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General Category => Yeast and Fermentation => Topic started by: scooter2374 on June 30, 2011, 12:15:04 AM

Title: Such a thing as over-pitching?
Post by: scooter2374 on June 30, 2011, 12:15:04 AM
Is it possible to pitch too much yeast? I know that not pitching enough can stress the yeast but what about vise versa?
Title: Re: Such a thing as over-pitching?
Post by: tom on June 30, 2011, 01:22:31 AM
Yes, but it takes a lot for the usual yeasts.
Yeast that produce a lot of the beer flavor such as hefeweizen, Belgians, etc. are more sensitive to the pitching rate.
Title: Re: Such a thing as over-pitching?
Post by: majorvices on June 30, 2011, 02:54:51 AM
The real problem with over pitching comes usually from pitching slurry that has large amounts of dead cells and/or trub, which can cause problems in the finished beer (as in pitching directly on a yeast cake). Of course, over pithcing can also change the character of the beer as well, especially on the styles mentioned by Tom.
Title: Re: Such a thing as over-pitching?
Post by: tygo on June 30, 2011, 03:01:26 AM
You certainly could overpitch and that might cause less than optimal flavors.  But on a homebrew scale I don't think it's something to worry about.  I think we struggle, even with starters, to pitch enough yeast usually.  At least, I think I do.  Hard to really know without going the science geek route and counting cells.

If you pitch directly on an entire yeast cake that's a different story of course.  I never do that unless I'm making a truly monstrous beer.
Title: Re: Such a thing as over-pitching?
Post by: jklinck on June 30, 2011, 05:25:09 AM
You certainly could overpitch and that might cause less than optimal flavors.  But on a homebrew scale I don't think it's something to worry about.  I think we struggle, even with starters, to pitch enough yeast usually.  At least, I think I do.  Hard to really know without going the science geek route and counting cells.

If you pitch directly on an entire yeast cake that's a different story of course.  I never do that unless I'm making a truly monstrous beer.

Burial Chair Wee Heavy sounds like one of those monstrous beers. Great name.
Title: Re: Such a thing as over-pitching?
Post by: tygo on June 30, 2011, 11:05:31 AM
Burial Chair Wee Heavy sounds like one of those monstrous beers. Great name.

Thanks.   ;)

OG 1.126. Just over 12% ABV.  That one definitely got pitched on a yeast cake.
Title: Re: Such a thing as over-pitching?
Post by: mswilliams1975 on July 01, 2011, 09:15:49 PM
not tohijack the thread but whats a yeast cake?
Title: Re: Such a thing as over-pitching?
Post by: denny on July 01, 2011, 09:20:47 PM
not tohijack the thread but whats a yeast cake?

The yeast in the bottom of a fermenter after you rack the beer off. 
Title: Re: Such a thing as over-pitching?
Post by: rbclay on July 01, 2011, 10:52:32 PM
contrary to popular opinion- and perhaps scientific "fact"- I believe in pitching directly onto yeast cakes. In my experience this "overpitching" produces great beers. I step up the OG of each successive batch. Meaning the first batch would be, for example, a mild at OG 1035-1040, followed by a brown porter OG 1040-1050, then maybe a robust porter or barleywine. My thinking has been that I would rather not bother with harvesting the yeast, but brew on the day I am ready to rack or bottle the previous batch. I do also save yeast if I don't have the time to brew, but pitching directly on yeast cakes is a procedure I will continue to do and hope to continue making award-winning beers as a result. Not to brag, but more as a point of justification, I recently won my first ever medal (silver) at Nationals with a brown porter pitched onto a fresh yeast cake!
Title: Re: Such a thing as over-pitching?
Post by: nateo on July 02, 2011, 11:53:43 AM
From my experience, pitching on a yeast cake = more yeast = faster ferment = more heat. If you have good fermentation temp control, I think it's less of a problem to pitch on a yeast cake. I've gotten some fusel/hot alcohol flavor from the times I've pitched onto a whole yeast cake, but I think that's more to do with my cooling and less to do with the pitching rate, per se.
Title: Re: Such a thing as over-pitching?
Post by: majorvices on July 02, 2011, 12:52:19 PM
contrary to popular opinion- and perhaps scientific "fact"- I believe in pitching directly onto yeast cakes. In my experience this "overpitching" produces great beers. I step up the OG of each successive batch. Meaning the first batch would be, for example, a mild at OG 1035-1040, followed by a brown porter OG 1040-1050, then maybe a robust porter or barleywine. My thinking has been that I would rather not bother with harvesting the yeast, but brew on the day I am ready to rack or bottle the previous batch. I do also save yeast if I don't have the time to brew, but pitching directly on yeast cakes is a procedure I will continue to do and hope to continue making award-winning beers as a result. Not to brag, but more as a point of justification, I recently won my first ever medal (silver) at Nationals with a brown porter pitched onto a fresh yeast cake!

