Open fermentation & Why ?

[Majed41]

I saw a documentary last night from Germany where a Beer brewery does Open fermentation . with all O2 and the Bacteria in the AIR how this not ruined and no they didn't mention anything about filtration ? it goes against every thing we learn here as newbie . what we missing ?

also what' the point of Open fermentation ?

 

[hotbeer]

It a age old process that some are still able to do successfully.

I don't don't see it any different than any of the other processes we use to make beer. It just a tool or option that someone can choose if it fits their desires and works in their environment.

 

[odie]

been done for thousands of years.

now I wouldn't try it next to the local dump or sewage plant or in a big city with smoggy air...

If you lived out in the country I'd give it a shot.

 

[Cheshire Cat]

Open fermentation happened in the UK big cities with insanitary and smoggy conditions for hundreds of years. However maybe the drinkers weren’t that bothered then.

 

[@RoyalGallon]

In the 90s I worked at Cannon brewery in Sheffield UK. All the fermentation there was done in open squares - basically massive SS swimming pools.

The danger was the rooms that held about a dozen of these would soon be full of CO2 so sampling the FVs was dangerous.

In terms of location it was bang in the middle of one of the most industrial areas of Sheffield surrounded by dirty industrial factories. No issues for the beer with this!

 

[whattabrau]

I feel that open fermentation improves yeast expression, though I haven't done side-by-side comparisons for the same batch. Plus, I top-crop yeast when possible, so open fermentation avoids having to opencloseopenclose.

Also, open fermentation [at least in theory] improves the supply of oxygen to yeast. Remember that yeast needs oxygen, and that the saturation level of oxygen under atmospheric conditions is about 8mg/L and only about 12mg/L with an oxygen wand. Since the oxygen gets consumed in a few hours after yeast pitch, allowing 24-48h for more oxygen intake with open [pre-]fermentation will [likely?] result in a greater total amount of oxygen than from a single dose of pure oxygen. You'll notice the effect of oxygen and open fermentation easily with something more nutrient starved than beer, e.g. wine.

You are correct in that eventually O2 will spoil things. The trick is to either drink the beer before it spoils (a few weeks) or ensure all oxygen is purged while there is still active fermentation and no new oxygen is allowed enter.

Beer does not get infected as easily as we're led to believe. I have a few yeast strains approaching 2 dozen repitches. They've been open-fermented and top-cropped, and apart from having to start adding zinc at around generation 10, they work more or less like out of the packet. (yes I have managed to infect some yeasts, namely closed-fermented ones)

tl;dr prevent air contact starting at the tail end of fermentation, and you're fine

 

[chthon]

I half open ferment my beers, I stretch a cheese cloth over the top of my fermentation vessel, and keep it in a clean room out of the way of air currents. I have the impression my yeasts work more vigorous.

After 8 years of brewing, I have the impression that brewing beer is a more resilient process than people would make you believe on the web, and less prone to contamination and oxidation (perhaps some styles more than others) than is generally told.

Work clean and careful.

Also, in a real brewery with open fermentation, they pitch active yeast immediately. Airborne contaminants don't get the time to wake up in the fresh wort.

I do move my fermenting beer after four or five days to a closed vessel where the fermentation can drive all oxygen out.

 

[hotbeer]

I think most all the breweries that do open fermentation move the beer to a bright tank or other storage when fermentation is nearly complete and the krauesen foam is beginning to subside and expose the beer to air.

Exposure prior to the krauesen isn't an issue.

 

[tdf]

There's a nice blog post from Anchor brewing about their open fermentation:

Open Fermentation | Inside The Process at Anchor Brewing

Discover the heritage of our open fermentation process at Anchor Brewing - the only American brewery that still employs open fermentation on a commercial scale.

www.anchorbrewing.com

 

[cire]

I open ferment, I have to. Using traditional British top fermenting strains, fermentation vessels would need to be 3 to 4 times the wort volume to keep the yeast within bounds. Open topped allows heat to escape and significantly reduces the volume needed for beers brewed with many traditional yeast that provide flavors other yeast cannot.

 

[patto1ro]

I feel that open fermentation improves yeast expression, though I haven't done side-by-side comparisons for the same batch. Plus, I top-crop yeast when possible, so open fermentation avoids having to opencloseopenclose.

Also, open fermentation [at least in theory] improves the supply of oxygen to yeast. Remember that yeast needs oxygen, and that the saturation level of oxygen under atmospheric conditions is about 8mg/L and only about 12mg/L with an oxygen wand. Since the oxygen gets consumed in a few hours after yeast pitch, allowing 24-48h for more oxygen intake with open [pre-]fermentation will [likely?] result in a greater total amount of oxygen than from a single dose of pure oxygen. You'll notice the effect of oxygen and open fermentation easily with something more nutrient starved than beer, e.g. wine.

You are correct in that eventually O2 will spoil things. The trick is to either drink the beer before it spoils (a few weeks) or ensure all oxygen is purged while there is still active fermentation and no new oxygen is allowed enter.

Beer does not get infected as easily as we're led to believe. I have a few yeast strains approaching 2 dozen repitches. They've been open-fermented and top-cropped, and apart from having to start adding zinc at around generation 10, they work more or less like out of the packet. (yes I have managed to infect some yeasts, namely closed-fermented ones)

tl;dr prevent air contact starting at the tail end of fermentation, and you're fine

Harvey's open ferment and have been repitching for over 60 years. They must be on generation x million by now.

 

[Oleson M.D.]

The folks at Altstadt Brewing employ open fermentation with some beers.

 

[mac_1103]

Harvey's open ferment and have been repitching for over 60 years. They must be on generation x million by now.

I realize this is hyperbole, but...

60 x 365 < 22,000

And it seems unlikely that they ferment in one day and repitch one to one. Probably more like generation 200 depending on when they crop and how much they scale out.

 

[Nixter]

Belgium sours are also open fermented. It's not just the wild airborne yeasts contributing to the flavor its bacteria too. The beams of those Trappist monasteries are a bacterial gold mine.

 

[Clint Yeastwood]

So what about making 5 gallons of wort and leaving it in the backyard without pitching to see what happens?

 

[OleBrewing]

my grandpa told me his uncle used to make great beer out in the ND prairie, they would dig out a hole in the ground in a shaded area of trees and brush. put the vessel in there with cheese cloth over top. not sure on their bottling process or style of beer, and this was back in the early 1900s and descendants of Scandinavia. i am sure it was interesting beer.

 

[chthon]

Belgium sours are also open fermented. It's not just the wild airborne yeasts contributing to the flavor its bacteria too. The beams of those Trappist monasteries are a bacterial gold mine.

The trappists don't brew lambic, only some commercial breweries around Brussels.

And I hate the term "sours" or "sour beer", this implies acidity, but good lambic, gueuze or derived fruitbeers are not sour or acidic, at most a bit tart.

 

[chthon]

So what about making 5 gallons of wort and leaving it in the backyard without pitching to see what happens?

Yep, homebrewers on the Continent and UK do this. But you better split the 5g up in different small batches, and use them as starters after asessing their qualities when fermentation starts.

And only after summer, Sep-Oct.

 

[shetc]

I do a kind of open fermentation for saisons as described by Drew Beechum. A data point in this exbeeriment suggests a detectable difference for closed vs open fermentation:

exBEERiment | Impact Of Open Fermentation On A High OG Saison

Author: Matt Del Fiacco Fermentation generally occurs in a vessel that gets closed off from the outside world with an airlock or blowoff tube, which restricts the ingress of unwanted beer spoilers …

brulosophy.com