeast or bacteria, the bare minimum is that the beer has not been pasteurized. I only ever did it with beers where there was quite a bit of trub on the bottom of each bottle, and that's specifically what I used to get the culture for my own personal beer. Generally the more "craft" the brewery is, the less likely they are pasteurizing. The bigger the brewery, the more likely they are pasteurizing. That said, some small breweries also pasteurize, especially for styles that would benefit from it. But there are also a lot of big craft breweries that don't pasteurize, or at least they don't pasteurize all their beers. I've found this especially to be the case for some of the sour beers by some of the biggest craft breweries in the US where they write on the bottle that the beer will get more sour the longer you age it (which would obviously not be the case if it was pasteurized). And that's not even bringing up the issue that the bottle might have live yeast in it but live yeast for priming and not for fermentation.