[gmac]

I have a beer that is actively fermenting with WLP007 and it at high krausen right now.  If I wanted to brew another beer and "top crop" the yeast, is it as simple as just skimming the krausen and adding it directly to the wort or do I need to make a starter with the cropped yeast?  Both would be 5 gal batches.

[jmcamerlengo]

I reckon you'd need quite a bit of the stuff on top. I'd calculate it out using mr. malty to make sure its enough.  Also be aware that you're selectively harvesting the yeast the is on top which will be the least flocculent stuff, so the characteristics of the strain may change.

[repo]

I have a beer that is actively fermenting with WLP007 and it at high krausen right now.  If I wanted to brew another beer and "top crop" the yeast, is it as simple as just skimming the krausen and adding it directly to the wort or do I need to make a starter with the cropped yeast?  Both would be 5 gal batches.

Yes, but you'll want to skim off the "dirty" top part of the krausen and discard it, then collect the creamy white goodness for your pitch-straight in with the appropiate amount.  Guesstimating how much is something to take note of and after a few times you'll get pretty accurate with how much you'll need. At high krausen I would not worry at all about less flocculant yeast, or any characteristic changes after one harvest. That seems to be about skimming the top of the yeast cake.

[slarkin712]

It can be difficult to determine how much yeast you have.  I usually crop the yeast into a quart mason jar(sanitized) and then add boiled(and then cooled) water to fill up the jar.  I shake it up good and then loosen the lid a little to allow some gas to escape.  I put this in the fridge for a day or so to allow the yeast to settle.  I usually have a nice compact cake of yeast on the bottom of the jar.  From there you can estimate how much yeast you have.  And the viability will not be effected too much if you use it in a week or so.

[Pi]

What is the benefit of doing it this way? contamination would be my biggest concern. Is the risk worth the reward?

[slarkin712]

The benefits are that the when top cropping you get all healthy and clean yeast.  If you want to harvest yeast, this is a better way than rinsing the "dirty" yeast at the bottom of a fermentor.  You get nearly no trub and no dead yeast cells.  As far as contamination, to me this is no more riskier than taking a hydrometer sample from a bucket.  I can open a bucket, crop some yeast with a sanitized spoon and put it into a sanitized mason jar, and then close the bucket lid in two minutes or less.  As an aside, I find it easier to use a Burton Union type system as a yeast catcher/harvester.

[Pi]

Any way to harvest from a carboy?

[gmac]

I did it and it's working now. I scooped most of the white foam and just pitched directly. I had other yeast ready but I wanted to use it for something else so this is working fine for now.

[euge]

I did it and it's working now. I scooped most of the white foam and just pitched directly. I had other yeast ready but I wanted to use it for something else so this is working fine for now.

Works great doesn't it? You can take most of the krausen without fear. You won't disrupt the fermentation.

[Joe Sr.]

Any way to harvest from a carboy?

As mentioned above, you can use a burton union.  I'm not sure how else you would top crop from a carboy.

One of the gadgets issues of Zymurgy in the past two or three years had a DIY union (I think designed by Tom Schmidlin, IIRC). 

Also, here's one from BYO: http://www.byo.com/stories/projects-and-equipment/article/indices/20-build-it-yourself/354-build-a-burton-union-system-projects

[gmac]

I did it and it's working now. I scooped most of the white foam and just pitched directly. I had other yeast ready but I wanted to use it for something else so this is working fine for now.

Works great doesn't it? You can take most of the krausen without fear. You won't disrupt the fermentation.

Yeah, I figured the krausen wasn't actually doing much since it wasn't really in contact with the wort.  I expect that there was a lot more yeast in suspension than sitting on the top.

[tschmidlin]

Also, here's one from BYO: http://www.byo.com/stories/projects-and-equipment/article/indices/20-build-it-yourself/354-build-a-burton-union-system-projects

Thanks for posting this, I hadn't seen that before.

[Joe Sr.]

No sweat.

Was I correctly recalling that the Zymurgy Burton union was your gadget?

[tschmidlin]

No sweat.

Was I correctly recalling that the Zymurgy Burton union was your gadget?

Yes, it is more or less the same as the one you posted.  I prefer to think it was an independent idea, but it is totally possible I saw the BYO one when it came out and it was in my subconscious when I designed mine.

[nateo]

Doesn't Firestone use some variation on that?