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General Category => Yeast and Fermentation => Topic started by: beersabound on July 08, 2012, 07:11:42 PM

Title: Help my Kolsch finish fermenting
Post by: beersabound on July 08, 2012, 07:11:42 PM
I brewed a Kolsch three weeks ago. Mash temp was 148F. I used WLP 029 and made a starter.  Ferm temp has been between 58-62.  After one week, it was at 1.014.  Now it sits at 1.013.  I'd like it to drop to 1.008 - 1.010. 

Any ideas on how to get it to drop a little more? Raise the temp? Pitch more yeast? Wait it out?

Thanks, Tim
Title: Re: Help my Kolsch finish fermenting
Post by: tygo on July 08, 2012, 07:52:53 PM
What was your grist?  OG?
Title: Re: Help my Kolsch finish fermenting
Post by: Mark G on July 08, 2012, 07:55:25 PM
You can try raising the temp into the mid 60s and gently swirl the fermentor. You might get a couple more points out of it, but odds are, after three weeks, it's just done. How does it taste? What was your recipe?
Title: Re: Help my Kolsch finish fermenting
Post by: Jimmy K on July 08, 2012, 08:04:23 PM
What Mark said.
Title: Re: Help my Kolsch finish fermenting
Post by: beersabound on July 08, 2012, 08:36:05 PM
OG was 1.047

Grist was 90% Pils and 10% wheat malt.

It tastes okay but it is a touch sweet.

Thanks for the replies.  I think I'll raise the temp on it.

Title: Re: Help my Kolsch finish fermenting
Post by: nateo on July 08, 2012, 09:41:53 PM
I don't think you'll hurt it going up to room temp with it, though @ 1.013 there's a good chance it's done.
Title: Re: Help my Kolsch finish fermenting
Post by: Jimmy K on July 08, 2012, 10:57:54 PM
OG was 1.047

1.047 - 1.013 is 73% attenuation - within, though at the low end, of the range for that yeast.  White Labs does say WLP029 "does not ferment well below 62" so that may not have helped. If you warm it to the high 60's and stir the yeast up it may help - if not it may be the recipe/mash and not the yeast.
Title: Re: Help my Kolsch finish fermenting
Post by: tygo on July 09, 2012, 01:37:43 AM
I think you're probably done.  Last one I did with this yeast went from 1.049 - 1.011.  I just brewed up a kolsch with this yeast again today so we'll see how this one does but I'm expecting similar results.  I ferment at 58F.

Warming it up and rousing it won't hurt, but I'm going to guess you're not going to get much more out of it.

You said you made a starter...how big?
Title: Re: Help my Kolsch finish fermenting
Post by: newrocset on July 09, 2012, 02:00:27 AM
I have continuous problems with attenuation and I'm looking at starter sizes and mash temps to resolve it.  How big was your starter?  In my opinion a Kolsch needs to be fermented at a very low ale temp, that being said, you need at least a 1 gallon starter for the yeast to eat all those sugars and with a 90% pils malt in your bill, you are likely going to get a load of fermentable sugars rather than a bunch of non-fermentable dextrins - so I'm guessing, even though you made a starter, it wasn't big enough - did you use a stir plate? did you check manufacture date of your yeast?  I had the exact same problem as you w/the Kolsch I did a few months ago.

Here's a case I had with my last batch:
Brewed a 10gal Brown Porter OG 1.060
5 gallons on top of a carboy of ESB yeast from which I just racked off a standard ordinary bitter: it started fermenting the minute the wort hit the yeast, and took one week to make a nice dry 1.008 (I think, though could've been lower) - anyway it fermented all the fermentable sugars and left some pleasant sweet dextrins.
Other 5 gallons on a 1/2 gallon starter of London Ale Yeast (the stuff that's supposed to ferment out pretty well): ended in 3 weeks w/a 1.020 FG....tasty, and actually closer to a brown porter, but too sweet for me.

Moral of the story: I pitched my wort on a giant active yeast cake and it fermented fully, whereas the 1/2 gallon starter just didn't cut the muster....
Title: Re: Help my Kolsch finish fermenting
Post by: beersabound on July 09, 2012, 02:28:08 AM
I used mr. malty for a hybrid.  It was a 5.5 liter starter with two vials and the vials were less than a week old.

