Oak Barrels in Winemaking
One of the places I love most when wandering around a winery is the barrel cellar. Sometimes the rooms are very grand and resemble cathedrals with their arches, murals, emblems and atmospheric lighting. Others are sometimes rather dank, featureless, concrete buildings that resemble bunkers. Nevertheless, the sight of myriads of curvaceous barrels stacked on top of each other, together with the wondrous smell, make this a great place to linger.
The wooden barrel has been used in winemaking since the 3rd Century when it replaced the amphora as the vessel of choice. Wood has a natural affinity for wine. Not any old wood though – usually it is European or American white oak that offers the perfect match with wine.
So what is the exact function of a wine barrel?
The wood is porous so it allows a slow micro-oxygenation of the wine which helps to impart smoothness, roundness and suppleness. It also gives a flavour to the wine; the newer the barrels the more powerful the flavour. Complex compounds such as vanillin are absorbed from the wood as well as tannins. These depend on where the wood comes from, how the staves were cut and dried and the degree of ‘toasting’ or charring of the inside of the barrel.
Wooden barrels also help clarify the wine (making it clear) as well as stabilising (fixing the colour). Most red wines are now matured in oak barrels, many are also fermented in oak too, which imparts a richer mouthfeel and texture to the wine. A good number of white wines are also fermented and matured in barrel (especially Burgundy wines) with bâtonnage or stirring of the solid matter (or lees) being done regularly to increase the richness and texture.
Some evaporation takes place – which is commonly referred to as the ‘Angels’ share’. It means that each week, topping up must take place to ensure that the barrels are kept full thus reducing the likelihood of oxidation.
Barrels come in many different sizes. The Bordeaux barrique is 225 litres. The Burgundy piece is 228 litres. The hogshead is usually 250 litres. The sherry butt is 500 litres and the Port pipe 650 litres. The foudre is a large wooden vat for fermenting or maturing wine and is usually between 20 and 120 hectolitres in size (100 litres is a hectolitre). You tend to see these frequently in the Rhône Valley and Alsace.
French oak is one of the most prized of all and is sought after throughout the wine world. After World War II, the French carried out some two million hectares of reforestation and it continues to be managed very carefully to this day. In fact a quarter of France is made up of forest and a third of this is oak. It is therefore an abundant resource. The oak trees are usually between 80 years and 300 years old and come from five key areas. You have probably passed through them on your travels throughout France. They are hard to miss! These regions are:
- The Central region (to the east of Tours in the Loire Valley)
- Nevers (to the west of Burgundy)
- Tronçais & Allier (to the northwest of Lyon)
- Limousin (south of Limoges)
- Vosges (in Alsace)
Each year, some 200,000 barrels are made by the Tonnelleries of France. Many of them are exported around the world.
Many of our vineyards have impressive barrel cellars. When you next visit one, go and stroke a barrel. They are marvellous things, beautifully crafted by a Tonnellerie or cooper and have a lovely texture and smell. They are expensive, usually costing €600-700 or more. They are normally used for up to three vintages and then they are used in the sherry or whisky industry – or for garden ornaments! Because they are so expensive, oak chips are often used – certainly cheaper, but not so fine. Staves can also be used which act as oak planks inside a vat. They are better than chips, but not as good as barrels.
Bordeaux is a great place to see impressive barrel cellars. Château Mongravey in Margaux has a lovely one. Our Margaux Cuvée 3D is a blend of Cabernet Sauvignon and Merlot and is matured in eight different barrel types that impart different flavours to the wine. It’s a bit like seasoning in cooking. Our wine usually spends up to 18 months in barrel. If you detect vanilla, spices, toast, mocha, cream and butter in your wines, then it is likely that the barrel has had an influence on the taste. The key challenge for every self-respecting vigneron is to ensure there is proper balance between the oak and the fruit. Tasting Régis Bernaleau’s Margaux you will see this maxim personified in his deliciously elegant wines.
If you would like to visit a famous Tonnellerie and see for yourself just how barrels are made – it is an incredibly artisanal craft – you could always join us on our annual pilgrimage to Burgundy in June where a trip to the world-famous Tonnellerie François Frères is on the agenda. It is a remarkable spectacle.