Korean yeast

[Kunkemonster]

Anybody know if there are any strains of yeast sourced from Korea? I saw a post on homebrewtalk about a guy harvesting wild yeast from juniper berries. I saw a tree full of yeast covered juniper berries yesterday and I thought about experimenting. Have any of you had success with wild yeast here? I might buy a few pounds of malt extract and give it a go.

[gordsellar]

Did you ever try this? I spent the last six weeks writing, writing, writing -- I was doing a writeathon and also trying to beat some deadlines, so I've missed a lot here -- but if you did, I'd love to hear about it.

Also, juniper trees? Where? I have been thinking about harvesting some branches (with berries on them) to give the Chinese juniper a go, in terms of making some kind of Koreanized equivalent for the sahti recipe in Randy Mosher's Radical Brewing, but I haven't noticed any juniper trees in my area. (I was hoping some would be growing on the mountain out back, but there aren't any I can find.)

If you'd like the recipe, I can bang out a copy for you, but I'll note that even with fresh juniper berries on hand, the yeast used in sahti is... bread yeast! (And since a degree of sourness is in the style, sometimes a little lacto or use sourdough starter.) But I've also seen sahti recipes online that, while slightly more experimental than Mosher's -- no boiling! -- happen to just use regular ale yeast.

Personally, I'd probably use the regular ale yeast too, maybe just spiking it (or krausening?) with a small amount of purposefully soured, unfermented wort to control the degree of sourness.

Ah well... I'd love to get my hands on some juniper this fall, so I could try do up a slightly less-experimental sahti. But I won't be brewing for another few weeks, I think -- too much other crap to get done.

[Kunkemonster]

I saw them on base; though I'm not 100% they are juniper trees. I haven't got around to making it. I don't have any DME on hand. I will probably do the experiment in the fall, when it gets cooler and I place another order.

[gordsellar]

Ah, well... I'm going to continue my search (er, for juniper bushes I mean). By the way, I ran across a great thread about brewing with yeast harvested from juniper berries! Now I'm eager to try it... there's something appealing about the idea of brewing a sahti with yeast harvested from juniper berries.

(Likewise I can't help but wonder if there's usable yeast on persimmons. Another experiment to try this fall, I guess...)

EDIT: besides clarifying that I mean juniper -- there are some photos on the thread that might help you identify whether you're really seeing juniper bushes, but they come in a huge variety -- I'd previously only seen some that were just smaller bushes, but in the backyard of a friend I visited last summer, the juniper there was a huge tree! I imagine you'd be dealing with Chinese juniper, though... maybe a Google search will bring you a pic that can help you confirm... though, then again, if you're just harvesting yeast, it may not matter -- yeast on one berry and yeast on another are just as well...

[Kunkemonster]

Yeah that's the thread I saw as well. I don't think it really matters what kind of juniper it is as long as there is plenty of yeast.

[jdog2050]

I would probably be very wary of trying this in Seoul, or any part of the peninsula that gets hit hard with the Yellow Dust from China.

[gordsellar]

Hmmm... I don't think the Yellow Dust would make such a big difference in terms of yeast harvesting, would it? I mean, you'd want to wash the yeast (to get rid of all the other crap that accumulates in the dust), but it's not as if the heavy metals and toxins from the Chinese smog are going to start multiplying the way the yeast does. I'd be surprised if you were exposed to more of that stuff from anything brewed with harvested yeast than, say, 3 minutes outside on a Yellow-Dusty day.

The interesting question, though, would be what kind of selection pressures would come into play for the yeast here. I wouldn't be surprised if the yeast you did manage to harvest was hardier, but it might also have other weird properties. (More or less flocculation, more of less weird esters or off-flavors, etc.) It'd be interesting to experiment with that, of course working with 1 gallon batches at first.

[jdog2050]

That's the thing dude. Yellow dust aint just dust. It's got loads of bacteria, pollen, and even particles of human feces.

[gordsellar]

True -- though... feces? Huh? How does that get into the yellow dust? I'm not disagreeing, but that's bizarre and I've never heard that before.

But it seems to me that even so, the amount of that bad stuff that's in any sample of dust one collects for yeast harvesting is going to be minimal, and if you're careful in how you control the pH and nutrient content of the growing solution, it will not (in terms of bacteria) or cannot (in terms of pollen and feces) propagate like the yeast does. I doubt it's any more or less than the amount of bacteria, pollen, or feces in other stuff grown in Korea. There's pus in milk, and there's almost certainly trace amounts of cow feces in every burger you eat. That's just for starters... we could talk about juice and other things too...

So you harvest and (under controlled conditions) grow the yeast, and then you "wash" it.

If you're really, really worried about the yellow dust, though, you could get agar and do slants, and then grow your yeast from that -- it would minimize even the slightest amount of extraneous material. I think that's probably overkill, but it's an option.

And by this time of year, hasn't it rained enough that the yellow dust has mostly washed off anything one might use in terms of wild harvest? I'm asking, not telling... I kinda just figured it would have by now...

[Kunkemonster]

I agree with Gord, if I do this I will definitely wash it once or twice before brewing anything with it.