Barrels

Oak barrels are an important part of winemaking.

They are porous and allow for a slow, controlled introduction of oxygen into the wine through a process called micro-oxygenation. This helps soften the wine's tannins, making them smoother and less astringent. Oak tannins can interact with the wine’s tannins,  contributing to the overall structure and stability of the wine.

Oak barrels also impart flavours to the wine, be they red or white. Typically these flavours are brown baking spices such as cinnamon clove and nutmeg. Other flavours include vanilla, chocolate, cocoa, coffee, and smoke.

Barrels are made by coopers. Coopers assemble the staves, the pieces of wood that make the barrel, and attach the ends called heads.

Historically barrels were held together by wooden rope, but now the hoops are made of steel or aluminium.

The inside of the barrel is burned, or ‘toasted'. The more heavily toasted the barrel, the more pronounced the flavour of vanilla, baking spices, coffee, or chocolate, etc. Lightly toasted barrels minimize such flavours and aromas.

The traditional barrel size is 225 litres, equivalent to about 25 12 bottle cases of wine. These barrels are also know as barriques.

The next size up is 228 lites, a size commonly found in Burgundy. Another somewhat familiar size is 300 litres and is commonly used in Bordeaux.

A 500 litre barrel is known as a puncheon, while 1000 litres and larger are called foudres.

Over in Portugal a 550-650 litre barrel is called a port pipe.

Smaller barrels have a higher wine to wood ratio, leading to more interaction between the wine and the wood, which results in more pronounced flavours and faster aging.

Larger barrels have less surface area contact with the wine, leading to a slower aging process and reduced evaporation, or what is referred to as the "angel's share”.

As wine rests in barrels, someone is there topping them up every so often to reduce the wine’s exposure to oxygen. Too much oxygen is detrimental and lead to loss of fresh fruit aromas and too much browning, but by and large, barrels offer just the right amount over time.

Barrels will offer up the most aromas, flavour and texture when they are brand new, and slowly decrease these offerings with a few passages of wine. After 3 or 4, there is very little a barrel can offer other than micro-oxygenation. That is why you might hear a winemaker say 50% brand new French oak while the remainder could be old oak.

Oak barrels are a huge expense with a 225 litre barrel costing about $1500 for an American oak barrel and usually twice that for French.

Due to this expense some winemakers employ more economical alternatives such as adding wood chips or staves to the wine while it rests in a stainless steel tank.

Like so many processes that stand the test of time, what was once considered old is new again: the ancient technique of using clay amphoras is becoming fashionable aging. You can find them in most cellars these days as they help the wine retain the primary fruit aromas while allowing for the benefit of micro-oxygenation without the tannins, aromas and flavours that oak provides.

Whichever method a winemaker chooses will confer a different outcome. It is worth asking which oak, and for how long, a wine has spent in barrel. Over time and with enough practice, you might even be able to detect which forest the oak was grown in!