So I know many of us like to ferment as cold as the yeast can take it - and I personally have made some of my best beers by doing this. A few particular ale strains seem to fare particularly well at colder temperatures: WLP001/Wyeast1056/US-05 makes great beer around 58F, Pacman seems to perform best at a 56-58F temperature, and Wyeast 1007 does especially well at around 52F. But I am wondering what can go wrong if you pitch way too cold.
The beer I have fermenting right now is an American Pale Ale. The recipe is slightly odd, as I had less 2-row than I thought I did, and replaced it with Munich Malt - giving me a grain bill about 65% 2-row, 31% Munich, and 4% British Crystal 65L. Otherwise, the recipe is pretty normal - a lot of Cascade and a fair amount of Summit, bittered with a little Magnum. The trouble was that the wort was at 68F when I went to bed, and so I left it in the fermentation fridge over night to cool down… but it was at 46F the next morning when I aerated and pitched a lager-sized dose of Pacman. I left the beer at ambient, hoping it would warm up to 56F quickly, but it didn’t… and fermentation began to show itself 24 hours ago at 48F, with high krausen happening now at 54F. Is there likely to be any problem with such a cold pitch and relatively long lagtime (and extremely cool fermentation temperature)? Or should I just accept that I am building up a cold-tolerant strain of pacman?