The volume of 75cl was standardized in the 19th century. At that time, the biggest clients for the French wines were the British.
The close neighbors do not use the metric system and used to order wine in “imperial gallon”. One gallon is about 4.546 liters.
Barrels were used to transport wine at that time. One barrel is 50 gallons, about 225 liters. A real nightmare for conversion! So to ease the calculation, the wine makers from Bordeaux decided that 1 barrel would be 300 bottles of wine instead of 225.
So, to put 225 litres in 300 bottles, each bottle needs to be 225/300 = 0.75L, or 75cl!
Moreoever, one gallon is 6 bottles, and since then, that’s the reason why we still order wine in packs of 6 bottles.
But I'm sure you've already seen huge bottle sizes in the past, and you're wondering how that's possible.
Here is the complete understanding of all bottle sizes.
In fact, every bottle is calculated on the basis of a 75cl bottle, and has its own name.
When I was visiting caves in Champagne, one expert told me that the Magnum (1.5L) was the best size bottle for conservation of the wine. Why is that?
In a magnum or even better in a larger container, wine blooms more freely, matures more easily. Its own volume enables it to own a greater share of aromatic components that were previously in the barrel or tank. But above all it will air more efficiently when serving since the surface of wine in contact with air will be significantly greater than it would be in the bottle. It is as efficient as pouring the content in a pitcher, without having any additional dishes to wash!
A large format will also keep the wine better and longer. Two reasons for this greater longevity magnums and other major formats. The first is that the larger containers have a higher thermal inertia when the temperature varies, so they take longer to cool or warm up. Wine is therefore subject to less thermal "turbulence". The second reason is that the proportion of air trapped between the cork and the wine is less in a large container in a bottle. The micro wine oxidation will be even slower than bottled.
