Anyone trying part-open fermentation?

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richardtmorgan

richardtmorgan

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I've started using a new technique to ferment my higher gravity beers. I ferment open (i.e. with the bucket lid on, but not sealed) for the first 36 hours, and then seal the lid for the remainder of the fermentation process. Anyone else doing this? Any thoughts?

I used to open ferment all my British Bitter for the whole fermentation period. I never had an issue with contamination. For my regular beer I now aerate, seal the bucket and use a three piece airlock (why take a chance?).

However - a bit of a mess with a high gravity beer fermented with s-04 meant that I needed a different solution.

My choice has been open fermentation while the fermentation is getting started and while it is very vigorous followed by sealing the lid once the fermentation has slowed a little. In reality this means if I brew on a Saturday I seal the fermenter first thing on Monday morning.

My theory is this: In the first hours after pitching the yeast need as much oxygen as possible - the open fermentation assists this. As fermentation takes off, the yeast are producing lots of co2 in these higher gravity beers. Because the co2 is heavier than the air it produces a natural blanket on top of the wort. At 36 hours the fermentation is still strong enough to be producing a good co2 blanket, but not so strong to risk blow off - so it's safe to seal the fermenter.

The advantage is that it's very straight forward and there no mess to have to clear out of a blow off tube.

I use this technique any time I ferment a high gravity beer with a fast fermenting yeast.

Has anyone else done this and have you had any issues?
 
I do this for just about all of my ales, particularly when using British top-cropper strains. It works great. I also use a slightly wider and larger bucket than your average brew bucket, so i can ferment 6 gallons with about 1.5-2 gallons headspace. Never needed a blow-off ever and no issues with oxidation. I think oxidation only becomes an issue with secondary, which I never do.
 
This makes a lot of sense to me. I may try it since I don't like using a blow off tube very much...
 
I do this with all my beer - never had an infection. In the carboy I just put loose sanitized tin foil over the mouth. I pitch rehydrated dry yeast (or liquid with proper starter) at 65Fish into pretty big beers and never have blowoff mess, just nice krausen. I wonder if the back-pressure from airlocks is what causes the mess some of the time as I never see it...
 
I've done a couple pseudo open ferments from start to finish. That is to say it was a barrel with non-airtight lid from pitching straight through to keg day. They didn't have any problems. Being inside a ferm chamber probably helped keep anything nasty out in addition to being covered.

In this situation I would agree that the "CO2 blanket" effect would be enough to prevent oxygen contact. Unfortunately in the case of a big beer you'd may want some extended oxygen contact time if you lack the abilities to aerate with O2. Leaving the lid off for a truly open ferment might allow this. Molecular motion would allow atmospheric air to mix in with the produced CO2 to an extend and may assist with the fermentation.

One this I do like about this is that is can allow for a significantly less dramatic blow off if one were to occur. A bit of bubbling or oozing over the edge is plenty more desirable than a full blown mop-the-ceiling explosion featuring glass shards embedded in the wall. Even better if you have a bit of a prediction is blow off may occur and can move that fermenter to a bathtub or rubbermaid bin.

Any volunteers for the "High gravity non-aerated airlock vs open fermentation experiment"?
 
I've done several open ferments, one high gravity, and all turned out fine, without infections and without oxidation. I clamp on the lid on once the krausen falls.

Yeast definitely need oxygen at the beginning. There is debate as to how the weight of CO2 vs O affects the air near the surface of a fermenting vessel as there is mixing in some measure. Some have posted that there is complete mixing of the different gases.
 
At some point I moved into wort temperature controlled fermentation. In that instead of just measuring the ambient air temperature of my fermentation chamber, I implemented a thermowell to get the temp probe into the fermenting wort.

I also used buckets with the thermowell inserted through the predrilled airlock hole. And, instead of messing with a blowoff I just lay the lid loosely on top to allow foam to over flow if necessary into a bus-bin. I also spritz sanitized the interior of my ferm chamber before each use.
 
