Whisky writer John Lamond delves into the issue of corks.
I must confess from the start: I am a dinosaur. A hopeless traditionalist. I like corks. I know all about the problem of whiskies – and wines – ruined, utterly destroyed by cork taint. I know that the theory is that a screwcap or synthetic cork should eliminate the problem, but I like to see a bottle closed by a natural cork. It is a natural thing.Cork is the outer bark of the evergreen cork oak (Quercus suber).This species covers 2.7 million hectares of Spain, southern France, Italy, The Mahgreb of Morocco, Tunisia and Algeria and, especially, Portugal, which accounts for 51 per cent of world cork production.In some Portuguese villages, such as Luzianes-Gare, some 100 miles south-west of Lisbon, up to 80 per cent of the inhabitants depend upon cork for their economic survival. The cork forests support more than just the people directly involved in the cork industry.In the small town of Odemira (just to the west of Luzianes), Alcinda Catarina Jacinto has been making cheese all her life. She buys her milk from local farmers – milk from sheep and goats that graze beneath the cork oaks; her neighbours harvest honey from beehives in the cork forests; acorns from the cork oaks are used for animal feed; and fruit and berries go into other local produce.The forests are also home to a rich variety of wildlife, including endangered species, such as the world’s rarest (and Europe’s only) big cat, the Iberian lynx, the Iberian imperial eagle in Spain and Portugal and the Barbary deer in Tunisia. In addition, Europe’s entire crane population overwinters among the Iberian peninsula’s cork oak trees. The Iberian lynx is now rated as “critically endangered’ – the only big cat species to be so listed. It is the world’s most endangered cat species and is so close to extinction that it is now estimated that fewer than 100 remain.There are conflicting opinions about what should be done to save the lynx, but all experts are agreed that the survival of its habitat among the cork oaks is central to the animal’s survival. The World Wildlife Fund has highlighted the fact that the lynx’s survival is dependent upon our continued use of natural corks. As a crop, cork is a completely sustainable resource – it is both renewable and biodegradable. Cork harvesting is an environmentally friendly process during which not a single tree is cut down. Once harvested, the bark renews itself during the following nine years, ready for its next harvest. A tree must be more than 25 years old before it can be first harvested and it is not until its third harvest that the bark can be used for the production of whisky (or wine) corks. Bark from the first two harvests is used for other products.Each cork oak tree produces an average of 16 harvests during its 150-200 year lifespan.The oldest cork oak tree in existence is known as the Whistler tree – it is now more than 225 years old. When last harvested, during the year 2000, it took a team of five men four hours to harvest 650 kilos of cork which produced around 55,000 bottle corks.Cork consists of a tight web of up to 40 million cells per cubic centimetre. The structure and make-up of these cells is responsible for cork’s suitability for the uses to which it is put; it is light, resistant to wear, stable in size and, very importantly, elastic.The great flexibility of the cell membranes gives compressibility and flexibility.Cork for bottle stoppers account for 70 per cent of the total value of the cork market. It is a material which is ideally suited as a bottle stopper: it is natural, innocuous, chemically inert and does not degenerate, although it does eventually biodegrade. It is also recyclable.The downside is that there is a bacteria known as 2-4-6 trichloroanisole, affectionately(?) known as TCA, which is endemic in cork forests. This bacteria is also sometimes found in cork stoppers, resulting in the contents of the bottle sealed by a cork stopper being spoilt by cork taint.Cork taint destroys the richness in the liquid, be it whisky, wine, olive oil, or whatever. It leaves a distinctive aroma of wet cardboard, rising damp or dry rot and flattens out the flavour of the liquid. TCA is frequently found in water systems in institutional buildings – and costs the earth to eradicate! I lecture in a college in Glasgow which has spent enormous sums cleaning out its water system – to no avail.I advise my students to nose and taste the water so that they will learn what TCA smells like.Whisky sales started by the cask. Barrels were situated on the end of the bar. From here the barman served the drams. In the 18th century, the driven cork came into frequent use. By the early 19th century, they were commonplace. Whisky drinkers needed a corkscrew among their repertoire and had to adopt the Scottish West Highland habit of throwing the cork in the fire and drinking the whisky until the bottle was finished. That is until the advent of what we now refer to as a bar top cork – one with either a wooden, or commonly nowadays, a plastic top, intended for frequent removal and replacement.In the 1920s, innovation