Will sports drinks freeze more slowly than water? I'm going into the mountains and would like to freeze-proof my beverages.
Pat Bagley, Weston, Massachusetts
Any substance added to water will lower water's freezing point because the molecules of the introduced substance displace those of water. Adding sugar or salt, the two common ingredients in sports drinks, to water will lower water's freezing point. Seawater, for instance, because it is loaded with salt, freezes at 28.4 degrees F. The freezing point for sports drinks is impossible to know because it depends on the quantity of the added ingredients. We know that for every five parts per thousand in salinity, the freezing point of water drops .5 degrees, but spiking your water with enough salt to keep it from freezing would make it nearly as toxic as a bag of fries from Micky D's. For the best possible result, go with the sports drink that boasts the highest, though still safe, concentrations of salt and sugar (higher concentration equals higher displacement of water molecules). From practical experience I can say that Gatorade and its ilk won't significantly lower water's freezing point, and in bitter temps of, say, 20 degrees F or colder, your water will freeze regardless. Then, take a lesson from Tom Patey and dispense with water altogether. Laphroaig, a peaty Islay libation, has a 40-percent alcohol content that remains liquid all the way down to -82 F.
Tip: Large bodies of water such as lakes freeze more slowly than smaller bodies such as puddles. Choosing a larger water bottle over a small one is a good idea, as is stowing your water bottle deep inside your pack, snugged nicely within a duvet, bag or extra clothing.