I figure it is done but was hoping it would be drier.  No biggie.  Just something to focus on for the next batch.
Title: Re: Help my Kolsch finish fermenting
Post by: tygo on July 09, 2012, 02:32:16 AM
Well, that should have been plenty of yeast then.

Are you sure about your mash temp?  You have a good thermometer?

How did you aerate the wort?
Title: Re: Help my Kolsch finish fermenting
Post by: nateo on July 09, 2012, 02:37:07 AM
I have continuous problems with attenuation and I'm looking at starter sizes and mash temps to resolve it. 

There are two philosophies for yeast performance. Beer guys only really care about mash temp and yeast count. Wine guys care a lot more about the yeast's needs throughout fermentation, and pitch at much lower rates for much higher gravity than you'd want for brewing. Wort and must aren't the same, but it's something to think about.

I try to rouse my yeast every day until I hit terminal gravity. It keep the yeast in suspension and blows off CO2. CO2 in solution = carbonic acid. During fermentation, when lots of CO2 is being produced, the pH can drop low enough to inhibit the yeast. If you pitch enough yeast, it can plow through anyway. This effect is exaggerated in mead and wine fermentations, but I've noticed similar effects when fermenting wort.
Title: Re: Help my Kolsch finish fermenting
Post by: udubdawg on July 09, 2012, 02:49:43 AM
FWIW, made my first Kolsch last year.  148F, WLP 029, 1.047, just like yours.
also finished at 1.013.  I carbed it a bit higher than usual to lighten it up.  It won three silver medals, always beaten by another style.
subsequent tweaked batches have no trouble getting to 1.008, but I think I still prefer that first one. 
I also feel this yeast performs great at higher temps like 65-67.  Love that slight white wine grape fruitiness with just a hint of tartness.

cheers--
--Michael
Title: Re: Help my Kolsch finish fermenting
Post by: beersabound on July 09, 2012, 04:48:11 AM
Well, that should have been plenty of yeast then.

Are you sure about your mash temp?  You have a good thermometer?

How did you aerate the wort?

I am pretty sure about the mash temp.  I calibrate the thermometer before each brew.  Any recommendations on a bullet proof, accurate thermometer?

I aerate with pure O2 and one of those stainless 2.0 micron thingies. 

I use the same O2 procedure and thermometer for all brews and usually get pretty close for expected terminal gravities.  I am guessing it has to do with ferm temp.  But, first hybrid for me and I don't make lagers so it's a new adventure of sorts.
Title: Re: Help my Kolsch finish fermenting
Post by: tygo on July 09, 2012, 12:33:01 PM

I am pretty sure about the mash temp.  I calibrate the thermometer before each brew.  Any recommendations on a bullet proof, accurate thermometer?


I like this one:  http://www.thermoworks.com/products/thermapen/

It's pricey but it's durable, accurate, and reliable.
Title: Help my Kolsch finish fermenting
Post by: majorvices on July 09, 2012, 02:05:23 PM
I've said it many times fore, that strain will stall if you don't warm it up over 62 degrees near the end.

But, realistically, I don't think you could notice much difference between 1.013 and, say, 1.011. It will taste less sweet when it is carbonated. Carb it up and drink it!
Title: Re: Help my Kolsch finish fermenting
Post by: kylekohlmorgen on July 09, 2012, 06:24:45 PM
I had problems with Wyeast's Kolsch yeast (2565) the first time I used it. Underattenuated with a bit of acetylaldehyde.

I make a starter for this yeast and pitch closer to lager temps. I'll start around 62F, but I do a diacetyl rest up to 65F to make sure it finishes completely and cleans up all the fermentation intermediates.

To be safe, I'll do this for any beer that doesn't have much to hide behind (kolsch, cream ale, lagers, even low-alpha pales).

Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 09, 2012, 07:15:28 PM
You could do a forced fermentation test to see if it's done or not.  Take a sample, put it on a stir plate, warm it up, give it some fresh well-attenuating yeast (dry is ok), and see if the gravity changes after a day or two.  If you watched the Brew Masters TV show, they basically showed their lab tech doing it when a batch stalled.

