Open vs. Closed Fermentation

Discussion in 'Homebrewing' started by bdeast1, May 10, 2012.

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  1. bdeast1

    bdeast1 Initiate (0) Feb 4, 2011 Alabama

    I am getting ready to begin my first home brew and have been trying to read up on different methods. What are the pros and cons of open fermentation? Is it easier for a someone new to home brewing? Also, any recommendations on which style is the easiest to brew?
  2. nathanjohnson

    nathanjohnson Initiate (0) Aug 5, 2007 Vermont

    Open fermentation refers to fermenting in vessels that are not enclosed. This is not relevant to a beginner to homebrewer. Ferment in a bucket or carboy.

    As for easiest style, something like a pale ale, brown ale, porter, or amber ale are solid starting beers.
    quirkzoo likes this.
  3. OddNotion

    OddNotion Zealot (584) Nov 1, 2009 New Jersey

    Open fermentation is a good way to raise your chances of getting your beer infected.
    RWNewhouse likes this.
  4. mnstorm99

    mnstorm99 Initiate (0) May 11, 2007 Minnesota

  5. oregonskibum

    oregonskibum Zealot (511) Mar 14, 2009 Oregon

    Open fermentation in your bathroom bathtub. Amazing results each and every time...

    Seriously though, why consider open fermentation? I'm a new home brewer, but in all my reading on the subject (which has been a lot), the idea of open fermenting really never seemed like an option. Is there something in the air you hope to add to the flavor profile of the beer? Do you have a sealed fermentation chamber preventing typical home based bugs from entering your beer? Unless there's something you're not telling us, ferment in a closed vehicle (like a carboy) and limit the beer's exposure to the air as much as possible.
  6. LeeryLeprechaun

    LeeryLeprechaun Zealot (583) Jan 30, 2011 Colorado

    Open fermentation allows for spontaneous fermentation to occur, ie yeast that are native to the surrounding area are able to colonize the beer and ferment it. The problem is that yeast are not the only micro organisms in the air. Also present are lactobacillus, acetobacter, and a host of other bacteria. If these bacteria get into your beer you are going to end up with something other than a beer you are accustomed to. It will likely be something that is sour, funky, and unpalatable.

    For that reason, and many more, you should stick to closed fermentation where you can control the type of organisms in the beer until you have a really good idea of what you are doing.
    ONovoMexicano likes this.
  7. OddNotion

    OddNotion Zealot (584) Nov 1, 2009 New Jersey

    Also don't forget about literal bugs such as fruit flies that just love the large volume of sugar water in front of them.
  8. marquis

    marquis Champion (803) Nov 20, 2005 England

    I open fermented for 30 years of homebrewing and never lost a batch through infection.I visit breweries where the fermentation takes place in large open tanks which are as old as the hills , you can bet that if this technique caused them any losses they wouldn't continue to use them.Where they do modernise and change to conical fermenters they find it difficult to match the quality.For example Sam Smiths
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  9. arkinsparkin

    arkinsparkin Initiate (0) May 12, 2010 Massachusetts

    Interesting link..
  10. NiceFly

    NiceFly Aspirant (241) Dec 22, 2011 Tajikistan

    I am a bit curious about your process for open fermentation.
    What type of fermenter did you use? Did you just have a bucket without a lid? What was your rationale, was it the state of the art at the time and a function of the equipment available?

    I have to say, on the homebrew scale I do not think that things like fermenter geometry or pressures, hydrostatic or otherwise, make much of a difference. But open fermentation is a bit of a different story. Perhaps not from a pressure perspective but a more subtle oxygen/CO2 exchange perspective. And how is it that your brew never got an infection?
  11. Utawana

    Utawana Initiate (0) Nov 7, 2007 New York

    If by open fermentation you mean putting a lid over the top but not snapping it on, then that is no big deal. The vast majority of my fermentations just have a lid placed loosely over the top to keep dust and whatnot from falling in. If the fruit flies are out I'll wrap the seam with plastic wrap.
    I still ferment smaller batches with buckets and snap on lids - I don't think I notice a difference between my closed and open fermentations.
  12. epk

    epk Initiate (171) Jun 10, 2008 New Jersey

    Nevermind, misread.

