After all of your bottles have been safely filled and corked, you can choose to put heat-shrinkable capsules (shrink-caps) over the neck of the bottle. While not necessary to preserve the wine, they give a nice finished look to your bottles, and when coordinated with labels give your wine a professional look. Shrink-caps are called so because heat is used to shrink the plastic onto the bottle neck, holding it tightly and smoothing out any wrinkles or seams in the plastic.
The best way to apply this heat is with the steam from a teakettle. At a rolling boil the teakettle will produce enough steam out of the end of it’s spout to shrink a capsule in only two or three seconds. Be careful not to burn your fingers! You can use blow dryers, but they are very slow. Hot air paint strippers work better, but they aren’t as fast as a kettle, and are a bit more dangerous to use. In a pinch, the heat from an electric stove element will also serve to shrink the capsules on, but again, be careful with a hot stove.
The safest method is using a Fast Seal Tool to hold the shrink-caps in place while you dip them into a pot of boiling water. There are special Hand Held and Bench Top Shrink Machines called Thermocapsulers(#7247). They will shrink the caps in one second, and are ideal if you are going to be sealing large amounts of bottles.
After sealing, you should leave your wine bottles standing upright for at least the first 24 hours. The compressed air has to work its way out past the cork, and it can only do that if the bottle is standing up. If you immediately turn the bottle on it’s side, the pressure will still be there, but the wine will now be pushing against the cork, and could force it out of the bottle.
After 24 hours (or two or three days: it isn’t critical to do it right away) you should turn the bottles on their side for long term storage. This is when the wine against the cork will keep it moist, preventing leaks.