Might be worth figuring this out before trying to "fix" a beer that might not be broken.  If the beer is at its limit of fermentability, about all you can do to lower the FG is to add water or add something that can eat what's left in your beer (e.g., Brett -- but that would make a pretty crappy Kolsch).

I normally step-mash my Kolsches; that might give you some additional fermentability in future batches.  You did add some wheat; that might need some help being fully reduced to fermentable sugars.

It could taste sweet to you because of low IBUs or low carbonation.  Malt, unbalanced by hops, tastes malty but many pick it up as sweet.  More carbonation lightens the impression of body and can add a bit of a carbonic bite that can help offset perceived heaviness or sweetness.  You can fix that post-boil.  You could also add a splash of a dry, bitter Pilsner (got any Jever lying around?) and see if that reduces the impression of sweetness.  If so, you know you need to bump up the IBUs next time.
Title: Re: Help my Kolsch finish fermenting
Post by: gsandel on July 09, 2012, 07:54:05 PM
My experience (this week) with Wyeast's Kolsch yeast on an American Wheat was this:

Pitched two smack packs in 12 gallons of 1.048 wort at 65 degrees.  Yeast was dated a week or so before, so fresh.  My ambient fermentation temp is 65 degrees, but this yeast went gangbusters, rose to about 80 degrees for 1 day, dropped to 72 on 2nd day, and back into mid 60's by 3rd (and done).  Finished at 1.011.  I let it go another 4 days at 65 to clean up and now lagering in the upper 30's.

I never had that yeast spike in temp like that, but it finished where I thought it should (based on my experience with this recipe and yeast in my brewery).

I just worry about the high fermentation-caused temp having the yeast throw some off flavors.
Title: Re: Help my Kolsch finish fermenting
Post by: beersabound on July 10, 2012, 03:36:48 AM
Cool. I am adding a Thermapen and stir plate to my brewing list.

I have never done a forced fermentation test. Good to know about.

I've got it sitting at room temp now and will check the gravity in a few days and then lager it.

Thanks again!
Title: Re: Help my Kolsch finish fermenting
Post by: Pinski on July 10, 2012, 04:49:03 AM
Cool. I am adding a Thermapen and stir plate to my brewing list.
You won't regret this decision.
Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 10, 2012, 04:53:58 PM
Cool. I am adding a Thermapen and stir plate to my brewing list.
You won't regret this decision.

+1  And, as a bonus, you can use it for, you know, cooking...
Title: Re: Help my Kolsch finish fermenting
Post by: beersabound on July 15, 2012, 05:17:46 AM
For anyone who cares, after setting it at room temp for a week the gravity is 1.010. So it dropped three points. And that rocks.

So, I racked it into kegs and they are chilling at 40F.  :D
Title: Help my Kolsch finish fermenting
Post by: majorvices on July 15, 2012, 12:17:57 PM
I recommend cold conditioning it at 38 degree or colder for at least 2 weeks. A little fining like Biofine clear or even gelatin will help drop the yeast.
Title: Re: Help my Kolsch finish fermenting
Post by: bluesman on July 15, 2012, 01:07:29 PM
I recommend cold conditioning it at 38 degree or colder for at least 2 weeks. A little fining like Biofine clear or even gelatin will help drop the yeast.

+1

Cold conditioning really makes a difference with this beer.  I like 4 weeks in the lagering chamber. The amount of time is a personal choice as long as the beer can condition at lagering temp for at least a couple weeks.
Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 16, 2012, 02:16:35 PM
I agree with both comments about doing what you can to clarify it, and to lager it sufficiently.  I normally go 4 weeks at 38-40F, and use some kind of finings (what I use varies, just about anything works if it drops yeast).  Kolsch is normally filtered, and clarity is an important part of the style.  That yeast is very powdery, so it almost never will floc on its own, at least not in the time before the beer starts to go off.  Drink it young, but don't rush the cold conditioning.
Title: Re: Help my Kolsch finish fermenting
Post by: nateo on July 16, 2012, 02:21:39 PM
I usually "lager" in the bottle since I only have one fermentation freezer. After it hits terminal gravity I'll drop the temp in the freezer to around 36* for a week or so, then bottle it, let it carb, and then put it in the fridge for a few weeks before I start drinking it.

