Instead of using metatartric acid, we leave the door open during the winter.
What is the point of all these additives? Firstly, it is important to say that there is, at present, no legislation that requires producers to state on the label if there are any additives. However by November 2005, it will be compulsory to indicate "contains sulfites" on the label. As for any other additives, nothing.
Arabic gum: theoretically, this is to stabilise colour and prevent colour matter from depositing in the bottle. In reality, arabic gum is used to round off agressive green tanins that are the result of immature grapes. Gamay has a natural tendancy to produce high yields. Invariably, the temptation is to use arabic gum to cover up the thin, green aspect in the finished wine. Arabic gum is widely used through the wine and food industry. There is no legal limit to the amount that may be added to wine.
Ascorbic acid: better known as vitamin C. This is added to preserve freshness in wine. If the wine has been made from healthy grapes and handled correctly until bottling time there is no real need to add this . We have not noticed a lack of freshness since we stopped using it.
Metatartric acid: this is to prevent small cristals of tartric acid occuring in the bottle if the wine is exposed to cold temperatures. It only works for a few months after bottling. Wine labs commonly recommend adding it even during summer bottling. This is ridiculous as it will have no effect at all by the next winter.
At Domaine du Fontenay, no metatartric is used: we much prefer to precipitate as much tartric as possible in the vats during the winter by allowing the wines to get really cold (easy enough: leave the winery door open!). As it is not very common for red wines to get really cold after bottling, I have never noticed any cristals in the bottle, even several years later.
Copper sulfates: this is less widespread than the other additives, but still commonly used to prevent reduced smells occuring in the bottle. If a wine has not been allowed to digest the necessary amount of oxygen before bottling, it will tend to close up in the bottle and be less expressive or even"reduced"- smells reminiscent of egg or animal -
Wine can only digest oxygen at a temperature of 12°C or more. In order to avoid the closed-up reduced smell in wine, it is important firstly to provide the wine with sufficient oxygen during the fermentation period and secondly leave it for long enough in the tank during the spring before bottling as to warm up. Only attentive tasting can indicate as to when a wine is ready for bottling. Once the wine is in the oxygen-poor environment of a closed bottle it is too late. This is why we refuse to bottle too early. We would love some of our customers to understand this better!