Fermentation without an airlock

[Shaddapo]

Hello
I've been homebrewing beer kits for some years now and quite often during the early stage of vigorous fermentation the wort would bubble up through the airlock and make quite a mess. I never bother taking SG readings. Recently I've been leaving out the bung and airlock and just putting a piece of kitchen towel over the hole in the lid. I always leave it for 3 or 4 weeks before bottling. I find the beer fine but is it ok what I'm doing? I no longer have a mess from wort bubbling up thru the airlock and causing a mess. But is it ok for air to pass in and out through the kitchen towel to the beer?
Thanks guys.
Regards
Don

 

[JamesMcS]

The yeast will form a layer of co2 on top of the brew which, if not disturbed, will protect it from anything unpleasant.

You might want to consider a blow off tube - I use the bottom half of a 3 piece airlock, some siphon fluid and a jug of sterilising fluid for most of my beers now, just in case...

 

[Slid]

You could consider only putting the airlock in once the initial vigorous fermentation has passed, say after 3 days.