Pure Culture From Dry Yeast

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mfdes

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I have often read that US-05 (US-56) from Fermentis is the same strain of yeast as Wyeast 1056. I have used both, though not 1056 for a while, and vaguely remember 1056 to have been slightly cleaner than US-05.
The explanation I've been given is that the drying process used to make any dry yeast inherently introduces contaminants. Is this still so? US-05 seems remarkably clean and stable compared to any dried yeast strains I tried a few years ago.
My ultimate question, I guess, is this: I culture my own yeasts as I have access to a laminar flow cabinet, an autoclave and a -70 degree ultrafreezer. If I plated US-05 in an agar plate and selected a single-cell colony, thereby growing a pure strain culture, would I have the same strain as Wyeast 1056? Is it worth it? I don't want to fork out the extra money to buy a pure culture of 1056 to culture if the strain I obtain from US-05 is identical.

Cheers,

MFS
 
Dry strains are not inherently contaminated any more apparently (or at least at minor levels compared to the contamination we all introduce at our homebrew level), though they used to be. I think the issue is not that the drying process introduces contaminants, but that the drying process is hard on yeast, and the precise yeast strain that was settled on by Fermentis to withstand this process is not identical to that of 1056 or WLP001 even though they came from the same source. So I'd say it's not worth it. If you have access to all that equipment, $15 to buy enough yeast to last a lifetime is not too much.

Anyway, that's my non-expert understanding, but to get a more expert answer, you could try emailing Fermentis and see what they say. They may well be forthcoming. Their site has all the details on the levels of bacteria etc present in their products as well. :)
 
Interesting enough though.
Why don't you ferment out a US-05 and then harvest the slurry.
If you wash the yeast and cultivate form there on in.
It is a bit beyond me but I am sure that it is possible.
I havent re-used US-05 slurry but had great experience with gathering w34/70 for reuse as using two satchet for its brew became costly.
 
Well, I plated US-05 onto agar and found that there are at least 2 types of yeast in there. There is a normal type that grows more slowly and forms typical arborescent colonies (I mean the daughter cells come out as two at the end of the mother cell and you get tree-like colonies), and another smaller one that grows really fast and forms amorphous white colonies.

The yeast I started with had been re-packaged by my local homebrew shop, so they may have cross-contaminated. Or perhaps the small-cell colonies are petit mutants.

I'd have to either isolate both into pure strains and ferment some starter to see what happens, or just give up now and buy some Wyeast 1056 or WLP001 to establish a pure culture from.

MFS.
 
That's very interesting, MFS. Sounds like it'd be worth while seeing what you get from those two yeasts out of interest. As I said before, I'm sure Fermentis will respond to an email about what you are seeing there. Certainly worth a go IMO. Anyway, like to know how it goes.
 
I'd have to either isolate both into pure strains and ferment some starter to see what happens.
MFS.

Isolate both into pure strains and ferment 2 beers from them.
You may have the new Tassie / French / Pacman liked strain. :D
If one is good and the other no so just feed it to your mates over summer. :beerbang:

- Luke
 
Quick update:

The small cell colonies have settled down to produce full-size cells. Probably take off rapidly into small cells then fill up later.

Now have a pure strain to play with. It'll be interesting to see if it's a bit cleaner than US-05 when grown as a conventional liquid yeast starter.

MFS
 
A recentish issue of Zymurgy had a comparison (done as I remember on a commercial micro brewer scale) of WLP001, 1056 and US-05 (US-56) all of which are apparently the same same strain and a strain that came from Ballantynes IPA.
The results were remarkably close..as they should be.
There is no reason in 2007 that a quality dried yeast such as Fermentis produces be every bit as viable and every bit contamination free ..out of the packet..as a liquid yeast..out of the vial or pack. There may be a problem in this case
The yeast I started with had been re-packaged by my local homebrew shop, so they may have cross-contaminated.
but that is out of control of both the manufacturer and the home brewer. Now if the re-packaging were done under the conditions that you have available then you could be reasonably certain of an uncontaminated strain, but if the HBS simply spooned (same spoon) approx 11g portions into zip lock bags in the shop while a few brews are brewing away, a bit of beer has spilt here and there, there's a bit of malt extract lying around..hygenic perhaps but a yaest lab..???
Liquid yaests have the advantage of diversity and I have not bought a dried yeast for probably 5 years.
But..to your original question...US-05 would seem to be the same strain as WLP001 and 1056 so pick your colonies well and you have it..

K
 
I seem to hear mixed reports.

Some say it's indeed the same yeast and differences stem mainly from the way the drying process affects the cell physiology in the immediate aftermath. If this is the case then a pure strain isolated from a single cell and grown in the conventional way should produce the same effect.

Others say the strain picked by Fermentis is not the same (though similar) as WLP001 and WY1056, and was chosen for its ability to cope with the drying process.

Will do an APA on the lighter side pretty soon with it and report on the results.

MFS.
 
Hi MFS,

Just wondering if you brewed the APA you mention and what results you found.

What are others thought on the difference / similarities of US-05 and 1056?

Cheers BDB
 
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