I tend to think, P-Man, that this phenomenon which you've described is something witnessed only after several UNFROZEN beers are consumed. I think some rigorous testing is in order. I will be happy to act as the control for this experiment, and volunteer to sit in your passenger seat consuming Pabst at 34 degrees F at the same rate that you consume beer cooled to 30 degrees F.
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Consecutive posts mergedP.S. - I think the liquid you're seeing is alcohol and other chemicals with a lower natural freezing point than water. The water is very likely frozen, and due to the property of H2O to expand in solid form, the bottle is under pressure--ergo, explosion upon opening, messy steering wheel, and looking like you peed yourself. So I will open the beers while you drive.