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General Category => Yeast and Fermentation => Topic started by: brewmasternpb on April 05, 2011, 03:23:42 AM

Title: Open fermenting a Saison
Post by: brewmasternpb on April 05, 2011, 03:23:42 AM
I was thinking about using open fermentation with a Saison in June.  The main reason for using open fermentation is that it increases esters and phenols correct?  Can anyone think of any reason that open fermenting a Saison would be undesireable?
Title: Re: Open fermenting a Saison
Post by: ryang on April 05, 2011, 02:47:41 PM
As long as you are working in a clean area, there's no reason not to go for it.

Title: Re: Open fermenting a Saison
Post by: jeffy on April 05, 2011, 02:54:16 PM
I was thinking about using open fermentation with a Saison in June.  The main reason for using open fermentation is that it increases esters and phenols correct?  Can anyone think of any reason that open fermenting a Saison would be undesireable?
Why would you think that an open fermentation would promote esters and phenols?  I'm thinking it would only do two things, first there would be no head pressure from the activity which wouldn't make much difference on a homebrew scale and second it would make the wort more susceptible to contamination.
Or am I missing something?
Title: Re: Open fermenting a Saison
Post by: ryang on April 05, 2011, 03:00:12 PM
He may be referencing a BrewingTV where they did a side by side of an ale (a wheat?  can't remember for sure) that was open fermented and one with a lid.  In their tasting notes, they seemed to believe that the open fermented one was more estery/phenolic.

I was slightly skeptical, but haven't tried side by side.
Title: Re: Open fermenting a Saison
Post by: jackson1 on April 05, 2011, 03:02:39 PM
I recently brewed a Saison using Wyeast 3724 and my understanding was if you boost the fermenting temp that would boost the Esters and phenols.  I built a cardboard box, put a small electric heater in front of it and raised and held the temp at right around 85°F - 90°F.  I know this seems stupid high but the beer turned out excellent.  This was all done in a 6.5 Gal Carboy with a blowoff tube.
Title: Re: Open fermenting a Saison
Post by: tumarkin on April 05, 2011, 03:06:36 PM
This is not 'stupid high' for saison yeast. They need the high temps to perform well.
Title: Re: Open fermenting a Saison
Post by: Joe Sr. on April 05, 2011, 03:08:26 PM
What sort of attenuation did you get at that temp?

I have a very hard time getting this yeast to fully attenuate even when I raise the temp into the 70s.  I'm actually thinking about not using this yeast again, just cuz it was such a pain.
Title: Re: Open fermenting a Saison
Post by: jackson1 on April 05, 2011, 04:06:17 PM
Mine finished around 1.008 from what I remember (I don't have access to my notes at the moment).  The higher temp seemed to work out just fine.  I was very hesitant to run it at that temp (I usually ferment at around 65°F)  but I was very happy with the results.  We'll see what the judges think (I sent a bottle to the NHC).  I read that that yeast like to stop before it is complete but that certainly wasn't my experience.
Title: Re: Open fermenting a Saison
Post by: euge on April 05, 2011, 05:26:08 PM
I was thinking about using open fermentation with a Saison in June.  The main reason for using open fermentation is that it increases esters and phenols correct?  Can anyone think of any reason that open fermenting a Saison would be undesireable?

I do it because it's easier. But, it's just laying the lid on the bucket during the attenuative phase. Once that is past I'll snap the lid down if not transferring immediately to some other vessel. With a carboy one could just cover the mouth and neck with a piece of foil.

As a caveat, you don't want to leave your fermenter "uncovered" generally. I ferment in chambers so the buckets are still protected from ambient air movement. Leaving one out with the lid off will almost certainly result in contamination.

I read years ago about pressure affecting the esters and whatnot. Doesn't seem to matter at the homebrew level, though had a saison's krausen drop immediately one time when I pressed hard on the lid of the fermenter. Despite that the beer was fine.
Title: Re: Open fermenting a Saison
Post by: denny on April 05, 2011, 06:14:17 PM
The main reason for using open fermentation is that it increases esters and phenols correct?

Boy, not that I noticed the few times I tried it.  I'm hard pressed to think of a reason why it would.
Title: Re: Open fermenting a Saison
Post by: tschmidlin on April 05, 2011, 07:11:16 PM
The main reason for using open fermentation is that it increases esters and phenols correct?

Boy, not that I noticed the few times I tried it.  I'm hard pressed to think of a reason why it would.
It could because of the reduced pressure and the extra O2 would allow more yeast growth, giving more byproducts.  It seems unlikely to be a noticeable effect though.
Title: Re: Open fermenting a Saison
Post by: gordonstrong on April 05, 2011, 09:08:12 PM
You can also manipulate the ester profile using fermenter geometry.  Fermenting in something shallow will give more esters.  Works for the Belgians...
Title: Re: Open fermenting a Saison
Post by: denny on April 05, 2011, 09:11:18 PM
It could because of the reduced pressure and the extra O2 would allow more yeast growth, giving more byproducts.  It seems unlikely to be a noticeable effect though.

Or, if you believe Clayton Cone, more yeast growth will give you less esters.
Title: Re: Open fermenting a Saison
Post by: denny on April 05, 2011, 09:11:45 PM
You can also manipulate the ester profile using fermenter geometry.  Fermenting in something shallow will give more esters.  Works for the Belgians...

