The colour of a bottle of wine is not only to prevent wines from oxidation caused by sunlight, but also due to others factors.
It is well known today that green glass is better at keeping sunlight out than clear bottles, but at the early stages of their use, people didn’t know about that.
The first glass bottles had the dark green colour due to the green smoke produced by the turf fires to heat and give shape to glass. As time went by, people realised that dark glass blocked out the sunlight favouring the natural antioxidants in wine to last longer, preserving it in better conditions and therefore, contributing to a better ageing.
Although protecting wine from sunlight is still considered a fundamental issue, nowadays the different colors of the bottles depend much more on marketing and economic criteria.
At present, green is often the cheapest glass in the market as its impurities do not need to be removed, nor needs to be painted. Clear glass bottles are usually preferred for white and rosé wines because, from a marketing point of view, consumers are more attracted to purchasing them when they are able to see their colour. Apart from that, these wines are supposed to be consumed shortly after their production, so preventing them from sunlight effects becomes less important.
In wine marketing, black bottles are commonly associated to high-quality wines as they look more elegant and contribute to give a higher quality appearance to the wine. It is true that black glass gives a higher protection from sunlight than green glass, but its high pricing with regard to green glass does not necessarily correspond to this protection factor.