Wine vats dating back 6000 years have been discovered in Armenia. They are more than 1400 years older than the Pyramids of Gisa and preceded the reign of Cleopatra in Egypt by nearly 4000 years. Wooden wine barrels have existed for at least 2000 years possibly far longer. So as you can imagine they have had a long history to get to the modern-day version, far too long for this blog to go into fine detail. Although it is not known who exactly invented the barrel, as we know it today, we do know that the Romans adopted and spread it around their empire sometime around 350BC. And these sturdy vessels were widely adopted. Today wine vats are used before the wine is racked in barrels. They are where the grapes are stored to collect the juice from which the wine is produced without altering its taste or chemical composition. Wine barrels are then used to age wine, to enhance flavour, maturity and longevity after bottling. Originally the reason for using barrels did not have anything to do with the taste. They were merely for storage as they were far easier to handle and less fragile than the ceramic pots or skins used at the time. But over time we came to realize the qualities they can add to our wines.
Oak is considered the best wood for wine barrels and as such is sought after as being the predominant wood. The types of oak that are most commonly used are French common oak, white oak, or American white oak. A lot of the flavour the wine gets from the barrel is from the raw wood itself. For a long time now winemakers have known that “toasting” the inside of the barrel by exposing it to raw flames, can enhance the flavour. There are different grades of “toasting” ranging from light, around 25 minutes, to heavy in which the barrel can be exposed to the flame for up to an hour.
The heavier “toasting”, imparts a stronger and more varied flavour:
Light Toasting - Vanilla, caramel, clove and cinnamon
Medium Toasting - Vanilla, honey, caramel, coffee, toast
Heavy Toasting - Vanilla, smoke, butterscotch, toffee, molasses
The way the oak interacts with the wine also varies depending on the grape variety. Several chemical processes occur when the wine interacts with the barrel, some of these chemicals being tannin, sugar and vanilla aromas. This results in a fuller-bodied, complex and concentrated palate. It also affects the colour, intensifying it. Two things happen when an oak barrel is used, firstly there is constant gradual evaporation, and the wood absorbs the wine. This means the barrel constantly needs to be replenished with the same wine, a labour-intensive practice. Secondly, it provides an environment for metabolic reactions to occur which add to the wines flavour.
Oak barrels can be used for both white and red wines, however, certain types of white wine grapes are not suitable for barrel ageing, the reason being that the oakiness of the barrel may overwhelm the grape flavour. Only fruity and intense wines are aged in oak barrels.
There are also new and old oak barrels. Simply put the newer the barrel the more concentrated the effect the wood will have on the wine and with each vintage going through the barrel it will lose the flavour giving effects. New barrels are an ongoing and costly expense facing winemakers. As such some wine producers will age a portion of their wine in new oak barrels to provide some complexity and flavour, then blend it back into the rest of their wines and save on barrel costs without diminishing the end-users, you and I, taste experience. As older oak barrels still provide some really amazing nuanced flavours.
The size of the barrel used also matters as the larger the barrel the less the oxygen and oak lactones that are imparted into the wine, but that is for another blog.Deciding on the size, wood type and grade of toasting to use all form parts of the winemaker's immense skill set and is all about bringing us the best wines for us to enjoy.