Would it be better to lager in bulk?
Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 16, 2012, 02:25:42 PM
If you're bottle conditioning, it's basically the same as lagering in bulk.  However, I doubt you'd get it clear enough by just bottle conditioning.  If that's OK with you, then it probably doesn't matter much.
Title: Re: Help my Kolsch finish fermenting
Post by: nateo on July 16, 2012, 02:39:01 PM
If you're bottle conditioning, it's basically the same as lagering in bulk.  However, I doubt you'd get it clear enough by just bottle conditioning.  If that's OK with you, then it probably doesn't matter much.

I use gelatin finings while it's cold crashing in primary, then I'll bottle it with a more flocculant yeast (like a Prise de Mousse). I don't personally care about clarity all that much, but I like knowing the "proper" way to do things, so I know what advice I'm ignoring.
Title: Re: Help my Kolsch finish fermenting
Post by: scott on July 16, 2012, 02:59:13 PM
I'm also making my first Kolsch.  I've been lagering it for about 2 weeks at 35 F.  I plan to lager for another 2 weeks.  When I bottle do I need to add more yeast, or will there be enough suspended to ferment the priming sugar?  I am not planning on adding any fining agents.

I fermented this batch at around 56-58 F then slowly raised the temp to 65 F, where it stayed for 3 days, then I cooled it to 35.
Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 16, 2012, 03:24:06 PM
If you're bottle conditioning, it's basically the same as lagering in bulk.  However, I doubt you'd get it clear enough by just bottle conditioning.  If that's OK with you, then it probably doesn't matter much.

I use gelatin finings while it's cold crashing in primary, then I'll bottle it with a more flocculant yeast (like a Prise de Mousse). I don't personally care about clarity all that much, but I like knowing the "proper" way to do things, so I know what advice I'm ignoring.

If what you bottle tastes ok (not too 'green') then that should work. I worry about about the 'cold crashing' statement, and whether it gives you enough conditioning. The yeast are helping with more than carbonation at this stage; I'm not sure if different strains will do the same thing. But try it. If you find it doesn't condition or mature satisfactorily, then let it lager on the primary strain longer. I suspect your approach will work, and the clarity should be pretty good since you are fining it. But I haven't tried that myself, so that's only conjecture.
Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 16, 2012, 03:26:04 PM
I'm also making my first Kolsch.  I've been lagering it for about 2 weeks at 35 F.  I plan to lager for another 2 weeks.  When I bottle do I need to add more yeast, or will there be enough suspended to ferment the priming sugar?  I am not planning on adding any fining agents.

I fermented this batch at around 56-58 F then slowly raised the temp to 65 F, where it stayed for 3 days, then I cooled it to 35.

If you aren't fining it, you should have plenty of yeast for carbonation using this approach. 
Title: Re: Help my Kolsch finish fermenting
Post by: nateo on July 16, 2012, 04:18:22 PM
If you find it doesn't condition or mature satisfactorily, then let it lager on the primary strain longer. I suspect your approach will work, and the clarity should be pretty good since you are fining it.

That's where the wicket gets sticky. I haven't done enough back-to-back comparisons trying different techniques to know if what I do is a good way to do it. It's not a horrible way, but probably not "best practice."
Title: Re: Help my Kolsch finish fermenting
Post by: bluesman on July 16, 2012, 05:00:41 PM
If you find it doesn't condition or mature satisfactorily, then let it lager on the primary strain longer. I suspect your approach will work, and the clarity should be pretty good since you are fining it.

That's where the wicket gets sticky. I haven't done enough back-to-back comparisons trying different techniques to know if what I do is a good way to do it. It's not a horrible way, but probably not "best practice."

I agree with Gordon...try lagering on the yeast for a few weeks longer.  This will allow the yeast to really settle out and help clear the beer.  I do this for all of my lagers and my Kolsch as well.  My Kolsch currently on tap is crystal clear after 4 weeks lagering on the yeast. Note: I didn't use any finings either.
Title: Re: Help my Kolsch finish fermenting
Post by: morticaixavier on July 16, 2012, 05:50:04 PM
If you find it doesn't condition or mature satisfactorily, then let it lager on the primary strain longer. I suspect your approach will work, and the clarity should be pretty good since you are fining it.