Gordon, any idea why it works like that? 
Title: Re: Open fermenting a Saison
Post by: johnf on April 05, 2011, 09:14:18 PM
You can also manipulate the ester profile using fermenter geometry.  Fermenting in something shallow will give more esters.  Works for the Belgians...

Gordon, any idea why it works like that? 

Lower hydrostatic pressure is the typical explanation.

I listed to the Anchor interview on TBN from a few weeks back recently. It is sort of amazing that they ferment Steam in fermentors 12-18" deep. That is less deep than a carboy.
Title: Re: Open fermenting a Saison
Post by: gordonstrong on April 05, 2011, 09:18:16 PM
I've been trying for at least the last 10 years to get data on that.  It was one of the things I asked Stan to ask brewers about while he was researching BLAM.  I remember asking about it at a Spirit of Belgium in DC a long time ago.  I've brought it up with several professional brewers.  I don't think there is much research on it, so all I have is experimental results.  I'm guessing it's something akin to the open fermenter concept, in that there is less pressure on the yeast.  That doesn't explain what's happening on a biological level, obviously.  I should check and see if there's anything on it in the new yeast book.
Title: Re: Open fermenting a Saison
Post by: denny on April 05, 2011, 09:24:18 PM
But it's something that you've personally experimented with and confirmed the results?
Title: Re: Open fermenting a Saison
Post by: gordonstrong on April 05, 2011, 09:31:48 PM
Personally run the experiments?  No.  Personally tasted the results of someone else's experiments?  Yes.
Title: Re: Open fermenting a Saison
Post by: denny on April 05, 2011, 09:33:55 PM
Good enough.  Thanks.  If I had an easy way to test the theory, I would.  Guess it's time to put my thinking cap on.
Title: Re: Open fermenting a Saison
Post by: gordonstrong on April 05, 2011, 09:41:16 PM
The person running the experiments worked in the food industry, so he had access to some large shallow food-grade bins.  If you don't want to use those as open fermenters, put some saran wrap over them.
Title: Re: Open fermenting a Saison
Post by: morticaixavier on April 05, 2011, 10:46:52 PM
one of those large plastic tupperware type food service bins might work. the ones that are 24" by 18" by 5" or 6" deep. they usually have a snap on lid that could be drilled for a airlock even.
Title: Re: Open fermenting a Saison
Post by: Mark G on April 05, 2011, 11:04:35 PM
I've done some experimentation with open fermenting hefe's, and really didn't notice much of a difference in esters or phenols. I think that on a homebrew scale, the difference in head pressure has minimal impact. With a saison, you should get plenty of yeast character regardless. Let us know your results though. The only way to find out is to try.
Title: Re: Open fermenting a Saison
Post by: Will's Swill on April 06, 2011, 12:44:24 AM

It could because of the reduced pressure and the extra O2 would allow more yeast growth, giving more byproducts.  It seems unlikely to be a noticeable effect though.

What extra O2?  I thought a CO2 blanket protected the beer form O2?  ???  ;D
Title: Re: Open fermenting a Saison
Post by: denny on April 06, 2011, 03:59:11 PM
I've done some experimentation with open fermenting hefe's, and really didn't notice much of a difference in esters or phenols. I think that on a homebrew scale, the difference in head pressure has minimal impact.

That was also my experience the couple times I tried it.
Title: Re: Open fermenting a Saison
Post by: chumley on April 06, 2011, 04:48:09 PM
I have open fermented bitters with WLP023 Burton and WY1968 Fullers yeast, and I do believe you get more fruity esters compared to fermenting closed (glass carboy for me) primaries.  The WLP023 yeast in particular gives nice apple/pear esters that is pretty much absent in the closed version.

I think that Tom is right....the increased yeast growth resulting from more oxygen available is the reason.

Our club is currently having a SMA2H brew going....10 of us are brewing the same ESB recipe with WY1968, with the only variable is that we are using different base malt.  But I maybe the only one doing an open ferment (I always do with WY1968)....it will be interesting to see if that makes a taste difference when we compare the ESBs at our May meeting.

I haven't tried open fermenting in a weizen, though...I am intrigued.
Title: Re: Open fermenting a Saison
Post by: tschmidlin on April 06, 2011, 05:18:14 PM
I think that Tom is right....the increased yeast growth resulting from more oxygen available is the reason.
I just want to point out that I was speaking hypothetically, and that I said:

It seems unlikely to be a noticeable effect though.

Another possible explanation is the oxidation of various compounds can lead to flavor complexity.  I'm just throwing stuff out, not saying any of these are certainly the cause.
Title: Re: Open fermenting a Saison
Post by: samgamgee on April 14, 2011, 12:20:23 AM
I think the oxygen added is negligible because the krausen and CO2 are going to blanket the fermenting beer and protect it. It's all about fermentor geometry and hydrostatic pressure. Increased CO2 concentrations inhibit ester production, and the deeper the fermentor is, the more CO2 stays in solution because of the hydrostatic pressure. This has been well documented in commercial trials and is published in Brewing With Wheat if I remember correctly, though I've heard it taught in Germany as well when I was over there. You can get a similar ester profile in a CCV with a low enough height-to-width ratio, but most CCVs are just a lot taller than open fermentors. Then the geometry affects convection currents, which also affect CO2 in solution. On a homebrew scale, I see no reason why not covering a carboy or bucket would do anything. The pressure under the airlock is probably negligible to the CO2 levels in solution. A super-shallow pan for a fermentor? I could see that maybe having an affect, but can't say for myself.