It's slightly off topic - but I toured Bass brewery a while ago where the guy from the brewery's take was that as long as the fermentation temperature wasn't too high then there were no off flavors and the consequence was just a longer fermentation. I know that's not the whole picture - some of those flavors are desirable in smaller quantities - but my basement sits very close to a constant 60F and so the wort never gets over 65F and all the ales I brew have tasted good. So I've not been fussed with accurate fermentation temperature control and a slightly lower temperature helps resist blow off in any event.
 
richardtmorgan said:
It's slightly off topic - but I toured Bass brewery a while ago where the guy from the brewery's take was that as long as the fermentation temperature wasn't too high then there were no off flavors and the consequence was just a longer fermentation. I know that's not the whole picture - some of those flavors are desirable in smaller quantities - but my basement sits very close to a constant 60F and so the wort never gets over 65F and all the ales I brew have tasted good. So I've not been fussed with accurate fermentation temperature control and a slightly lower temperature helps resist blow off in any event.
Click to expand...

Once I implemented wort based temp control I also began playing with both ends of the spectrum. Lagers at the near lower limits of fermentation and belgian ales using wine strains at 80+ degrees thus developing a strong respect for a brewers ability to manipulate beers via fermentation controls thus exploiting the limits of yeast byproducts.
 
Yes - I had a Saison that I fermented upstairs wrapped in a blanket - so I can see the desirability of temperature control. It sounds a fun thing to play with.
 
I've mostly been doing fairly low gravity English styles as of late because I have a sack of Maris Otter. Every brew I just leave the lid on loose and put a sanitized dial thermometer thermometer in the airlock hole of the lid and haven't had a problem yet. Usually after 3 days I clamp the lid down and replace the thermometer with an airlock as I'm pretty comfortable the temp won't get higher than it has in those 3 days.

It works for me because I don't have much money for a lot of equipment, and I've found that most ales are just fine on a chair in my basement in the late fall/winter/early spring.
 
lowtones84 said:
It works for me because I don't have much money for a lot of equipment, and I've found that most ales are just fine on a chair in my basement in the late fall/winter/early spring.
Click to expand...

I agree - and for me at least, simpler is better. I look back to the traditional methods brewers used, reasoning this is a closer comparison to what I can do now on the homebrew scale. Open fermenting is one method I've taken to heart. I've probably cycled my current yeast strain 10 generations, not counting the multiple jars collected and reused each generation. No infections using this method, and interestingly the only infection I've experienced at all was on a closed ferment using a new yeast pack. :mug:
 
The same method worked out for me too....
I have brewed a simple ale, in order to check it out. it wae in the late spring (the temp was in the low 80f). i ptiched a nice, big and healthy starter... after 5 hours there was some krausen.

Here are some pics of the fermentation in imgur:
http://imgur.com/a/CVX9d
 
I've been fermenting in a little Speidel 3 gal fermenter for over two years without any air lock, just a loose lid. Never any infections and beer always tastes great.
 
I use a brute trash can to ferment in just put the lid on no seal or any thing. I brew about every 10 days and transfer to kegs durring the mash. Works great and was cheaper than buying 3 buckets for 15gal batches
 
I have modified my fermenting along these same lines. I found myself getting tired of baby sitting the occasional batch that would push krausen into the air lock. So one day I decided to just remove the air lock completely then soak a paper towel in starsan. I just lay the damp sanitized paper towel over the air lock and let the krausen ooze out over the top of the lid. I find it so much easier to clean up a little mess during that active fermentation period than worry about the lid blowing off. To my surprise I haven't noticed any ill effects with this technique yet either ( ;
 
So the extension of that is not to seal the lid at all to begin with and then there won't even be the krausen dribbling out of the open airlock hole to take care of...
 
