This method has been tested with great success for tenting in Polar bear country in the winter time:

Take a bag-in-box of not too pricey, but otherwise good red wine of your liking. Tear off the cardboard and throw the bag into your biggest snowmelting-waterheating pan with lots of snow/ice and put it all on the stove. Pay attention when the snow is melted and the temperature starts to rise. Freshly boiled wine has its merits and followers, but carefully tempered is really the way to go. The exact optimum temperature is a topic of much heated debate among connieseurs, but in my opinion, anywhere from 30 to 50 C (86 to 122 F) is good. The more frozen you are the hotter the wine should be.


The lukewarm/hot wine bag doubles as tummy warmer for the most chilled person in the group. (More often than not, this will be a female - or did you forget to bring female companions?) Having a warm wine bag on your tummy not only brings physical warmth, but will also provide a lot of friendly attention from anyone who thirsts for a zip of nice, perfectly temperated red wine. This is good for the morale and companionship of the individual and the group.

Of course, if you plan on going swimming in those conditions then all these preparations should be done in advance.