in whisky bottle closures was a levered, flip-top metal cap which could be easily replaced. This was superceded by ROPPs (roll on, pilfer-proof caps), stelcaps (ROPPs with a collar which extends down the bottle’s neck) and various non-refillable fitments, such as the widely available Guala.Plastic, or synthetic, corks gradually became acceptable, especially in wines, in the early 1990s, although many people within the drinks industry worldwide had their reservations about them from the outset. Within the past couple of years, synthetics have been attacked by some critics for inflexibility, taint from the plastics, oxidisation and the development of offflavours over time – sulphur aromas can develop if there is a total absence of oxygen. Natural cork allows minute amounts of oxygen transfer through the cork. This is necessary for even maturation in the bottle.John Glaser of Compass Box Whisky has been innovative in that he embraced synthetics early on, as being a stopper which would not sour the contents of his superlative bottlings. But, he has since recognised the problems of removal and replacement of synthetic stoppers and gone back to natural cork. Synthetics do not have the elasticity of natural cork and consequently are either too small and permit leakage or too large and impossible to get back into the bottleneck.It has taken the cork industry more than 300 years to properly address the taint issue, but during the past 15 years, it has been making great efforts to eradicate the problem. My own experiences of wine in the late 80s and early 90s were that between five and seven per cent of bottles were affected to some degree or other (some writers were suggesting, fifteen years ago, that the figure was around 12 per cent) – I now experience less than 2 per cent.My experience of plastic corks is that around the same percentage of bottles sealed with a synthetic cork is oxidised.Whisky is completely different issue. It seems that, as whisky spends a relatively short period of time in the bottle, the effect of TCA is diminished.Reports from whisky companies are that complaints about TCA affected bottles were always very low in number and currently on the decrease. Speaking with some of the larger companies, their reported incidence is as low as “one bottle in the past eighteen months.” Ewen Mackintosh of Gordon & MacPhail, however, reports a slightly more realistic figure; from their own bottle openings, they are experiencing less than half a per cent.Amorim says that there seems to be a correlation between cork grade quality and TCA – the better the grade, the lower the incidence of TCA, and that, by using the company’s ROSA system, where steam and water under pressure force out volatile compounds such as TCA, the level of releasable TCA found in a whisky is drastically reduced – to anything up to 70 to 80 per cent of its original value.These developments are, obviously good news for the consumer, in that more bottles are being delivered to them in the condition that the producers intended. The problem is that winemakers have adopted the new technology as a result of the cork producers’ failure to timeously address the problem. In excess of 80 per cent of the wines – both red and white from New Zealand are now sealed by screwcap closures. And yet, from last year, the International Wine Challenge is now categorising the faulty bottles it opens.In 2006, the organisers opened 54,666 bottles, of which 2.8 per cent were affected by some sort of cork fault, whereas 2.2 per cent were affected by some sort of fault caused by screwcaps! The much-trumpeted saviour closure, it seems, is every bit as guilty of causing faults as is the vilified natural cork.If the rejection rate of natural cork closures by producers continues, the World Wildlife Fund estimates that, by 2015, the world will need only 19,542 tonnes of cork. That is down from 300,766 tonnes in 2003. A reduction of 93.5 per cent.The related job losses will be in a similar ratio, down from 66,876 in 2003 to 3,346 in 2015.The impact on the local environment would mean a continued loss of habitat to the various endangered species, as it is human control and management of the Spanish dehesa and Portugal’s montado which have endowed these areas with such biodiversity. Without it, there would be more fires, resulting in deforestation.Without the trees, there would be no thriving fauna beneath the trees fed by humus from material falling from the trees.Without the shelter of the oaks, there would be less water retention in the soil.Without this undergrowth, there would be soil erosion and desertification of large expanses of these areas.Screwcaps utilise natural resources; although recyclable, they rarely are and do not biodegrade; their inclusion in landfill merely serves to raise toxins in the soil and our watercourses.With the World Wildlife Fund highlighting the environmental importance of the humble cork, it is surely worth the risk of the odd faulty bottle to help preserve the environment?Drink cork-stoppered bottles and help save the planet!
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