I've not made a Lager before, but I have 20 litres brewing in the spare room. Fermentation is ridiculously erratic - airlock bubbles are uncountable, and when opened, the beer is "fizzing" and moving like hot lava. I shouldn't have a problem with overflow because I've got plenty of headroom in the bucket.
Is this totally normal? Don't wanna ruin the carpets, you see