I've been intrigued with breathable silicone bungs for quite some time. They (upper picture) are supposed to allow dissolved CO2 and other gases slowly escape from the wine, while not allowing air (and dreaded O2) back in. Now, the water-filled airlocks (lower picture) do the same thing, although if there is a change in the barometric pressure when a storm comes through or winter slowly turns to spring, the wine can shrink in volume and suck water back into the wine risking bacterial contamination. Plus, you do have to keep an eye on the water level in the airlock to make sure that it doesn't evaporate below the entrance and let O2 into the carboy.
I've heard good things from folks who have used the breathable silicone bungs, so I've been wanting to purchase some. Only problem has been that every time I got serious about placing an order, Valley Vintner was out of stock and back-ordered. My luck changed a few weeks ago and they were in stock when I needed to purchase supplies for the upcoming Chilian grape season. So I bought some!
I decided to give one a try last weekend when I racked the 2008 blueberry off the lees layer. Instead of an airlock, I rammed in a fancy new breathable silicon bung into the carboy. So far, so good. A warm front came through last night and the the pressure differential in the carboy and the atmosphere pushed the bung slightly out. Not enough to break the seal fortunately, so I pushed it back in and adjusted the moveable flap to allow less pressure to move it.
This is something that's going to take a long time to evaluate whether I want to completely switch from the airlocks to the breathable silicon bung. In the meantime, I certainly do enjoy some new toys and feel like I'm living up to my chemistry background by utilizing products that could only be produced by a chemist. OK, I suppose a chemical engineer could come up with this as well, but it would have been a stretch!
Apologies to all you chemical engineers that just so happen to read this blog....
a Wine Student.
p.s. You know, the pictures looked just fine on the camera, but man are they dark! I'll have to take new brighter pictures and replace these.