Fermenting question

I was talking to a lhbs owner today and he was telling me the new thing to do when fermenting is instead of putting a lid on my bucket with an air lock, is to put plastic wrap over the top held on with an elastic. I would tend to think this would work but was wondering if anyone had some insight into this before I tried this.

Why would this be better than a lid with an airlock? Did he say? The purpose of having an airlock is to give the CO2 somewhere to escape. Not sure if saran wrap and the elastic would do that.

Anything that stops dust or insects such as fruit flys from getting in should work for barrier purposes. For allowing the CO2 to escape..... I would think the saran wrap with a rubber band wouldn't be exactly airtight and would allow the gas to escape.

The only advantage I see over the lid is it's cheaper, no airlock needed, easier to clean when done and you can see the fermentation.

The only disadvantage I could see is if plastic wrap allows O2 to diffuse into the bucket. I doubt this is an issue, however, because of it's ability to maintain food freshness and the CO2 present is heavier.

The LHBS dude is right, for primary fermentation, all you need to do is keep the bugs and larger stuff from falling into the wort. A garbage bag over your fermenting bucket strapped on with a bungee cord is good enough to keep the fermentation clear, because the CO2 produced will blow the contaminants sky-high!

leave this lid resting on top, with the handle pinching it in place. but you can't stack em or move it violently!

I've read on the forums where somebody uses a clear plexiglass cover over the top of his buckets. I guess the idea is you can see when fermentation starts to subside, then put a real lid on, and bottle/keg in a few more days.