    Just follow the directions for now is my advise.
  13. yinzer

    yinzer Aspirant (219) Nov 24, 2006 Pennsylvania


    Can you give us your thoughts on what you need to actually get the benefits of open fermentation. It seems that people are calling a loose lid on a bucket, an open carboy, seemingly anything without a blow-off open-f. I think that there is a certain maximum height/width ratio where you get little pressure on the yeast and also you need a good exposure to the ambient air.
  14. jlpred55

    jlpred55 Initiate (0) Jul 26, 2006 Iowa

    I always open ferment my hefe's. No longer than they are on the yeast and by the time I rack the krausen is still there acting as a protective layer. Now- I don't keep the top wide open but there is no lid snapped on with an airlock.
  15. BrownNut

    BrownNut Devotee (455) Jul 11, 2011 Florida

    Wow, I came here to ask a question about Yorkshire squares and here is this thread already custom tailored for it. Plus somebody already brought my Sam Smith's example. Convenient! If wild ales like Flemish ales used to be made by letting them sit out and ferment naturally with the random yeast present in the area, and they'd get those sour tastes, why doesn't a brewer like Sam Smith's get wild yeast in their stuff while fermenting in those open Yorkshire squares for multiple days? The yeast they use intentionally foams all up and they keep spraying beer from the bottom of the tank on it over and over to get it back into solution. Seems like a lot of exposure. Do the yeast strains they intentionally use somehow crowd out whatever wild yeast may be present? Something else?
  16. epk

    epk Initiate (171) Jun 10, 2008 New Jersey

    You may know this, but I just wanted to make it clear for others benefit. Though open fermentation could lead to spontaneous fermentation given certain conditions, the brewers who utilize such technique are not doing it for that reason. Ommegang and Sierra Nevada both use rectangular, shallow open fermenters but pitch yeast into them just like any typical brewer. Brewers who specifically desire spontaeously fermentation use coolships to cool the wort overnight and allow it to be spontaneously inoculated, but it is then typically transferred to a closed vessel to do the actual fermentation.

    A coolship and an open fermenter, though similar in shape, are not the same thing.
  17. epk

    epk Initiate (171) Jun 10, 2008 New Jersey

    Fermentation probably has a lot to do with it. With a vigorous fermentation, krausen and a Co2 blanket are created quickly. However, I'd also say sanitary conditions without a bunch of windows around to let whatever float on in. Wild Ales specifically use coolships and slatted windows for this. I know Ommegang has their fermentation room of open fermenters in the basement.... and when I toured it they never even showed us... maybe for a reason?

    Maybe Marquis can give us more insight.
  18. BrewMichigan

    BrewMichigan Initiate (0) May 4, 2007 Michigan

    When I was in California talking to the dudes at Sierra Nevada, they told me that at the homebrew scale, there is no noticeable effect of open fermentation. They said on their scale the pressures exerted on the yeast just from the weight of the liquid is enough that when they remove the top (and CO2 pressures) the yeast react differently and may produce more of the fruity phenols we want.
  19. quirkzoo

    quirkzoo Initiate (0) Jul 7, 2011 Colorado

    I think the main difference between the two is windows open or windows closed. Sierra Nevada, Ommegang and the like do an "open" fermentation so that there is not CO2 buildup, pressure and the like, but they do it in a spotless room and they make sure that anyone that goes into that room is equally spotless. The only yeast in those beers is the one they pitch. Notice no windows or people in the picture below.


    Allagash and others that are looking for spontaneous fermentation, leave the windows open:


    They are looking for all manner of small living creature to come and land on their sugar water and eat their fill and poop out alcohol and other flavors.

