Steve Slatcher > wrote:

>> Besides the problem of corked wines, this failure of the cork
>> structure with extended contact with wine is the reason I hope
>> screw caps soon become universal. However I want a heavy duty
>> cap that will not bend or dent and that has a Teflon seal so
>> that the cap can withstand minor rough handling and can seal
>> for many decades without problems. Of course the present screw
>> caps may be good enough for wines not kept for several decades,
>> although the weak construction of them sometimes allows the
>> caps to dent or bend and leak if the cap receives a blow.
>> Surely a top, or even average, classified wine estate could
>> afford to pay a little more for heavy duty screw caps,
>> consdering the very high price their top wines now bring.

> Good point about the physical strength of the screwcap.
>
> I am not sure about tefon as a sealant though. I believe the
> current sealant disks (silicone I think) are carefully designed
> to perform their function, and there is even research to design
> seling disks that are slightly porous - in case people
> eventually decide that is desirabe.

The liner is made from 4 layers. From outside to wine

- the screwcap itself (aluminium alloy)
- a compressed wad of expanded polyethylene
- a tin foil (gas barrier)
- a neutral PVCD (polyvinylidene chloride)- not silicone! -
foil in touch with the wine.

See the details of the makeup he

<http://www.screwcap.co.nz/grids/index_green.asp?area=5&id=246>

Btw, current screwcaps have proven successfull in sealing over
more than three decades.

M.