Trying My First Open Fermentation

Hi guys!

For a while now, I've been trying to really bring out the banana esters on my hefe. For the last few batches I have followed the typical methods (Ferment warm, proper yeast selection, Mash Schedule, etc.) and it's produced solid results but I'd like to take it a step further. To accomplish this, I'm considering doing an open fermentation in a differently shaped fermenter as is illustrated in this thread (https://www.homebrewtalk.com/forum/threads/open-fermentation-in-a-plastic-diy-coolship.484727/).

With that in mind, I am MORTIFIED about something nasty getting into my beer as I really don't want a sour hefe. I have heard that once fermentation begins, the odds of infection are slim but what precautions do you take until then? I plan to THOROUGHLY clean my fermentation chamber and ferment in there in hopes that the lid of my chest freezer will prevent bugs and other unwanted things from getting in but what else should I do? Maybe I can put something like sanitized cheesecloth loosely over the fermenter or does this defeat the purpose of open fermentation? Am I worrying for nothing? Any other thoughts?

Thanks in advance for the help!

Cheers!
Casey

 

I'd love to hear some feedback from those who have open fermented before and have a hold on it...
I won't do it (at least in my brew room... Mold issues).

In my mind... The purpose of open fermentation is for sour and funk and introduction of odd bugs and critters, which is why the Belgians do it that way (for the few that still do it that way)...

Any open fermentation should pick up a significant quantity of lactobacillus as it's very prevalent in the air... Lacto=sour..

If you open ferment in a closed and sanitized chamber it seems to me that's just a larger fermenter?

There are ways to increase ester production. You are specifically looking for isoamyl acetate...

You can under pitch the yeast.. Under oxygenate the wort...
Or raise the fermentation temperature but do it in the lag phase....

Start gentle and ramp it up.

There are a bunch of articles out there about increasing and controlling Ester production out there and if you open ferment... Better chance of losing the batch.

 

Open fermenting a hefe is a little bit more of a challenge because of the relatively low hopping rates. I open ferment all of my British beers, and they turn out really well, but they have a significant amount of hops to slow down any lacto.

That said, I have open fermented a hefe, but the problem is you have to pitch sufficient yeast cells to overcome any secondary infection but then you lose one of the ways of increasing esters, namely underpitching.

Knowing how many viable cells you are pitching is important. I use white labs for my hefe yeast because you can look up the cell counts on Yeastman and have somewhat of a ballpark idea of how many cells I have. I wish Wyeast would make cell counts per batch available.

I ferment my 5gal batches in a 30L speidel. This leaves me plenty of headspace for the top croppers to go crazy without making a mess. My open fermentation usually just means I don't put any liquid in the airlock for the first 5 days. This worked for my latest hefe open fermentation and it fermented clean. I have tried the cheesecloth over the larger opening, but got a lacto infection in the hefe I tried it with. Was quite a clean sourness and wasn't a bad beer actually, but it got dumped.

Best of luck.

 

I open ferment all the time and not just for Hefeweizen but Kölsch as well. It's less work for me because it's not necessary to oxygenate and I bottle spund straight out of the tank. The ferments always kick off fast. This is 12 hours after pitching 1 tube WLP300 which is definitely an underpitch in 6 gallons.



The yeast are very happy and this is about 26 hours in with a lot of them floating on foam bergs. Sometimes the ferment will stop unless they are stirred back in. This has been skimmed and roused once.



Usually only takes about 3 days before the beer has reached 3.5-4 points over terminal gravity and is ready to bottle. This is my solution to avoid contamination and works well.