Chronicle “Little vocabulary of wine”
Cork or no cork? Chipboard or plastic? While the packaging of wine is in full questioning, the cork is also part of the equation.
Who hasn’t thrown away a bottle because of its corky taste? Between 3% and 5% of the bottles closed with the traditional natural stopper, made from cork oak, will “contaminate” its content. It is a molecule called TCA (2,4,6-trichloro-anisole) that gives wine this unpleasant taste. And in 70% of cases, it is mold contained in the cork that is to blame: “Once the molecule is present in the cellar, it stays, explains Sandra Davidts, who works for the biodegradable cap brand SÜBR. But it can also come from wooden barrels, and develop under certain conditions of humidity and temperature.
Without wanting to overwhelm this poor little cork, there are different types of cork quality; thus, the big houses will sometimes choose cork for their prestigious cuvées and other types of stoppers for their other cuvées, such as agglomerate or plastic. “It is obvious that the natural cork stopper has a certain advantage, in particular its aesthetics, explains Magali-Eve Koralewski, who works on communication for Vinventions (the second largest cork manufacturer in the world). But in terms of oenological performance, it is very heterogeneous. We have no way to control the oxygen, not to mention the problems related to cork taint.”
Biodegradable caps
Your bottle of wine last night was therefore probably closed with a polyethylene stopper, agglomerated cork, or even with a screw cap, which is not without posing environmental problems. Cork is perhaps more uncertain in terms of oenological performance, but as its material captures CO2 rather than producing it, it remains an interesting alternative to synthetic corks… A real dilemma, therefore, for conscientious producers who do not want to harm the environment or risk spoiling the quality of their wine.
The search for agglomerated cork stoppers without polyurethane glue, biodegradable and biosourced, which do not develop cork taint, is a passion for many researchers and companies. “We have a lot of new customers, small winegrowers who are looking for biodegradable materials, without turning to cork, says Sandra Davidts. The very shape of the cork means that its decomposition will be very long, but if you crush the cork and put it in the compost, it is biodegradable. There are other corks created from sugar cane which, once transformed into polyethylene, will form recyclable but not biodegradable synthetic corks.
This is all the more important as the cork influences the way the wine will evolve over time. Because what transforms its taste, its color or even its texture, with more or less melted tannins, is notably linked to the oxygen level in the bottle. There are therefore permeable plugs that allow producers to control the amount of oxygen that will penetrate from the outside to the inside of the container. Will the wine that leaves the estate have to be kept for a very long time before being consumed? Or on the contrary, would it be preferable for it to be slightly in contact with oxygen to evolve quickly and be appreciated in the months following its bottling? That’s the question.
To check if the impact of the cork has a real effect on the wine, we carried out a fun test with two Bandol rosés from Château Val d’Arenc 2019 (80% Mourvèdre, 10% Grenache, 10% Cinsault) bottled the same day, i.e. March 1, 2022. The first had been sealed with a very airtight cap, the second with a more permeable cap. We tasted them a year later to judge their development. In the first bottle, on the nose, we find vegetal notes with hints of grapefruit and lemon and, on the palate, a lively astringency. The second bottle, closed with a more permeable cork, had developed aromas of apricot and peach during the same period; the wine was much rounder, more sensual, with an impression of fat. Without saying that it had oxidized, its content had evolved differently, and certainly faster than the previous one. Thus, depending on the cuvées and the type of market, the winemaker still has a small power over the evolution of his wines, even when they have left his estate and travel far from him.