Cwdjrx _ wrote:
> Teflon has been long
> used and is very safe and non toxic for contact with foods and has been
> so approved. In fact many of you are drinking water that comes in
> contact wth Teflon. Teflon tape now is often used to seal the threads in
> plastic cold and hot water pipes that now serve most homes. Of course
> there are still a few homes served by pipes of the very natural material
> lead, and also a pipe cement containing lead oxide often was used before
> Teflon tape became common. A high quality screw seal with a Teflon
> insert for the seal probably would be best made of stainless steel that
> will withstand extremely long storage under damp conditions. Aluminum is
> much more reactive. The cap should be strong to avoid distortion by
> blows that can break the seal in soft, thin metal screw caps. Also the
> cap must be tightened to a sufficent pressure to hold the Teflon seal
> very tightly against the glass.

Teflon is certainly unreactive enough, but it might be too plastic to
keep a tight seal. For instance, the teflon tips to the plungers of
Gastight syringes that we use will deform enough if the plunger is
stored in the barrel to abrograte the seal of the syringe (that seal is
quickly restored by banging the plunger tip on a countertop several
times -- very plastic indeed). That happens over the course of a few
days, so a Teflon-lined cap would surely deform and possibly lose its
seal during the time needed to age wine.

Mark Lipton