Harvesting yest from difficult commercial beers

Problem:
Stone IPA in 12-oz bottles is very clear and almost seems filtered (is it?). I attempted to get some sediment to streak on wort/agar plates, but did not have much optimism.

Procedure:
Here's what I think may be a different approach: I ran about 6 ounces of the ale through a .45 micrometer millipore filter using a Nalgene analytical filter and put the filter on a spare plate.

Results:
1)I streaked 6 plates with the dregs from the bottle and got one or two cells per plate, maximum. I guess that's enough... but not a great result.

2)The filter has at least 100 colonies on it.

Conclusion:
I think this might work for any beer that has a very low or nearly absent yeast population. I would suggest this for any attempt to farm a strain that has yielded poor results using the standard method.

Please share any comments or questions.

apeltes said:

Problem:
Conclusion:
I think this might work for any beer that has a very low or nearly absent yeast population. I would suggest this for any attempt to farm a strain that has yielded poor results using the standard method.

Please share any comments or questions.

Click to expand...

Have any pics? I don't understand about the "colonies on the filter part".

Does stone pasteurize or filter? If the former, you're going to have a hell of a time getting dead yeast to grow.

Basically it seems apeltes took some filterpaper with .45 micron holes in it, poured the IPA through the filterpaper into some other bucket and collected. He then proceeded to grow the yeast on the filter paper, by placing them on agarose gel or in a media of some sort. After a set period of time, about 100 yeast colonies formed on the filter paper.

I will preface this with I haven't done a lot of cell culture work though. I don't see anything wrong with it....I'm a little curious as to what you helped promote the growth with though, more for my own sake.

I think that's a great job, apeltes and welcome to the forum. It looks like filtering is the way to go. Are you going to try to culture any of these colonies to brew with? These yeast have been through a lot at this point. You might consider culturing multiple colonies and looking at them under the microscope just to get an idea of what kind of shape they're in before choosing one to brew with.

celts said:

He then proceeded to grow the yeast on the filter paper, by placing them on agarose gel or in a media of some sort.

Click to expand...

Thanks for the clarification. I didn't catch that the filter paper was on a "spare plate", so I was wondering why yeast would flourish on just filter paper.

Thanks for the feedback. Here's more detail:

I used petri dishes and media containing 1.020 SG wort (distilled water and DME) and 1.5% agar.

After running the beer through the filter, I placed the filter directly on the media in one of the petri dishes. For the other dishes, I used a sterile swab dipped in the dregs.

The swabbed plates grew one or two colonies each, but I got 50+ colonies on the filter.

I innoculated 6 slants from the colonies on the filter, and all are growing well. I'm stepping one of them up to brew a Stone IPA clone later this week.

I do have photos, but I'm not a paying member of this forum. I could e-mail them to anyone interested unless there's another way.

Just upload the pictures to flickr or another file sharing network right click the photo and click copy link location then clicky the insert image icon (the yellow one with majestic mountains) and paste the link. Now you can picture whore all you want. Oh and good form on the cultivation. I really do want to see what you've come up with.

Stone does not Pasteurize, WTF take it up with them, bring an army for a Q like that