maybe a new thread should be started, but this whole co2 blanket thing just cracks me up. it's goes completely against common sense. let's say that some kind of blanket could form, if you had even the slightest bit of air circulation in your house, that blanket would easily break up. so unless you're fermenting in a vacuum, then it's unlikely you have a co2 blanket. while the vessel is completely sealed, you can theoretically get the co2 being released to push out the oxygen. but the moment you open the lid and wave your hand around the top of the vessel while you get hoses and such in place, the co2 will mix with the open air fairly quickly.

i believe the thing that's protecting the beer the most during that time is the krausen. so if it were me, i would simply seal up the lid when i noticed the krausen dropping. i believe that's the common practice with people doing open fermentations, although there are some people reporting open fermentation throughout the duration and not having any problems. it is the original method of fermentation after all. i suppose with that method if you made sure the fermentation environment was completely sterile, you shouldn't really have any problems.

from what i've read the benefit of open fermentation isn't just the extra oxygen for the yeast, but also the fact that the yeast aren't having to work under pressurized conditions. anybody whose ever fermented in plastic buckets can easily know how much pressure is in there. especially when i had a high gravity beer, i thought the lid was going to be ready to pop off because of the pressure.
 
So far I guess I have been lucky in that I have been using sealed buckets with air locks, however I did have one very active fermentation a little over a week ago on a stout that caused it to blow one side of the lid off resulting in a fair amount of mess to clean off the side of a dresser and wall, luckily nothing made it to the carpet before I caught it and switched it over to a blow off tube setup.

I have done stouts previously so I am not sure why this one happened to be different but if I end up doing the same recipe again maybe I will try not sealing the bucket this time and letting it have its way with it until the krausen subsides. The idea of an open fermentation is intriguing to say the least, I guess I have just been overly cautious worrying about a possible infection in my liquid gold. :)
 
joshesmusica said:
maybe a new thread should be started, but this whole co2 blanket thing just cracks me up. it's goes completely against common sense. let's say that some kind of blanket could form, if you had even the slightest bit of air circulation in your house, that blanket would easily break up. so unless you're fermenting in a vacuum, then it's unlikely you have a co2 blanket. while the vessel is completely sealed, you can theoretically get the co2 being released to push out the oxygen. but the moment you open the lid and wave your hand around the top of the vessel while you get hoses and such in place, the co2 will mix with the open air fairly quickly.

i believe the thing that's protecting the beer the most during that time is the krausen. so if it were me, i would simply seal up the lid when i noticed the krausen dropping. i believe that's the common practice with people doing open fermentations, although there are some people reporting open fermentation throughout the duration and not having any problems. it is the original method of fermentation after all. i suppose with that method if you made sure the fermentation environment was completely sterile, you shouldn't really have any problems.

from what i've read the benefit of open fermentation isn't just the extra oxygen for the yeast, but also the fact that the yeast aren't having to work under pressurized conditions. anybody whose ever fermented in plastic buckets can easily know how much pressure is in there. especially when i had a high gravity beer, i thought the lid was going to be ready to pop off because of the pressure.
Click to expand...

When I did open fermentation I did it in my shower room.. So it's a lot of things, but it not sterile :)
The co2 blanket along with the krausen form a protecting blanket. And every day you should take off the Krausen. My ale started 1.050 and after Two days the FG 1.008..These conditions are PERFECT for an ale strain..
 
benda86 said:
When I did open fermentation I did it in my shower room.. So it's a lot of things, but it not sterile :)
The co2 blanket along with the krausen form a protecting blanket. And every day you should take off the Krausen. My ale started 1.050 and after Two days the FG 1.008..These conditions are PERFECT for an ale strain..
Click to expand...

To what end are you removing the krausen at all?
 
I skim off the krausen, but just so I can harvest yeast. First skim at 24 hours to remove hops and other gunk, then again at 48 hours to harvest the clean yeast. Any krausen that forms after that just gets left in the fermentor - no need to remove.
 
GilaMinumBeer said:
To what end are you removing the krausen at all?
Click to expand...

