A precious commodity
- Saturday 1 December 2001
French oak has always been synonomous with quality wine. ALAN SPENCER finds out what makes it so desirable
Bacchus has always been depicted sitting astride a barrel. From ancient times wine and wood have been closely associated, yet the idea that premium wines benefit from wood ageing, especially new wood, is in fact a very recent concept.
Indeed, research shows that the taste of oak is not a very important factor. Pascal Collote of Tonnellerie Saury in France goes so far as to say: 'A wine should never have the taste of wood.' The purpose of oak ageing, he points out, is to compress the wine, to give it fat, length and structure. And not every wine will benefit from barrel ageing. 'What interests us above all is porosity,' he says. 'The taste of the wood is subordinate.' A technical pamphlet published by the CIVB warns: 'Injudicious oak ageing may impart excessive wood odours or make the wine too dry, depreciating its intrinsic qualities'.The essential action is through oxygen penetrating the wood's pores and bung-hole to create moderate, continuous and slow aeration. The small volume (225–300 litres) provides the ideal surface, promoting sedimentation of the lees.
Half the cost of a barrel is the raw material and, especially since the great storm of 1999, quality French oak for cooperage, called merrain, has become scarce, pushing up prices. Today, a French oak barrel will cost between FF2,800 (£271) and FF4,000 (£386) depending on quality, and the average price per bottle of ageing in wood, using one third new barrels, has been calculated at FF12 (£1.15).
Barrelmaking no doubt evolved from boat building – an enterprising carpenter thinking up the principle of using watertight planks to keep liquid in not out. The basic principle is unchanged. Although industrially made barrels from American oak can be mass-produced, French oak barrels for premium wines are custom-made and each is slightly different. The staves (on average 30 to a barrel), machined to the curved shape and gouged on the inner side, are set upright in a 'rose' held by a hoop, and placed over a fire-pan.
Swabbed with a wet rag to help the heat penetrate, they are gradually winched together using a cable to form the bilge (from the French bouge), with the entire mass resting on a few square millimetres. For premium French barrels, the end-boards are still jointed with reeds, assembled with gudgeon pins and sealed into a groove with flour-paste.
A new operation called toasting has been introduced, which helps the wood liberate its specific flavours. Medium burning (10–15 mins) yields odours of vanillin and toast. Heavy toast (15+ mins) releases smoky and spicy flavours, and each cooperage has its own techniques. Many top coopers, like Séguin-Moreau, manufacture their own staves. Tonnellerie Nadalié in the Médoc was the first (1964) to set up a stave-mill in the Allier and now has 14 different woodyards and four cooperages in France. As well as burning barrels on the inside, Tonnellerie Radoux may toast the head and bottom boards by placing them on heated bricks in a revolving kiln. For the last five years, the Saury cooperage in Brive has developed a special technique for barrels destined to vinify and age white wine by plunging them into hot water.
Today, wines labelled 'élevé en fûts de chêne' are considered to be superior, though the term usually signifies a few months in white oak made or imported from America. There has been a marked increase in the use of American oak (+20%) mainly due to the emergence of new-style, powerfully built wines with sufficient structure to enable them to withstand short ageing (of between three and six months). Prices for these wines will be lower because white oak can be sawn, providing more economical use of the timber.
French oak has a fine grain and cannot be sawn without breaking the veins. The log, cut to length, is split into quarters from which two staves can be made. For that reason, waste may be as high as 80%. French oak barrels cost roughly twice as much as those made of American oak, but the fine grain is suited to ageing premium wines. Splitting along the grain means penetration is slower, and fine French wines are aged for 15 to 18 months.
In addition to the cost of raw material, staves have to be weathered. When a tree is felled, it contains roughly 80% humidity which needs to be reduced to 15–18%. Christian Liagre at Tonnellerie Radoux estimates that he has FF100 million-worth (nearly £10 million) of French, American and European oak stacked for weathering. Although Séguin-Moreau, Radoux, Saury, Nadalié, and others produce some of the best fine-wine barrels in the world, the winemaker will always use a mix purchased from different cooperages. Just as wines are blended to produce the final product, so different qualities of barrel produce different qualities of wine. Also barrels are made individually so that quality may not be the same from year to year and one objective is consistency.'We have now implemented a policy of integrated manufacture which applies from the moment we pinpoint a tree in the forest,' says Jean Bourjade, president of Séguin-Moreau. 'We have our own buyers who select and buy standing timber, and our own merranderie for making the barrels.'
Henri Barthe of Tonnellerie Boutes, in Narbonne, explains the importance of selection: 'I supervise the purchase each autumn of standing timber, weathered in our merranderie and woodyard beside the Allier forest. The quality of the wood, and therefore of the staves, is the vital first step in the making of our Grande Réserve Bordeaux château barrels.'
According to Jean-Jacques Nadalié, president of Tonnellerie Nadalié, it was the first (1980) to set up a cooperage in the US, in Calistoga in the Napa Valley. 'We were pioneers – the first to use French techniques to make barrels of American oak.' Today, some 70% of French barrels are made for export – the most important markets being the US and Australasia, but supplies of French oak over the long term are limited. The average age of tall, straight oaks (Haute Futaie) for felling is about 180 years. And so although 25% of France is covered with forest, French coopers are understandably looking at new sources of supply and are experimenting with stave-timber from Russia (Caucasian oak) and eastern Europe. But buying standing timber can be complicated because, from a given lot, only a proportion of the trees will be suitable for barrelmaking. The others must be re-sold.For that reason, as policy, certain quality cooperages prefer to leave the purchase of timber to the timber merchants and the preparation of staves to the merrandier (stave-maker). The final test is tasting, and wines from different French barrels are regularly tasted in the cellar. Only between three and five percent of wines produced today are oak aged. Since the tendency is to drink less but better quality wine, even if only one percent more wines are oak-aged, coopers have a very busy time ahead.