13 July 2016

BOJ’s spiral helix or worms (1-2): Types of Corks

One of the goals that we have in BOJ since a long time ago is to create a worm (spiral helix) able to extract all the types of corks. Because of the great variety of types of corks there are, one of the most common question our costumers ask is, can your worm extract all kind of cork?

And so, after meeting with our department of i+D+I and learning about their studies and the papers we ask for to other institutions over the years for this subject, specially to improve the efficacy of the 110 model, we thought that we could also explain you about the types of corks that there are being use nowadays, and tell you of our investigations to create an universal worm that can extract any type of cork in a mechanical wall-mounted corkscrew.

 To simplify things in the wine industry, of which BOJ knows quite a lot, classifies corks in 2 principal categories, naturals and synthetics.

Natural Corks

As it should be obvious natural corks are made of cork, in other words, cork oak bark. Nowadays 80% of the wine bottles use these corks.

As extra information we could add that oaks and their production to get the cork are located in the Mediterranean, with Portugal as the greatest manufacturer, with approximately the 50% of the market, followed by Spain with 25% of the market.

Within the natural corks category we can make some new subcategories, that we can check in

  •  Naturals, those that are 100% cork oak bark
  •  Multi-piece corks, those with pieces of natural corks put together with adhesive that is approved to be use on food.
  • Filled corks, those in which their micro pores are filled so that the air can't enter the bottle.
  • Technical, those agglomerated corks with 1 or 2 circles of natural corks in the top and the bottom.
  •  Agglomerated, those made with agglomerate of cork oak bark
  •  Pro Cork, those natural corks that have been cover in up to 5 polymers to avoid, among other things, the problem of the TCA.

 For the wines that are meant to mature a long time a natural cork must be used as only natural corks allow the micro-oxygenation. While theses ones have the problem of the TCA, an aromatic molecule that sometimes appears in the oak and that in case of having it in the cork it may pass to the wine, giving it a disgusting bouquet. Approximately between 8 and 9 bottles per 100 bottles of wine will have the TCA problem. To avoid the TCA problem the synthetic corks were develop.

Synthetic Corks

As we said the synthetic corks were develop as an alternative to the natural ones because, among other reasons like economics ones, to avoid the TCA problem.

The synthetic corks are made by extrusion as well as by injection lately. They are made of polymers and thermoplastics that grant them elasticity and water proof sealing. The wine bottles with these corks can be stored vertically because of this.

The composition of the synthetic cork depends on the manufacturer, who keeps his secret formula secret. All of them must follow the sanitary rules and the demands of the wine makers that purchase their products, and that demand for them to not to change nor add any texture, bouquet or taste. But that every manufacturer has their own recipe means that every synthetic cork has a unique density, elasticity and consistency.

But not only the corks matter, when designing a good corkscrew and a good worm (spiral helix). In the next article on our blog will explain which one is the second point that our i+D+I took in consideration for their investigation: The method of insertion of the cork and the pressure of the cork.