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It’s all in the barrel mix

It is claimed that a barrel can make or break a wine, depending on where it's from or how much it is toasted. ADAM LECHMERE finds out why producers are so fussy about their oak.

A cooper’s life, you feel, must be a happy one. In winter the oak-fired braziers used for toasting provide a centre of warmth in the draughty industrial barns at the heart of a cooperage. In summer, oak dust floats in the sun and the air is filled with the tang of cut wood. In all seasons there’s the ever-present racket of hammering as iron hoops are cold-chiselled onto staves, barrel heads are battened on and pegs sunk.

Barrel making is a labour- intensive business. From cut plank to finished 60-gallon barrel takes a dozen or more processes, all requiring, at some stage, ancient skills and tools that have changed little in the last few millennia. While much is automated – any modern cooperage has band saws, mechanical lathes, sanding machines and tension winches – the cooper still uses hammer and notched chisel to fit the hoops (see photo, right), and sharp crescent adzes (axe) to trim the chamfered (angled) upper barrel rim.

It’s an ancient art. In the 13th century BC the Celts shaped wood for boats, and by 350 BC they had worked out how to make strong, watertight containers (tonneaux) by forcing wooden staves into iron hoops. Since then barrels have been used to transport anything from salted fish and mustard to books and spices. Caesar allegedly used them to drop boiling oil on mutinous colonials. Above all, they proved invaluable for wine.

The first person really to study the influence of wood on wine was Louis Pasteur in 1860, who discovered that vinegar-producing bacteria flourished on contact with air, and that a tiny bit of oxygen improved wine in the barrel. Coopers still say barrel making is an art, but there’s a lot of science involved too. While barrels are toasted over braziers fuelled with oak off-cuts and briquettes of recycled oak sawdust, the precise heat during toasting is likely to be computer-monitored. The action of oak on wine and the reasons for it have been recorded in detail –

Paul Pontallier, Château Margaux’s director, did his PhD on the subject. feeling toasty Toasting – scorching the inside of the barrel – is the most important process. The toast forms a barrier between the wine and the natural tannins in the wood. The less a barrel is toasted, the oakier the flavour, while a heavier toast imparts a more spicy flavour. Pinot Noir and Chardonnay suit more toast, while Cabernet Sauvignon responds better to less. Oak, coopers say, is as sensitive to terroir as vines.


Quercus sessiliflora and quercus robur are the two main European varieties, covering 14 million hectares of France – a quarter of the country. They grow in the great forests of central France: in Vosges, Jura, Burgundy, Argonne and Limousin. American oak is almost as widely used as French, although the strong flavours it imparts are often looked down on by those who favour the more reserved, ascetic European style. Again, terroir matters: Kentucky oak imparts mellower flavours than Oregon for example. Many big American producers, such as Ridge, ZD and Beaulieu, use different percentages of American oak. Winemakers and coopers are divided as to the importance of terroir. Jean-Marc Didier of Quintessance Bordeaux maintains quality of wood is all and origin makes little difference. ‘Fineness is more important than forest.’

Pontallier, who reckons his studies and his work at Margaux (one of the handful of Bordeaux properties with its own cooperage) ‘has led to more doubting than certitude’, goes along with that. ‘Going into which oak from which forest is a nonsense – that’s going too deep for our knowledge. I never ask for a specific forest. I defy anyone to be sure about that.’ A cooper’s American customers tend to be more demanding. ‘They are very keen,’ says Jean-Jacques Nadalié of major Bordeaux coopers Nadalié. ‘They want medium toast, medium plus, toasted heads. They specify exactly which forest they want the wood to come from. A French winemaker will say: “It’s your job. Do what’s best for us.”’

But the best wood is limited. Tronçais, prized for its tight grain, can be difficult to get. Mark Beringer of Beaulieu has different relationships with vendors. ‘Some give me what I want, others allocate.’ From Nadalié he can buy ‘containers of Tronçais practically at will’, but from Taransaud he has to take a mix, which may contain Tronçais and may not. If effects of forest and wood type are an imponderable, how to treat the wood is another. How long should the cut planks be dried for? Is natural air-drying better than kiln drying – and is the latter what gives American oak its spice? No one really knows, although you’ll always find a cooper to defend his or her practice. So despite the science and experiments, barrels are still a bit of an unknown. After all, they’ve been making wine in Bordeaux for centuries, but only in the last 20 years have they really started thinking about the effect of the barrel.

Château Figeac director Eric d’Aramon, for example, is about to embark on some serious monitoring with a computerised traceability programme. ‘We will know the type of wood, the origin of the wood, and the percentage of wine that goes into which barrel from which cooper.’ the more the merrier The best thing is to have a choice of barrels. Any major producer is supplied by five to eight coopers – and any great wine has had contact with that many barrels. The cooper is a key member of the winemaking team. Tastings take place throughout the barrel life of the wine, with constant reference to toasting levels. Christine Nadalié, of Bordeaux coopers Nadalié, remembers one blind tasting. ‘I tasted seven different coopers, and the last one I marked down – it was not toasty enough for me. It turned out that wine was from my barrels.’ When something doesn’t work, the cooper experiments – but not much. The two most important things, according to Julien Segura of Bordeaux cooper, Boutes, are the choice of wood and the choice of toast. He adds that châteaux are very keen on constancy. ‘They want everything to be as regular as possible,’ he says. At Quintessance Bordeaux only 30–40 barrels a day are produced, and Jean-Marc Didier forges close relationships with clients. ‘A producer will say, “this barrel gave me what I wanted so I want the same again”.’

While there are fewer cooperages now than before, they are getting bigger. With more automation and more efficiency a company like Boutes produces 150 barrels a day, at t460 each, and the business is consolidating and expanding. Boutes keeps its cutting operation actually in Allier, close to the forests. Séguin Moreau has a major operation in Napa, as does Nadalié, which also operates in Chile. The US produces 800,000 barrels a year, France around 200,000 (of which half are exported – mostly to the US). The Spanish and Portuguese industries never declined, due to demand for sherry and port barrels. Barrel making in its modern form is a young business in a state of flux. Visit any cooperage and you are struck by the enthusiasm of everyone involved. There is the satisfaction of seeing an ancient profession revived, making the best use of sophisticated technology alongside age-old skills. And just as vintners are never 100% sure how a great wine is achieved, nor if they could do it again, the cooper knows he is working with a living substance. As Jean-Jacques Nadalié puts it: ‘They are never the same. If you produce 50, not one barrel will be exactly like another.’

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