The following is an excerpt from an article on Bordeaux in the Snooth wine website
What exactly is En Primeur?
The simplest answer is wine futures. Each spring the Grand Cru Classe chateaux produce barrel samples from the previous year’s vintage, in this case 2015. These wines are not ready for market, in fact they won’t be released for 1-3 years. Members of the international wine trade descend upon Bordeaux for a week to taste these samples. Upon conclusion a so called “buzz” is created. Is it a great vintage? Poor vintage? Average? Best in decades? How was the overall en primeur of the vintage received? At this point prices are determined and wine brokers, known as négociants, begin to sell the “futures.” This process is good for the chateaux because their risk of a poor vintage is spread out by the négociant; meaning a poor vintage still equals profit. Furthermore, the chateaux receives cash before the vintage is ready so they do not have to wait for barrel and bottle aging to profit from each vintage. The négociant is in a tough situation because in order to maintain their allocation they must buy their fully allotted amount in good vintages and in bad. If they chose to not take their full allocation in a poor vintage year they risk losing the allocation in a potentially good vintage year.
How does Bordeaux’s En Primeur affect wine consumers?
Interestingly, the average American wine consumer seemingly knows little or nothing about En Primeur. If you are an oenophile who seeks to stock your wine cellar with some of the highest quality Bordeaux from the best vintages with little concern of price, chances are you are well aware of En Primeur and have a wine merchant to supply you Bordeaux futures. If you are a wine consumer who enjoys Bordeaux and is constantly seeking a bargain En Primeurs has little to no effect on your wine buying and consumption. There used to be a discount for buying En Primeurs but it has diminished over the years. European wine press and consumers, especially in the UK, seem to be more attentive to En Primeur than their US counterparts.