Vintner's Harvest Premium Wine Corks



Wine Cork History

In the 1600s a Benedictine monk named Dom Perignon observed that wooden stoppers wrapped in oil-soaked rags used to seal his bottles of sparkling wine often popped out, and so he replaced them with conical pieces of cork. The world’s first cork stopper factory opened in Spain around 1750. 

Cork is harvested from the Cork Oak tree (Quercus suber) and sourced primarily from Spain, Portugal and Northern Africa.  Currently Portugal is considered to be the world’s leading producer of premium corks.

The bark of a mature cork tree is harvested just once every 10 to 12 years.  A cork tree is not regarded mature enough for it’s first bark harvesting until it is at least 25 years old, and the bark itself is not suitable for wine corks until the third harvest. A cork tree will yield 13 to 18 useful harvests in its lifetime.

Harvesting is still a manual operation with a special ax to cut into the bark and then they use it as a lever to gently pry the cork off the tree. The cork is peeled off in large panels from the main sections of the trunk, including the large branches. About a third of the bark can be harvested from the tree at one time. Cork harvesting is done entirely without machinery.

The processing of cork oak bark includes repeated sorting, boiling, punching, slicing, polishing, washing, drying, finishing and wax coating, and takes about a year.

Cork’s cell-like structure (there are around 800 million cells in a single wine cork) makes it the best sealing material for wine bottles. 

Corks are available in a wide variety of compositions, styles and sizes and it’s important to choose the best corking method for each type.



The Natural straight wine cork is a cylindrical stopper punched directly from the cork, manually or automatically. It is a 100% natural product.  The corks are then sorted by an optical cork sorting machine, before being washed using a hydrogen peroxide based solution. They are then dried and sorted manually into finer classes. The process ends with branding in accordance with the customers’ specifications and a surface treatment suitable for the intended use.


The Colmated wine cork (also known as the Bellcork)  is made of natural cork and then treated with a colmated process which involves a glue used to combine cork particles to fill the outer imperfections of the cork.  This process combined with the surface treatment gives the Bellcork cork improved sealing ability. Usually comes with a beveled edge.


Agglomerated corks are made from chipped cork pieces ground to a specific size and glued together with non-reactive polyurethane glue. Inexpensive and easy to handle, these are suitable for wines that will be held for six months to a year.  Agglomerate corks have high resilience and offer a good seal. Usually they come with a beveled edge.



Synthetic corks are made from inert synthetic resins, some wineries have tried them, mainly for short-term wines. They have to be put in with a heavy-duty corker, and can only be extracted with a good worm-type corkscrew wielded by a strong hand. Further development is needed before the home wine maker could put them to use without the use of a floor corker. Nomacorc is the exception as it is made from an extrusion process with uniform ,small closed cells that provide a superior seal to traditional synthetic corks which are molded.


There are several things to consider  when selecting the right cork for your purpose and cellaring conditions.

Estimate the length of time you realistically expect to store your wine before drinking.
This is the tapered edge that some of the less expensive corks have around the top and bottom of the cork. It is to allow easier insertion with hand held corkers. Take into account that  the bevel does reduce the amount of surface area in contact with the neck of the bottle and it is this contact that prevents the passage of wine past the cork.


Primarily  wine corks are available in two lengths – 38mm (1.5 inches) and 44mm (1.75 inches) – and in three diameters – 21mm, 22mm, 24mm (in USA and Canada they are known as #7, #8 and #9).  The length  and diameter  are related  to the sealing ability of the cork.  Where you compare corks in the same grade, the cork  with the longest length and largest diameter  will give the greatest sealing capability.   Floor corkers can be used on all corks, but if you are using plunge or hand corkers you may need to opt for the narrower and shorter corks. 

Remember … 
The cheapest cork isn’t always the best deal, and if you do decide to keep some bottles for the future, you may find yourself having to re-cork them in a few years.