I love your innovation. A “chip sock” can be a real boon to winemakers. In fact, I mention using one in The Winemaker’s Answer Book where I suggest using a nylon stocking as a handy and cheap DIY bag. A small food-grade nylon bag, especially when it’s not as delicate as a nylon stocking, is an even better bet. Washable, re-useable, and more robust, this kind of submergible container for those pesky little chips definitely leaves less of a mess.
You’re right to question whether the extraction dynamics are different as a chip sock will keep all the chips together in one place rather than floating freely (or sinking) in the liquid. I actually prefer using a sock or some kind of bag rather than just having chips float loose on the surface. I believe that you get more of the wood submerged overall and it’s cleaner and safer for the wine. Basically, I consider loose, floating chips like little islands for bacteria and mold to possibly grow on. The underside of that chip will be wet and in contact with the wine; the low pH and lack of oxygen on the underside will help to keep spoilage organism growth under control. On the sunny topside, however, there’s no low pH benefit and it’s possible there’s quite an oxygen-rich environment if the container is not topped. That can easily become a recipe for trouble if not handled properly.
Furthermore, if you just have loose chips and a completely topped container like a carboy, most of the chips will just be floating up in the neck of the carboy, not really mixing and mingling with the rest of the wine. The best-case scenario is to use a chip bag but to submerge it with weights so it can float around the middle to bottom of your container. Depending on the size of your container and the chip bag (and the number of oak chips) anything from a few marbles to a few stainless steel tank fittings or washers could do it. If you are large enough to ferment in tanks, many tanks either have (or can be ordered) with D-rings welded inside. These are handy places to tie off your chip bags so you know they’ll always be safely submerged.
