Do natural cork stoppers allow air to penetrate?

A friend of mine is writing an article on cork stoppers vs. screw caps.

He has received conflicting information on the subject of whether or not natural corks actually allow oxygen exchange.

Can anyone help me to light his lantern, and prove this point one way or the other?

Thanks in advance,
Best regards,
Alex R.

A friend of mine is writing an article on cork stoppers vs. screw caps.

He has received conflicting information on the subject of whether or not natural corks actually allow oxygen exchange.

Can anyone help me to light his lantern, and prove this point one way or the other?

Thanks in advance,
Best regards,
Alex R.

Alex,

Others can speak about the permeability of cork in general, but I think the biggest factor is air going around the cork, the amount of which varies widely from cork to cork, depending on the condition, dimension and composition of the cork: Corks can of course deteriorate over time. The diameter of the cork relative to the inside neck plays a part. I have had entire cases ruined (oxidized) by corks having a 'plug' fit as opposed to a 'press' fit. Length of the cork matters: the shorter has not the sealing capability of the longer. Finally, cheaper corks are often harder, with lower sealing potential.

One can use a sex mnemonic which is however only two-thirds helpful.

Diogenes

Our good friend Jamie Goode, the Wine Anorak, has studied and researched this subject very intensely and has even writtten a book on the issue in question here. Click below for the link...............................

http://www.wineanorak.com/corks/cork_index.htm

Hi

This is not an answer but I'm curious about this too... Why are older bottles expected to have more ullage if there's nothing coming out?

Karl

The purpose of any wine closure is to prevent air from penetrating. Cork does this to greater and lesser degrees.

Be sure to read this:

http://209.85.165.104/search?q=cache:4fYmG763ON0J:www.awri.com.au/technical_review/technotes/AWRI_TechNotes_639.pdf+screwcaps&hl=en&ct=clnk&cd=1&gl=us