Quick yeast starter question...

Gizmo · 03-30-2009, 01:36 AM

Hey. I made a yeast starter friday, and was planning on making beer tonight (sunday) but my schedule changed and I can't brew for another day or two. I had already put it in the fridge to let the yeast sink to the bottom and pour off the beer before pitching.

My question is: since I'm not brewing until mon or tues, and the yeast hasn't finished propogating anyway, would it hurt anything to bring it from the fridge back up to room temp to propogate for another day, then re-refrigerate it again mon or tues, to let the yeast sink back down, or would the temperature swings freak the yeast out too much?
Thanks (p.s. or should I just leave it in the fridge @ 34-38 degrees and it propagate slowly for another 24-48 hrs that way; there is still propogation going on in the fridge right now, yeast moving around, etc) and I'm using WLP001 (white labs) if that matters

**beerthirty** · 03-30-2009, 02:00 AM

I would leave it in the fridge. If they are still feeding they wont go dormant on you and cause a longer lag time.

Gizmo · 03-30-2009, 02:16 AM

Ok, so you don't think I risk underpitching because it hasn't propogated fully? Well, I'm not sure actually, normally I go at least 48 hrs before refrigeration but this one was at 74-78 degrees for about 42 hrs before I stuck it in the fridge. How long does it take anyway? I've heard different numbers from different people...

**beerthirty** · 03-30-2009, 02:49 AM

And I'll give you different #s too.

Usually about 24 hours at room temp, but I've gone as little as 12 and pitched at hi krasuen, and as long as letting the yeast consume all the sugars and going dormant in the fridge then warming up to room temp 2 weeks later and pitching. Pitching at hi krasuen allows the yeast to be at their most active so the propagate faster in the wort. warming up a fully fermented starter gives more cells to work with but they have to be waken up. I havent decided which works best, but both work and make great beer.

**JuanKenobi** · 03-30-2009, 03:08 AM

+1 to pitching at high krausen. I get great results both ways too tho. I think that in the case of old/expired yeast it might be better to let the starter ferment out to ensure maximum population.

Gizmo · 03-30-2009, 03:15 AM

Ok, so, um a few more questions if that's ok...

1. What is "high krausen"? When the yeast is most active, meaning 'before' it has consumed all the sugars and dropped out of suspension at room temp?

2. Can I still refrigerate, dump beer from top of starter, warm to room temp (6-8 hrs), and pitch slurry when it's at high krausen, or will that risk dumping yeast?

3. And... how do you tell when a starter is at "high krausen"

4. Starters will last two weeks in the fridge? (if so then, Yippee!) (I thought it was only 2-4 days)

(sorry, trying to learn everything I can, I'm on my 3rd batch, and so far so good, my 1st brew tasted great)

(starter is back in the fridge, still propogating, yeast "plooping up" from the bottom every so often like a lava lamp)

**JuanKenobi** · 03-30-2009, 03:23 AM

Krausen is the head that forms during the most active part of fermentation. You probably saw this on you're other batches if you fermented in a carboy. Some starters might not ever even form one, but I've found that when I use fresh yeast it usually does. As Beerthirty said, pitching at high krausen lets you know that the yeast is at it's most active. You'll find differing opinions about when to pitch starters. You've got it though. Just leave that starter in the fridge until you need it then pull it out (6-8 hours ahead of time like you say), decant the beer and pitch the slurry. No worries.

Gizmo · 03-30-2009, 03:37 AM

Cool deal. Yeah, I've definately seen krausen on full batches, some yeasts more than others. With a yeast starter the only thing close to krausen would I guess be around 18-24 hrs into it. When I "swirl" it, and theres an immediate huge head that forms, releasing a lot of Co2, then subsides for the most part after sitting for a few minutes. I use a plastic jug and "intermittent shaking" (as per mr malty) now, but will eventually work up to a stir plate

Thanks a lot, I haven't quite gotten past the "making beer without racking my nerves" phase yet, but each brew is getting progressively easier, and less messy, which makes the wife happy (1st brew looked like a bomb went off in the kitchen)

Oh btw, how long do you usually cool your starter before decanting the beer from the top, I usually wait around 24-48 hrs, is that enough or am I loosing too much yeast that way? (should I wait until the liquid is clear above the yeast?)

**JuanKenobi** · 03-30-2009, 03:46 AM

I also use the intermittent shake method right now. 24 hours in the fridge should be fine. I have decanted starters that I chilled for only 12 hours for one reason or another and they have always been fine. As long as you're not grossly underpitching everything will be okay.

Gizmo · 03-30-2009, 03:58 AM

Cool ok, I was just asking cause I don't think I've ever decanted perfectly "clear" beer off the top of a yeast starter, but my batches have turned out fine so far, and every batch gets closer to my predicted final gravity so I'm obviously doing something right (last FG was 1 point over target).

Thanks a lot man, I'll be brewing yet again probably tomorrow (yay!). I need more carboys though, this is quickly turning into a serious (and tasty) hobby