Ever since I built a fermentation chamber out of a mini fridge last fall, I've been brewing a lot of lagers. I usually use Wyeast 2206 or White Labs WLP830 to ferment and I typically ferment between 46-50 degrees. I've been extremely pleased with the lagers I've brewed over the past few months, but I've been surprised how much less fermentation activity is evident in lager fermentations as compared to that of ales. This is probably to be expected given the lower fermentation temperatures, i.e., the yeast don't groove as hard in the cold.
Right now, I'm fermenting a 1.069 Maibock with WLP820. According to Mr. Malty, I pitched an adequate slurry from a previous batch (schwarzbier) and I aerated the crap out of it with my mix-stir. Pitched at 44 and it seems to be happily fermenting between 46-48 now. Despite visible signs of fermentation (as seen through the wall of the glass carboy), however, the airlock is only bubbling once every 10 seconds or so. At most, the airlock only bubbles at a rate of once per every 5-7 seconds for my lagers. Is this pretty normal for lager fermentations? Like I said, I've been extremely pleased with my lagers thus far (and that's what really matters), but I'm just curious about others' experiences.