Sparkling and semi-sparkling wines closure

What makes the difference among still, semi-sparkling (Frizzante) or sparkling (Spumante) wine is substantially the different quantity of carbon dioxide (CO2) dissolved in the wine: the bubbles.
According to Italian legislation, a wine is defined still if the overpressure is less than 1 atmosphere (bar), semi-sparkling if it is included in a range from 1 to 2.5 bar and sparkling wine if it exceeds 3.5 bar.

Generally the semi-sparkling wines on the market have at least 2 bars and sparkling wines 4.5 bars and more. It’s clear then the cork has to avoid the release of carbon dioxide (or we’ll found a degassed wine) guaranteeing the seal of the internal overpressure due precisely to CO2. Corks for semi-sparkling and sparkling wines must therefore have particular characteristics both of shape and elasticity.

Also the shape of the bottle (and mainly of its neck) plays an important role in the corking of the wine “with bubbles” therefore, especially in the capped flush semi-sparkling wines, the bottles whose neck widens downwards are generally preferred, as they help blocking the cork pushing up by the internal pressure. A typical bottle used for semi-sparkling and sparkling wines is the champagnotta bottle (à la champenoise).

In sparkling wines, the cork used is obviously the Champagne cork. This consists of two parts, the body and the head. The body is the part of the cap that is introduced into the neck of the bottle.
To be inserted, the plug is first lubricated and then compressed in order to reduce its diameter. Subsequently it is inserted into the bottle for about half of its length. The head is the part of the cap that comes out of the bottle and is anchored to the neck by the metal cage (gabbietta), which is also a fundamental part of this capping system.

A small mention should be made for the plastic Champagne caps with relative cage. These ones do nothing but emulate corks, but having less resistance to pressure and much less “grace” compared to the traditional closures, they are used for semi-sparkling wines and cheaper sparkling wines.

In semi-sparkling wines, flush capping is often used and the cork is completely inserted into the neck of the bottle, so that the use of a wire cage is not required. This can only be done in semi- sparkling wines because with the pressure of a sparkling content the “flush” cork would be irremediably shot out.

Finally there are the crown caps. These are often used to close some semi-sparkling or sparkling wine made using the ancestral method. This type of cap consists of a metal capsule that clings to the mouth of the bottle. Under this, a plastic gasket or a bidule provides watertightness. It can be fixed by a manual or pneumatic capping machine.