As long as you are going from a lower gravity beer to a higher gravity beer you can usually get away with it, and as long as you are not carrying dead cells over for more than 2 or 3 generations at most. And, perhaps, had you pitched a more "proper" slurry of yeast you may have gotten gold.  ;)

From my experiences over pitching can definitely lead to problems in the finished beer. You can certainly get away with it from batch to batch but I really believe you will have more consistent results if you aim for a "proper" pitch every time.
Title: Re: Such a thing as over-pitching?
Post by: majorvices on July 02, 2011, 12:55:27 PM
BTW here is an excellent article on pitching rates, both over and under: http://www.byo.com/component/resource/article/1749-yeast-pitching-rates-advance-homebrewing
Title: Re: Such a thing as over-pitching?
Post by: hopfenundmalz on July 02, 2011, 02:25:08 PM
BTW here is an excellent article on pitching rates, both over and under: http://www.byo.com/component/resource/article/1749-yeast-pitching-rates-advance-homebrewing

I probably read that when published, but may have gotten more out of it today.
Thanks for the link.
Title: Re: Such a thing as over-pitching?
Post by: tom on July 02, 2011, 03:50:33 PM
The real problem with over pitching comes usually from pitching slurry that has large amounts of dead cells and/or trub, which can cause problems in the finished beer (as in pitching directly on a yeast cake). Of course, over pithcing can also change the character of the beer as well, especially on the styles mentioned by Tom.
How long would you think the off-flavors take to be absorbed into the beer?
I pitched my 1.090 doppelbock on a yeast cake of a 1.056 Dortmund Export, let it settle for 5-6 hours, and then transferred it off the trub into another fermenter.  I would assume that the dead yeast would settle out.  Any thoughts on that tactic?
Title: Re: Such a thing as over-pitching?
Post by: majorvices on July 02, 2011, 10:49:39 PM
Tom, I don't really know how long it would take for the autolysis to "seep" into the beer. My guess a few days. that said, I hope you have better luck with that technique than myself when I tried it. the effect was like removing half of the yeast. The fermentation slowed to a crawl and never did finish and I ended up dumping the batch. That said, it was a lager, so maybe the fault was that most of teh yeast were still on the bottom.
Title: Re: Such a thing as over-pitching?
Post by: tom on July 02, 2011, 11:42:08 PM
Thanks Keith,  It is fermenting like crazy at a temperature-controlled 48F.  We'll see.
Title: Re: Such a thing as over-pitching?
Post by: seajellie on July 04, 2011, 03:25:11 PM
Tom, that's an interesting technique and not one I have tried before. Sounds like a possibly great combination of simplicity and effectiveness. Please keep us posted how it turns out! If it's a lager, your results should be final just in time for my own personal brewing "season".. thanks!
Title: Re: Such a thing as over-pitching?
Post by: jeffy on July 04, 2011, 03:35:35 PM
That's a method I'd never thought of, Tom.  How long did you wait before siphoning off the trub?  Did you let it get a good kreusen going?
I'm also interested in the results, so please keep us posted.
Title: Re: Such a thing as over-pitching?
Post by: tom on July 04, 2011, 05:18:00 PM
Yep, a 1.090 doppelbock.  So I'll let you know in about 6 months.  5 gallons with 2206 and 5 with 2308.

Chilled to 42F and then let it settle until just before bedtime - that day it was about 5-6 hours.  I wanted to transfer before kraeusen because that would get everything moving again.  I just "siphoned" it into another fermenter with some CO2 help.  I lowered the diptube until I got a little trub and then lifted it a bit.  The first fermenter was a Sanke keg.  Kind of opposite to a conical.  She's still bubbling along at day 8.

Disinhibitor!
Title: Re: Such a thing as over-pitching?
Post by: majorvices on July 04, 2011, 05:36:21 PM
Just to add the flipsyde, when I tried this very technique about 5 years ago the effect was like removing half the yeast. The fermenttaion started off fine but slowed to a crawl and never really finished. It was on an Imperial Pilsner. I was too scared to try again.
Title: Re: Such a thing as over-pitching?
Post by: thomasbarnes on July 05, 2011, 05:34:53 AM
Is it possible to pitch too much yeast? I know that not pitching enough can stress the yeast but what about vise versa?

It's possible, but hard. Excessive pitching rates can increase acetylaldehyde levels and also possibly increase autolysis rates.
Title: Re: Such a thing as over-pitching?
Post by: tom on July 05, 2011, 05:12:34 PM
Just to add the flipsyde, when I tried this very technique about 5 years ago the effect was like removing half the yeast. The fermenttaion started off fine but slowed to a crawl and never really finished. It was on an Imperial Pilsner. I was too scared to try again.
This has been my MO for big beers for years now.  Got a 2nd in the NHC finals for an Old Ale as well as a BOS (in Australia of all places).  Imperial Pilsners, Wee Heavies, and Barleywines have done well too.
YMMV
Title: Re: Such a thing as over-pitching?
Post by: brewmonk on July 10, 2011, 08:45:52 AM
Friday I did a quick kit beer (Muntons Premium Imperial Stout), and because I need a quick turn around, I pitched the dry packet of yeast that came with the kit, along with another dry packet of yeast I had from another kit.  I rehydrated them and I pitched it a bit ... OK ... pretty dang warm, ie  86F  :o ) and the thing was bubbling like mad within two hours, but felt pretty warm.

I got the fermenter into a swamp cooler, although I think it took a while to cool down, got it (the water at least) down to about 68 F by the next morning.  The krausen was pretty intense (a 30 liter bucket with 19.25 liters of wort, the rest was krausen).

Sunday morning it is still bubbling a bit, but has slowed considerably.  We'll see how it ends up.  I'm hoping since it is a stout and a low gravity (OG 1.044) that there won't be any flavor consequences from the comedy that was this batch. Maybe the esters that wouldn't be produced from yeast reproduction my be compensated for by the hot fermentation  :-\ . I'm hoping I can bottle by Friday.

If nothing else this may just be one of those "learning experiences"  ::)