That's where the wicket gets sticky. I haven't done enough back-to-back comparisons trying different techniques to know if what I do is a good way to do it. It's not a horrible way, but probably not "best practice."

I agree with Gordon...try lagering on the yeast for a few weeks longer.  This will allow the yeast to really settle out and help clear the beer.  I do this for all of my lagers and my Kolsch as well.  My Kolsch currently on tap is crystal clear after 4 weeks lagering on the yeast. Note: I didn't use any finings either.

This is good to know. I have a kolsch brew coming up and I have a 60 day window to have it ready for a comp. I am now thinking this gives me 4 weeks on the yeast (is that including or excluding primary fermentation time?) and 2-4 weeks cold condition in the keg. Does this sound good?
Title: Re: Help my Kolsch finish fermenting
Post by: gordonstrong on July 16, 2012, 07:20:32 PM
If you find it doesn't condition or mature satisfactorily, then let it lager on the primary strain longer. I suspect your approach will work, and the clarity should be pretty good since you are fining it.

That's where the wicket gets sticky. I haven't done enough back-to-back comparisons trying different techniques to know if what I do is a good way to do it. It's not a horrible way, but probably not "best practice."

I agree with Gordon...try lagering on the yeast for a few weeks longer.  This will allow the yeast to really settle out and help clear the beer.  I do this for all of my lagers and my Kolsch as well.  My Kolsch currently on tap is crystal clear after 4 weeks lagering on the yeast. Note: I didn't use any finings either.

With what yeast?  I use either the Wyeast or White Labs Kolsch yeast, and they never seem to totally drop bright, let alone crystal clear.  For competition, I'd always either fine or filter it.  For just drinking at home, I'd RDWHAHB.
Title: Re: Help my Kolsch finish fermenting
Post by: majorvices on July 16, 2012, 10:43:47 PM
10 ml of Biofine clear A3 and my last kolsh dropped close to crystal clear in 24 hours.

(http://i111.photobucket.com/albums/n137/majorvices/photo.jpg)

That's after "lagering" on yeast cake in better bottle for about 10 days after fermentation was finished, then straight to keg, added biofine, shook for carbonation and tapped the next day.
Title: Re: Help my Kolsch finish fermenting
Post by: bluesman on July 17, 2012, 01:27:15 AM
If you find it doesn't condition or mature satisfactorily, then let it lager on the primary strain longer. I suspect your approach will work, and the clarity should be pretty good since you are fining it.

That's where the wicket gets sticky. I haven't done enough back-to-back comparisons trying different techniques to know if what I do is a good way to do it. It's not a horrible way, but probably not "best practice."

I agree with Gordon...try lagering on the yeast for a few weeks longer.  This will allow the yeast to really settle out and help clear the beer.  I do this for all of my lagers and my Kolsch as well.  My Kolsch currently on tap is crystal clear after 4 weeks lagering on the yeast. Note: I didn't use any finings either.

With what yeast?  I use either the Wyeast or White Labs Kolsch yeast, and they never seem to totally drop bright, let alone crystal clear.  For competition, I'd always either fine or filter it.  For just drinking at home, I'd RDWHAHB.

WLP029...and just about crystal clear.  This batch is the clearest I've ever seen a Kolsch without fining.  I was pleasantly surprised.
Title: Re: Help my Kolsch finish fermenting
Post by: tschmidlin on July 17, 2012, 06:24:09 AM
That's after "lagering" on yeast cake in better bottle for about 10 days after fermentation was finished, then straight to keg, added biofine, shook for carbonation and tapped the next day.
No racking between biofine and shaking for carb?
Title: Help my Kolsch finish fermenting
Post by: majorvices on July 17, 2012, 02:33:15 PM
That's after "lagering" on yeast cake in better bottle for about 10 days after fermentation was finished, then straight to keg, added biofine, shook for carbonation and tapped the next day.
No racking between biofine and shaking for carb?

Nope. But I left almost all the yeast behind in the primary (careful racking). It was only slightly hazy when I was racking. And, of course, I poured out the first pint and a half of yeasty beer from the keg.