Storage for 1 - 6+ years These reference 1 corks are the traditional bottle closure for wine intended for longer term maturation and storage. A silicone coating on the cork reduces the drag when it slides through the corker. Newly purchased corks in an unopened park don't require sterilisation. To soften the corks for easier insertion by manual corkers only then place the corks in a colander over a bucket and allow boiled water vapour to rise up through the corks for a few minutes before using.