Jackson Estate in New Zealand’s Marlborough region is celebrating 30 years of production. For publication in the week starting 26 March 2018.

In 2001 four New Zealand wine companies initiated a bold experiment. Forrest Wines, Lawson’s Dry Hills, John Belsham and Jackson Estate pioneered the use of screw-caps instead of cork. All are based in the Marlborough region at the top of the south island.

Since then what was pioneering has become accepted. More than 90 per cent of wines in New Zealand are sealed with a screw-cap, and in neighbouring Australia the percentage is even higher.

A key question always arises when people debate the benefits of cork versus screw-cap. Which is better for long-term cellaring? A dinner in London earlier this month to celebrate Jackson Estate’s 30th anniversary presented a chance to compare wines from that 2001 vintage sealed with both cork and screw-cap.

Screw-caps for wine bottles have been around since the 1950s but they were mostly used for sealing cheap wine. A screw-cap seals the bottle and prevents oxygen from entering. Advocates maintain that wines remain crisp and well-preserved. Detractors say screw-caps do not allow wines to evolve, because the minute amount of oxygen that a cork permits helps a wine to develop.

That is an old argument. Modern screw-caps allow calculated levels of oxygen to enter the bottle over time. They are about a third of the price of a cork.

Winemakers started considering screw-caps about 15 to 20 years ago because of the high number of wines tainted by defective corks. Perhaps one bottle in 30 was affected. The problem also led to development of artificial stoppers made from things like plastic and glass, and composite corks created by crushing cork bark into tiny granules and then constructing a stopper by melding the granules with beeswax and vegetable oils. Probably the best known of these is the Diam cork. See the column of 20 March 2017 for more information.

The main source of cork taint is a chemical called 2,4,6-trichloroanisole, usually abbreviated as TCA. It occurs when a fungus that lives in natural cork bark comes in contact with chlorine, typically during the bleaching process or when rainwater soaks into stacks of bark left to dry in the sun. Even at very low concentrations TCA can strip a wine of its character. The wine fails to exhibit the kinds of flavour or aroma usually associated with it.

Some people dislike screw-caps because they change the ritual of uncorking. But they are easier to open and we do not find cork fragments floating in the wine.

Jeff Hart, managing director at Jackson Estate, presented a dozen wines at the London anniversary dinner. He noted the importance of the diurnal temperature range in summer in Marlborough, which was he said one of the key factors for the quality of flavours in the wines. Hart described the company as “modern pioneers” who know how to adapt to changing conditions.

Wine has become a major part to the New Zealand economy, with exports last year worth NZD 1,700 million, making it the fifth most significant contributor to the country’s GDP.

The evening began with the 2017 Stich Sauvignon Blanc, full of tangy fruit and a range of fruits at the passionfruit end of the flavour spectrum. This wine spends three months on the lees, which contributes to its unique flavours.

The Stichbury and Jackson families planted the first vines on Jackson Estate, named after Jackson’s Road in Marlborough, a short drive from the local airport. The Stich Sauvignon Blanc is named in honour of John “Stich” Stichbury, the founder of Jackson Estate. The families have farmed the land for more than 160 years. Cloudy Bay, who many say started the trend for Kiwi sauvignon blanc, is a neighbour.

A highlight of the tasting included two Sauvignon Blancs from the 2001 vintage, one in screw-cap and the other under cork. They were both obviously Sauvignon Blanc, though the wine sealed with cork was more oxidised and had a slightly caramelised flavour. The wine under screw-cap felt younger.

Both wines glowed gold in the glass, a radically different colour from the pale almost clear 2017 vintage. I liked both wines so the cork versus screw-cap argument seemed irrelevant. One must challenge the point of storing Sauvignon Blanc for a long time. It tends to be better consumed young, unless it receives some oak treatment, which is rare in New Zealand. An earlier column looked at examples of oaked Sauvignon Blancs.

Jackson Estate sells around the world, and recently opened a specialist shop in Shanghai, China’s main wine city. The company combines advanced winemaking techniques with a traditional hands-on approach to viticulture.

Techniques include focussing on low yields to concentrate fruit flavours, small batch fermentation, single vineyard wines and minimal intervention in the winemaking process. All fruit is estate grown which means winemaker Matt Patterson-Green can control grape quality and ensure minimal intervention in the winemaking.

Jackson Estate also makes Riesling, Chardonnay and Pinot Noir. The 2001 Riesling under screw cap was enticing and vibrant and had developed those terpene aromas associated with older Rieslings.

Another highlight of the dinner was a chance to taste the company’s two 2007 Pinot Noirs, both under screw-cap. The company has two Pinot Noir vineyards totalling about 4.5 hectares. These wines typically spend between 12 and 18 months in French oak for, the quality of the vintage determining how long.

The 2007 Vintage Widow Pinot Noir is named in honour of the families often forgotten at vintage time as staff strive to make the perfect Pinot. I liked the subtle dried herb flavours mixed with black cherries and vanilla.

The 2007 Gum Emperor Pinot Noir was perfumed and sophisticated, and tasted of violets and black cherries. Both had silky tannins that had integrated nicely, making them very easy to drink. The wine is named after the Gum Emperor moth that lives on the edge of the vineyards.

We have not answered the screw-cap versus cork questions, but I can confirm that Jackson Estate make some fine wines.

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