How oak barrels influence the taste of wine

Those who know me know that my guilty pleasure is a glass of good wine, but also to learn as much as I can about that wine, about wines in general. I thought you might also be interested in learning a bit about how oak barrels influence the taste of wine, what the difference is between wines that have come into contact with oak and those that have not, what some of the information written on the label means. Maybe this will make it easier for you to choose the wine you like or to give as a gift.

The barrel was originally used for storage and transport

Since ancient times, people have been looking for ways to transport and store wine to make it last as long as possible. The Greeks kept it in clay amphorae and added olive oil on top to keep the air out. But the Romans discovered that wine was much better transported in oak barrels, and that it lasted longer. So, as early as the 3rd century, they replaced amphorae with oak barrels.

The barrel has been the only container for making, transporting and storing wine for a long time. But the modern era saw its gradual replacement by glass and then stainless steel and fibreglass. However, it could not be totally replaced because, while in the past it was chosen on the basis of experience, gradually science demonstrated the influence of the barrel and the aromas released by the oak in the formation of quality wines.

Oak - the spice cabinet

About oak is said to be the spice cabinet of the wine makers. It adds a range of flavours and aromas to wines, increasing their value, making them more sophisticated. The main reasons it is chosen are:

• It is a natural antiseptic. Wine that ferments or is matured in oak barrels needs less sulphur dioxide;
• Helps to clarify and stabilise the wine. This eliminates the use of fining additives;
• In the case of red wine, it "tames" the tannins, stabilises the colour and helps in the ageing process;
• It adds certain flavours, making the taste more complex and sophisticated.

European oak versus American oak

Wine kept in oak barrels is not hermetically sealed as it is in a glass or stainless steel container. Through the pores of the wood it has contact with the air so the size of these pores is very important. Wine barrels are made from two types of oak, European oak and American oak. European oak has a finer texture and smaller pores, while American oak is coarser and has larger and more pores. The largest suppliers of European oak are France, Croatia and Hungary.

If the wine is in a European oak barrel, less air enters, fermentation is slower, and the resulting wines have a finer, more subtle taste. With American oak, more air enters, fermentation takes place more quickly and the wine tastes rougher, harsher, more manly.

The size of the barrels is also important because of the amount of air the wine comes into contact with. In small barrels the wine has more contact with air than in large barrels. Wines such as Amarone or Brunelo di Montalcino, Italian red wines that are kept in very large casks (botte) with a capacity of 1000 l to 15000 l have a strong and manly taste.

Water and alcohol evaporate through the pores. It is estimated that 10% is lost from a typical 225 l barrel in a year. Experts call this amount side of angels. Losing this quantity intensifies the concentration of flavours. In the case of red wines, which age over a longer period, new wine is added every year so that its taste becomes very intense and needs hours after opening to bring out all the flavours. This is why it is recommended to put it in special glass decanters during this period.

Controlled burning of the barrel inside releases distinctive flavours

I was saying that oak adds a number of flavours to wine. They can be vanilla, coconut, cinnamon, clove, nutmeg, cedar, chocolate, coffee, fig, burnt wood, smoke. All these flavours come only from wood and to enhance them the barrel is superficially burned inside.

By burning lignin decomposes releasing all these flavours. Depending on the wine producer's requirements, the wood may be burned more or less.

Cost-saving options

The elaborate barrel-making technology, the slow growth of the oak (min. 80 years for harvesting), the fact that only two barrels can be made from the trunk of an oak tree, and the fact that the process takes up to 36 months (washing is done to remove unwanted tannins) make the barrels very expensive, which is reflected in the price of the wines. The barrels can only be reused for three years, after which they lose all their natural flavours, taking on those of the wine and need to be replaced.

That's why some producers choose to flavour their wine by using pieces of oak mixed into the wine during fermentation or ageing. The method is approved almost everywhere in the world. The label on these wines does not say they have been aged in barrels - barricadedhere oak influence- taste influenced by oak or oak maturation- oak aging.

Oenological tannins extracted from wood are also sometimes used and approved in most countries. It can be identified that such tannins have been used when the wine tastes the same regardless of the year of production. Wine is made from grapes and the grapes are influenced by sun, rain, cold, terroir (the soil in the area). It is not possible for them to taste the same every year. Sometimes they are more watery and less sweet, sometimes sweeter and drier. This is reflected in the wine.

The taste of oak in wine is not unanimously appreciated

Not everyone appreciates the influence of oak in the taste of wine. While there are tannins in red wines anyway, and the influence of oak is not so important, for white wines it is very noticeable. Especially for wines kept in American oak barrels.

Experts say the difference is best seen in Chardonnay. While young wine fermented and kept in stainless steel vessels has a light, fruity taste, wine kept in oak barrels is harsher, creamier and has aromas of vanilla and butter. The colour is also different. The one kept in stainless steel is pale yellow, while the one kept in oak barrels is dark yellow.

Not only oak barrels are used for wine. Over time it has been found that both acacia and chestnut have a positive influence on the taste of wine. However, oak remains by far the most widely used wood for obtaining barrels and the one that gives wine its greatest and most sophisticated range of flavours.

I hope you find the above information useful. As usual, additions are welcome. And if you have any questions or queries, please leave them in the space below. I'm sure I'll reply.