    Bottom line, open fermentation poses some risks for infection but can produce an un-infected beer on both the commercial and homebrew scale with the proper precautions. But for a beginner, put a lid on it
  20. epk

    epk Initiate (171) Jun 10, 2008 New Jersey

    Stop confusing us with your technical jargon.
    CurtFromHershey likes this.
  21. yinzer

    yinzer Aspirant (219) Nov 24, 2006 Pennsylvania

    Sorry, but I don't have the best camera. Cantillion (and I hope that these post)

  22. quirkzoo

    quirkzoo Initiate (0) Jul 7, 2011 Colorado

    I am sorry, what I meant to say was:

    C12H22O11 +H2O + invertase →2 C6H12O6 + Zymase → 4 C2H5OH + 4 CO2
    josmickam likes this.
  23. hopfenunmaltz

    hopfenunmaltz Poo-Bah (1,826) Jun 8, 2005 Michigan

    The wort at Cantillon is in the coolship overnight, then gets racked into the barrels. Some debate how much of the magic comes from the open air in the urban environment of Anderlecht. The barrels are full of the organisms that do the fermentation and you can see the barm flowing out of the barrels there. Spontaneous fermnetation in that there are no yeast pitched.

    Many English, German and American breweries use open fermenters. Yeast is pitched, and the beer is left to ferment out, then racked to kegs or brite tanks. You can add Anchor, New Glarus (for the German wheat beers), and any brewery with an Alan Pugsly system to the list (Arcadia here in Michigan). German wheat beer brewers use open fermenters, as the Geraman wheat yeast strains don't benefit from pressure or high CO2 levels above the krauesen.

    One could leave the lid on the bucket loose, or put foil on the carboy neck to aid the CO2 exchange at the homebrew level. You could open ferment in a clean chamber or room if you have one, though the breweries have filtered air for ventilation. I have been thinking about feeding sterile filterd air to the top of my fermenter to see it there is any change in the finished beer, have the parts, but have not done it yet.

    There is a fun little movie on the Bigfoot page that shows an open fermentation.
  24. patto1ro

    patto1ro Zealot (566) Apr 26, 2004 Netherlands

    Every brewery I've been to in Franconia open ferments. Schneider has open fermenters, too.

    Open fermentation does not equal infection with wild yeast and bacteria.
    tronester likes this.
  25. patto1ro

    patto1ro Zealot (566) Apr 26, 2004 Netherlands

    The yeast used in Yorkshire squares is particularly suited to the conditions.
  26. OddNotion

    OddNotion Zealot (584) Nov 1, 2009 New Jersey

    No it does not, but on a homebrew scale in a house/garage the chances are heightened to the point where it may not be worth the risk.
  27. JackHorzempa

    JackHorzempa Poo-Bah (4,655) Dec 15, 2005 Pennsylvania

    The ‘trick’ for old school commercial breweries that perform open fermentation is to pitch a HUGE amount of healthy yeast. The idea is to ensure that the fermentation starts very quickly with the intended beer yeast so that you ‘muscle out’ any wild yeast or other microbes which may get in the wort. Commercial brewers can indeed ferment beer in open fermenters with very little noticeable off-flavors from wild yeast/bacteria etc.

    On the homebrew scale the open vs. closed fermentation is a classic risk vs. reward decision for me. Open fermentation represents nothing but risk to me with no reward that I can think of. On a commercial scale the risk vs. reward decision could be different.

