I've had several batches of Mr. BEER come out short on abv by a few percent. I try to follow the directions religiously but some batches just come up very short. Most recently American lager, came out 3.57% after 16 days at 64-66°. I've had a suspicion that this is a yeast problem. I can see the yeast getting blown out by some if the high malt recipes but this one? I'm thinking old yeast. I brewed it within a week of receiving. Idk what do you guys think? Do you activate your yeast first?
I'm no expert, tastes "ok" to me, judging by your first response I may need to raise the temp though. The basement room is holding at 68.5 the two LBKs I have going right now are showing 68 to 68.5. My last 3 mixes came out with steady bubbles rising in the glass. Like I said, the rest of the bottles seem firm so I was surprised. I didn't actually squeeze this one before I opened it. Maybe it was just that particular bottle, I'll try another later today and see if it's similar.