The purpose of removing the krausen is to remove any airborne bacteria the might have landed on the krausen. Plus... After skimming of the krausen, you should take a long spoon and arouse the yeast by mixing the beer.
 
benda86 said:
The purpose of removing the krausen is to remove any airborne bacteria the might have landed on the krausen. Plus... After skimming of the krausen, you should take a long spoon and arouse the yeast by mixing the beer.
Click to expand...

so first you claim the krausen and co2 blanket will keep off unwanteds, then you claim they're landing in the krausen?

do you have any material that can back up the claims of the need to do this?

again, yes the beer is releasing a lot of co2, but if you have any, and i mean any, airflow whatsoever in your fermenting room, then that blanket is being removed at a fairly quick pace as well.

i have no problem with open fermentation, to be clear, just with the myth of the co2 blanket in an open vessel. in my opinion (and it is just an opinion based on common sense), the krausen is basically the only thing protecting the beer from contaminates in the beginning. but i'm also willing to be proven wrong with some strong data to support an opinion.
 
joshesmusica said:
i have no problem with open fermentation, to be clear, just with the myth of the co2 blanket in an open vessel. in my opinion (and it is just an opinion based on common sense), the krausen is basically the only thing protecting the beer from contaminates in the beginning. but i'm also willing to be proven wrong with some strong data to support an opinion.
Click to expand...

For the first part. The answer is yes. The krausen do get bacterias and the co2 also helps.. You may find some biology articles online that will states that (some) bacteria prefer an enriched O2 environment.

In my opinion (which is based on what I read) this blanket is a mix of the two above. The name of the game is "competition". Between your yeast cells and the unwanted. Thus it is not only the krausen, it's a whole bunch of factors that adds up to the thing we call open fermentation.
 
benda86 said:
For the first part. The answer is yes. The krausen do get bacterias and the co2 also helps.. You may find some biology articles online that will states that (some) bacteria prefer an enriched O2 environment.

In my opinion (which is based on what I read) this blanket is a mix of the two above. The name of the game is "competition". Between your yeast cells and the unwanted. Thus it is not only the krausen, it's a whole bunch of factors that adds up to the thing we call open fermentation.
Click to expand...

that's fine if it's a mix of the krausen and the co2 being emitted. but don't call it a co2 blanket. it's not. co2 dissipates into the air fairly quickly. quicker if the air around it is moving. the way people talk about the co2 blanket is as if it's this thick, impenetrable layer of air sitting below everything else. in an open vessel, that's simply not the case.

but can you find and post these articles that talk about the krausen harboring bacteria, and therefore a need to constantly skim it off?
 
"In an open fermentation, especially one in which the level of liquid is well below the upper lip of the container, the pressure of carbon dioxide gas leaving the solution will lower the amount of oxygen reaching the surface, compared to if the liquid was not fermenting."
Key words:
Well below.
Will lower the amount.
Compared to if it wasn't fermenting.
So maybe if you're generous then you could call 5 gallons well bellow the lid of a six gallon bucket?
And then if it's well below, then the amount of oxygen will be reduced, not blanketed away.
Then you can only compare that number to the amount of oxygen reaching it if it wasn't fermenting.
That's a lot of conditions to consider in order to get a semi-blanket.
So again, no such thing as a co2 blanket keeping stuff out. The co2 the escapes joins the adjacent air, it's just that co2 continually escapes, and that helps.
 
Well.. have you ever brewed using the open fermentation method? If not (which is probably so) you should try this first. And after that be my guest, and try to convince me why my beer is not inhabited with mold and fungee. Indeed the krausen forms a barrier to the unwanteds.. But after the 24 hours to the procces, I skimmed off the krausen and the beer was exposed to bactirias and such.
So... I there is no krausen to help, and the co2 don't help also.. Than how can you explain the fact that the beer did NOT got infected?
 
i think you're misunderstanding my point. i even said at one point that i have no problem with open fermentation and do plan to try it. i do believe the krausen and the output of co2 help to keep the unwanteds out, and i never claimed otherwise. i simply took up issue with the co2 blanket.
 

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