Open fermentatio for weisse beer

I am not sure where to put this post so I am putting it here. I am reading all about how to do weisse beers and to accentuate the clove and banana and domy rest for 10-20min between 111-113 to produce the acid which will covert to the esters. Then I read about working with wheat and the classic beer style German Wheat Beer, and discovered the idea of doing open fermentation in tanks. Does anyone ever do this as a homebrew or is this something that basically has to happen in a clean room like setting?

Thanks,
~Ben

With reasonable sanitation, open fermentation is possible at home. The basic idea behind open fermentation is that the pressure is lower than in conical fermentors, and pressure affects how yeast behave and what byproducts they make. In a normal homebrew bucket or carboy with an airlock, I doubt the pressure is much higher than it would be in a bucket without a lid. So I don't think on a homebrew scale it makes much of a difference.

Kaiser did a test on a homebrew batch of weizen, one with a ferulic acid rest, one without, and he couldn't tell a difference in phenols/esters between the two. YMMV

Some brewers add a portion of dextrose because it accentuates either the clove or banana, don't remember which one.

I guess open fermenters also allow more oxygen to come into contact with the wort so there is more yeast growth which adds to the flavour.

Yea, I am willing to think that the pressure is a problem. I don't think it's an air in contact issue because the blanket of c02 is almost immediately produced and then you get high krausen etc. I do know that open fermetnation does produce different flavors with industrial fermentation tanks, but I don't know if it matters with home brew setups. Do closed fermentors have an air lock?

I am wondering if because a bucket has an air lock if it is considered an open fermenter. I could see that if the fermentation tanks don't have an air lock of some type that the pressure build up would be crazy and could easily affect the yeast.

Basically, I just don't know if this is something worth trying but I think I might just to have some fun with it.

Pro fermentors have airlocks, but they're pressure regulated. Most breweries ferment under pressure, some in the 15psi range, because more pressure means fewer esters/phenols, which means you can ferment at higher temperatures without getting over-the-top yeast flavor. Higher temps mean the beer is done and can be sold faster. So it's purely for economic reasons that they're fermented under pressure, not because it makes better beer.

Sierra Nevada is the notable exception of a big brewery that still uses open fermentors in the US. I've had their Kellerweiss, and while good, it wasn't head-and-shoulders above weizens from cylindroconicals.

Interesting. I think this is where I need to look at what gets me bigger marginal returns. I learned decoction mashing and I made the best heff I have ever had shy of wheinstephaner. Also I did the acid rest.

I wonder though if the yeast can get into the autostilys under such high pressure. I am sure that the big guys have all of that figured out but this just basically means that we as home brewers will never have this problem. Hmm... I think I will try to do an open fermentation and cover it with seran wrap loosely to make sure that dust and stuff doesn't get in and see if it actually matters.

Actually you answered one of my most wondered about questions, why is in in every book I have read, the huge guys can ferment out a 50 to 500 barrel batch of beer in like, 3 days... push it into holding tanks for a few days and bottle and ship in under a week. I had such a hard time figuring out how they did that without either producing huge amounts of off flavors or shipping it while it was still fermenting since it takes my beer about 7 days to ferment out and that is with proper pitching rates. When I wasn't doing starters it would take about 10 to 12 days.

I have a feeling though, that I can get a bigger marginal return by doing the 113 rest for 10-20min and decoction mashing and not worrying about open fermentation so if I focus on that method I will start to produce excellent heff.

I actually am very skpetal about people saying that the rest doesn't do much, I used the Bavarian wheat yeast strain which will produce some esters but not like the weinstephan yeast strain which goes nuts and I managed to get quite a lot of clove flavor but not overpowering of what would have otherwise been a fairly muted beer. I don't think I would have done the rest with the weinstaphan as it would have just been overpowering. I used that yeast before and while I liked the flavor profile, I love the bravarian strain, it seems to give a drier, maltier beer than the weinstephan which just kicks you with banana and clove.

Yep, yeast is more likely to autolyze under the pressure in a commercial cylindroconical, so in a non-pressurized system, it's not really an issue. White Labs makes a high-pressure lager yeast that can ferment in under a week. Pretty wild how fast the commercial guys can crank beer out.

I usually do a rest in the protein range when using that much wheat malt, and I get good results, but I'm not sure the ferulic acid rest, per se, makes a difference. The only way to really know would be to do several different batches with slightly different protein rest temps.