Is anyone open fermentings these days? I've been interested in this practice but have always been worried about contamination mainly. I believe that some commericial guys still do this especially with thier ales. I'm even open to somewhat closed like in a HLT or Kettle with a lid. Anybody got experience with this please chime in or if there is already some info please direct.

I'm not sure which episode, but I know BrewingTV brewed a hefe open. They did a tasting a few episodes later and it turned out great.

I know there are some guys out there who ferment open (foil over the carboy or a loose lid on a bucket) for the first few days of fermentation to keep head pressure down. After the majority of fermentation (within 10 or so points of FG) they will put on an airlock to finish out. I've been thinking about going this way too to keep pressure strain off the yeast during the growth faze.

Give it a try, I know I will be.

I've never done it. I would love to have Mark Carpenter and the guys from Anchor back on the show to discuss open fermentation on the show.

As a side note, another story of Steam beer was in the original brewery they used open fermenters on the roof. They put the hot wort up there and let it cool enough to pitch the yeast. While it was cooling, you could see the steam rising off the wort on the roof, hence Steam beer. Head to their website and look at the Steam beer video. There's a few clips of what I'm talking about. Pretty neat.

I wonder how long the wort would be protected by the steam in that case. I think that would be really neat to have the shallow open fermentors like they talked about. Even something like the bottom of a plastic barrel like what I use to catch any blowoff from fermentation. It's 22 inches diameter and 13 inches high, which works out to approximately 4,944 cu in. There's 231 cu in in a gallon, so it can hold about 21.4 gallons. Might be good for a 10 or 15 gallon open fermentor. 15 gallon for normal yeast and 10 gallon for WLP300 batches.

I have open fermented 3 different beers so far. Belgian Patersbier with Wyeast 3787 Trappist, a Belgian Quadrupel with Wyeast 3787 and a West Coast Amber IPA with Wyeast 1099 Whitbread.

For the Quadrupel I chilled down the 1.080 wort, left it overnight from midnight to 10am then pitched the Trappist yeast in a 2 liter starter at 68 degrees before I left for work. I came back 10 hours later to find a thick 3 inch krausen. By day 2 my gravity had dropped to 1.043 and I had a 6 inch foamy krausen head that was slowly growing and overflowing out of the bucket. I forgot where I read this at (possibly the Wyeast website?) but if your krausen level gets too thick on the 3787 yeast it is recommended that you swirl your fermentation vessel around to break it up a little and relieve some of the pressure that the thick cap of yeast is holding.

All in all I had the fermentation open for 5 days mainly because I knew the Trappist yeast was going to make a huge mess in a standard glass carboy. Also Adam Avery mentioned having a strong pitch of 3787 for this so I figured a consistent supply of oxygen would help build up extra yeast. There was a point where the krausen level dropped back down to 2 inches and I thought it was safe to put the lid back on... turns out I was wrong. In the middle of the night the lid burst off and flung trappist yeast all over the walls and onto my bed where I happened to be sleeping. Talk about a rude awakening.

Once the krausen level was getting low, 2 inches give or take, I decided it was time to cover it up so I didn't get any further oxygen into my beer. After about 5 days I was down to 1.018 and still actively fermenting. A few days later I decided to move it to a sanitized carboy. I sampled some and it tasted very "Belgian-y" and raisiny but it was hard to detect to true flavor because there was a ton of yeast still in suspension.

Hope this info helps. Let me know if you have questions. If you decide to do this, whatever room you do it in will be overcome by the aromas of fermentation. Oh and I will say I didn't skimp on the cleaning or the sanitizing of anything before I used it. I treated the fermentation the same as I would for a normal closed fermentation.


Here are a few from the Belgian Quadrupel that I hope comes close to Avery's "The Reverend".


IMG_3242 by Afterlab, on Flickr



IMG_3255 by Afterlab, on Flickr


IMG_3247 by Afterlab, on Flickr

My goals were to be able to harvest some yeast and to see what effects the extra oxygen and the ability for the ferment to really breath had on a beer. Maybe I will try the same recipe open and closed for an experiment to see what comes of it. Will the CO2 from the yeast act as a buffer for the beer to keep out microscopic air born contaminates?

I suppose if you're on an all grain setup you can run off an extra few gallons of party gyle wort and use that as a sort of a throw away 2 gallon brew solely for the purposes of harvesting wild yeast. I've heard some people use a bucket with a mesh type bag on the top of it to keep large objects out of it. Then just throw that outside overnight and see what happens.

If you haven't already, check out episode 42 of Brewing TV. Jeremy King does an open fermentation in his garage with a koelschip setup sort of similar to that of Allagash. http://www.brewingtv.com/episodes/2011/ ... lship.html

HAHAHAHHAHAHAHA

If you are doing truly open, you are often looking for GOOD microscopic bits to fall in and get you some wild yeast stuff going on. I think it sounds like you are asking about two slightly different things (or at least getting responses on)

1. Open fermentation, where exposure to wild yeast strains is permitted
2. Zero head pressure fermentation, which Whitey and others have talked about as being better for the yeast. Once there is a good head of krausen, I doubt there is much oxygen diffusion down into the liquid portion of the ferment, any oxygen uptake via ZHP fermentation would likely be before or after it falls.