Beginning homebrewer in San Jose here.
I have a 3 gallon FastFermenter that I am very happy with, but there is 1 thing I do not understand. I've been brewing 1 gallon kits from Brewmaster that I purchase at MoreBeer. I've lately been combining 2 of the same kit to yield a 2 gallon batch, which gives me 16-18 bottles. After chilling, I pour the wort into the FastFermenter, pitch the yeast, and wait. With this procedure, there is never any bubbling/activity at the airlock. I wait 2 weeks, then bottle the beer, then let it condition for another 3 weeks, then drink the beer. It is always good. I cannot measure the beginning and final specific gravity as my hydrometer tends to bottom out, so I don't trust the reading, and just use 2 weeks and 3 weeks as my milestones.
When I brew just 1 gallon, using a 1 gallon glass carboy for fermentation, there is always lots of bubbling, and in fact sometimes a mess to clean up.
So, is there an explanation for the lack of bubbling at the airlock? The beer tastes fine. Might it have something to do with the "headspace" between the beer surface and the lid of the fermenter? A gentleman at MoreBeer said I must have an air leak in the system, but I can find no evidence of that.