  28. marquis

    marquis Champion (803) Nov 20, 2005 England

    Reverting back to so-called "spontaneous fermentation" eg for lambics it's about as spontaneous as getting your car spontaneously stolen by leaving it with the keys in the ignition in a city slum.Everything short of actually introducing the yeast is set up to happen , there are so many "house yeast" spores around that fermentation not only occurs but does so predictably. This isn't the case in a normal household.Just ferment in a bucket and if things are likely to fall in, cover with a loose lid.A blowoff tube is wasted effort. On an industrial scale the type of fermenter matters. I leave you with this article by Michael Jackson who knew a little bit about beer :slight_smile: Further reading;
    tronester likes this.
  29. Prostman81

    Prostman81 Aspirant (241) Sep 27, 2008 Illinois

    New Glarus does too with their Dancing Man Wheat
  30. telejunkie

    telejunkie Aspirant (259) Sep 14, 2007 Vermont

    one of my favorites was touring Magic Hat brewery (not the most respected among beer geeks) who have open fermenters and have never bought a new batch of yeast for their house ales...the have used the same strain since day 1 repitched thousands of times.
    To the OP, I would start with a porter. Regarding open vs. closed, I leave my lid loose on my bucket to check on fermentation and steal some krausen if I want. The I will usually seal the lid after maybe 72 hours of active fermentation. As said many times on this thread, won't make much difference on a hb scale either way.
  31. boddhitree

    boddhitree Zealot (555) Apr 13, 2008 Germany

    I took a brewery tour a month or so ago in Miltenberg, Germany at Faust Bauerei. I posted these previously on the German forum, but I found it was good for this thread, too.

    They had open fermentation these 8 feet deep Kuhlschiff (where we get the English word for Coolship), no windows, and surprisingly, they let us enter this room and hang out for over 15 minutes, the only stipulation being we shouldn't touch them or inside. Notice in the pics the metal pipes, which sucked up the CO2 in massive vacuums. Nonetheless, the lack of oxygen in the room still made up quite lightheaded.The room was built into the side of a sandstone mountain, which did wonders for temp control. This is all Pils, dark and lager. I was really surprised they let us in the room, and even more surprised they allowed us to walk up and down the aisle. Cheers.





    Here's the 200 year old cellar with an old lagering barrel.
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  32. LeeryLeprechaun

    LeeryLeprechaun Zealot (583) Jan 30, 2011 Colorado

    I agree. Not to mention the fact that at a brewery conditions can be controlled to help prevent infection via air filtration or closing the area off. That is a lot harder to do in your house which is not designed for open fermenting beer.
  33. ventura78

    ventura78 Aspirant (268) Nov 22, 2003 Massachusetts

    Chimay Red is a good example of this, it hasen't been the same in years
  34. hopfenunmaltz

    hopfenunmaltz Poo-Bah (1,826) Jun 8, 2005 Michigan

    Magic hat uses the Ringwood strain, right? They local brewpub used it for 300+ generations before they ordered a new pitch. Open fermenters, and skimed from the top.
  35. telejunkie

    telejunkie Aspirant (259) Sep 14, 2007 Vermont's a good top cropper, although personally not a big fan of the strain. I believe they'll give it an acid wash from time to time but that is about the only maintenance they perform in my understanding from the guide.
  36. epk

    epk Initiate (171) Jun 10, 2008 New Jersey

    Thanks for sharing, very cool pics!
  37. epk

    epk Initiate (171) Jun 10, 2008 New Jersey

    Ah, here it is -

    Only episode #4!

    And later, Jeremy King uses his open fermenter as a straight up coolship -

    I wonder how his brews from episode #4 turned out?
  38. patto1ro

    patto1ro Zealot (566) Apr 26, 2004 Netherlands

    Really cool photos. Love to see that open fermentation.

    But that isn't a Kuhlschiff, it's a fermenting vessel. A Kuhlschiff is just for cooling, not fermenting.

    I was shocked at how keen Lager breweries in Germany are on open fermenting. I'd naively thought that bottom-fermenting yeast didn't produce enough crust to keep crap out. As your photos show, there's plenty.
  39. boddhitree

    boddhitree Zealot (555) Apr 13, 2008 Germany

    You're right... I was watching TV while typing my original post... oops.

    Here's the site with all the pics.
  40. goodonezach

    goodonezach Initiate (0) Mar 24, 2011 New York

    magic hat could use another yeast strain or two...
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