What The Cork

written by Lucy Munene 29th June 2019

We all have a love and hate relationship with corks. For some, they slip out of their favourite bottles, for others shoes, knives and hangers have been employed to coax them out and for a select few, ice has been placed on areas where bruises have been caused by poorly aimed champagne bottles. Cork didn’t always start off as a stopper though. It was used for floors, walls and even for fishing.

Fast forward to the 19th century and corks moved from just being used in champagne bottles to mass production and commercial farming of cork trees. As we moved into the 20th century, technology advanced and different types of corks were developed most of which are still in use to this day. You have definitely seen these different types of corks and wondered why some break apart and others don’t. We’ve broken it down for you so that the next time you open a bottle you know your tiny opponent a little better. 

Natural Cork

This is a blanket term for different grades and styles of cork made from natural cork tree bark.  These corks are 100% natural. It is a natural raw material which is extracted from the bark of cork oak. This material is impermeable to liquids and gases. In addition, it is lightweight, elastic, provides insulation, abrasion resistant, biodegradable, recyclable and renewable. 

One-Piece Natural

Similar to its name, made from one piece of natural cork, expands naturally and remains strong over a long period of time. It is typically used in high-end wines especially good for ageing wine long term. 


Made from two or more pieces of natural cork (that weren’t thick enough be used as a one-piece cork, usually have high density) that are usually glued together. Used for larger bottles (that don’t need ageing) when it is difficult to produce a one-piece cork.  


Made from one piece of natural cork however, the pores are filled with cork powder then kept in place by adding resin glue to form smooth and uniform corks. Typically used in young still wines that do not need to be aged for more than 3 years. 


Made from the leftovers of one piece cork production and consists of different quality levels of grain. In this case, products that are safe for contact with food are used to hold all the pieces in place. Better for younger wines not aged for more than 2 years. 

Technical/Twin top Agglomerated

Made up of agglomerated cork sandwiched between on or two natural cork discs on each side. They maintain the necessary sulphite concentration which prevents rapid oxidation of the wine. Good for wines that require medium ageing. 

Cava & Sparkling

These are similar to technical corks but are only used for sparkling wines and may consist of one, two or three natural discs of natural cork. 


Natural corks have pores that let in a certain amount of oxygen which is necessary when ageing the wine. However, trichloroanisole (TCA) leaks in as well and gives the wine a mouldy aroma known as cork taint. To prevent this, synthetic corks made from polymers filled with thermoplastic material were produced. Allow specificity when determining oxygen transfer which affects oxidation rate which means that taste can be predicted. Typically used in young wines (1 – 3 years), guarantees perfect compression, can be stored vertically. 

Screw cap

Made up of aluminium, these caps are popularly used in young white wines but they are now being used in other wines for medium to long term ageing. They are popular because there is no risk of cork taint, easier to open and allow the bottle to be opened and closed multiple times. 

Yummy tip:

Don’t judge a wine by its cover. Lots of fine wines come with screw caps so don’t skip a good looking Cabernet because it’s got a screw cap. 


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