***Thread Update Below***
I brewed "Pliney the Elder" on Saturday with some friends. Its target OG was 1.072. My actual gravity prior to pitching (assuming the wort was mixed well enough for the reading) was 1.062.
I had made my yeast starter (White Labs California Ale Yeast - liquid WLP001) on Thursday night (about 40 hours prior to pitching), using a two-liter bottle, the yeast and about 300 grams of Light DME, and put a tin foil hat on it. While it's the first time I've made a yeast starter, it seemed to work fine: I could 'hear' it sizzling like soda, I could see it fizzing, there was about 1/2 inch to 1 inch yeast settlement in the bottom of the soda bottle and I could visually see yeast clouds in the starter. I had also given the yeast starter bottle some light agitation every time I walked past it (maybe 6 times between starting and pitching.
After pitching at 68F, and holding the fermentation temp at 68, within 12 hours I noticed my blow-off tube bubbling -- not extremely vigorously, but well enough to suggest that fermentation was going well. However 12 more hours after that (24-36 hours after pitching) the blow off tube completely stopped revealing any activity. I've given it some extra light-agitation (simply by rocking the fermenter around), but there is still no apparent activity.
While I realize that lack of blow-off tube activity doesn't necessarily indicate a stuck fermentation, when should I start taking gravity readings to find out? I'd rather not fiddle with it if I don't need to... but if it is stuck I'd like to get it going in asap. I have another identical yeast vial in the fridge that could be used...