I was curious as to what others use to keep out flies and still let material off gas during aging/tainting/etc. I know you can use an air stone or fermenters’ air locks but wanted to see if there were any other methods used with good luck by others.

We have been using the valve stem system for about 14 years now commercially. Previously we did the same thing using small lengths of clear plastic flexible tubing. Then I experimented with the valve stems and never went back. This method keeps your lids intact and allows for stacking if needed.

Remove the valve core with a core wrench and replace the cap loosely. This allows gas to escape and keeps flies and gnats out. Drill a 1/2" hole just below the lid bucket area and pull your valve stem through the hole until it pops into place. We stack 4-5 buckets high in our facility. Really saves us a lot of space. We have hundreds of buckets fitted this way and reuse them annually.

I had seen where you mentioned that in another post and was curious about how you implemented it. That is really helpful and simple. I appreciate it.

Gallon glass jars with a bread bag stretched over them push all of the air out then tape the bag to the jar.

Hint flies don’t work in the dark I have a small room with no windows that works like a dark room.

Didn’t know the bit about the flies and darkness, that’s a good thing to know

Only yellow buckets work.

Gallon glass jars with the lid loosely on and an old t-shirt or chunk of sheet tied around the rim. Trying five gallon bucket with airstone now, but only had it going for a few days so I can't report on how it works. I have the five gallon bucket covered with a black garbage also, which should keep most flies away, but is primarily to add heat from the sun.

1/2 gallon mason jars with the lid removed and hunk of t-shirt screwed down. Then another piece of t-shirt on top held down with a hair tie. Then I cover 6 or more at a time with old fish tanks I garbage pick

Lots of good information, thank you all

no blue does too

Thanks a bunch for this post. Worked perfectly. Didn't stop the stink though. Wife still made me take the buckets off the deck before guests came over. Oh well.

Remind her that she agreed when she married you that it was for better or worse.

Your right John, Blue sure does attack Blow flies.