Once a year or so, one of my winery club shipments bottles is a "reserve bottling" with a wax covering. What is the point of this? Is it just to look special, or does the wax insure the proper aging medium? I assume the former and not the later.
This is a more serious question than prior responses indicate.
The "aging medium" will be different, insofar as with the wax capsules there is likely to be zero or little transpiration through/around the cork, zero or little pressure equalization, and therefore greater and faster reductive reactions happening. There is also likely not to be any appreciable cellar mold or loss to rodents.
I'm not aware of anyone having really studied this.
It's my usual practice to wax-seal my large format (3L and up) bottles, why, I'm not sure. So far--from 2009--I'm not tasting any differences. IMO, there's a bigger difference from argon-sparging the bottles and headspace prior to corking, but my experience is mostly in the 750ml bottlings.
For another serious answer, l was told many years back that the use of wax was to prevent small creepie- crawlies from entering the corks, when metal capsules were developed the wax was no longer necessary as while very attractive served no additional function.
l used to wax my fave bottles as well, then stopped as it is such a mess when removing in a dining room situation whether at home or in restaurant.