VBLs are basically a thin layer of plastic that can be worn directly on your foot OR more typically on top of a thin synthetic liner sock (no cotton!). The liner sock is then covered with your heavy weight wool or synthetic sock and the works are stuffed into your boots. The logic behind VBLs is that they lock in the moisture generated by your foot and don’t allow it to seep into your heavy insulating sock and boot liners. This is extremely beneficial, if you have feet that produce sweat by the bucketful! An added benefit is that your feet will actually stop perspiring when the area around your skin reaches 100% humidity. Something about osmosis, diffusion, semi-permeable membranes or some other scientific blather that frankly makes my head ache. Many sources will explain that VBLs will not necessarily make your feet “warmer” but instead will make them “drier”. However, a dry sock will keep you toastier longer as its loft will be maintained. For this reason, I add approximately +5 degrees F to the insulation rating of any boot system incorporating VBLs.
For those looking to try VBLs I suggest that before you jump on the internet and order a pair for $30 bucks that you try an experiment to see if you like the VBL system. VBLs are certainly not for everyone and some love em and some hate em. For the LOVERS they embrace all of the components mentioned above, dry feet and toasty toes. For the HATERS they complain about damp liner socks and feet that slide around in their boots worse than an Olympic slalom skier.
First visit your sock drawer and find a pair of thin SYNTHETIC dress sock. Put then on your feet and next get your hands on the wife’s oven roasting bags (chicken) or plastic bread bags and slide them on. Lastly, pull out your smart wool expedition weight socks and put them on as well. Throw the entire works into your favorite ice fishing or hunting boot and head out onto the hardwater or into the woods and see how it works!
For those of you brave enough to try my little experiment it would be great to receive a comment. An explanation of your experience (length of time out, temperature, etc.) would be great BUT for those short on time a quick response of LOVER or HATER would be more than sufficient! Thanks!