New Zealand viticultural technique could combat effects of global warming

by Marja Brouwer

Bron: Drinks Business, Phoebe French

Dr John Forrest, the creator of a viticultural technique used by New Zealand wineries involved in a seven-year project to produce premium wines with naturally lower alcohol, has said that it’s capable of helping wineries across the world “to ameliorate the effects of global warming”.
Dr John Forrest thinks there is global potential for the technique he has developed.
The project – a NZ$17 million research and development initiative funded by New Zealand Winegrowers and the New Zealand Ministry for Primary Industries’ Primary Growth Partnership – is now four years in to its seven year total.

While Forrest views the lighter wines born out of the project as a “new category in wine,” the technique itself can aid the entire industry.

The method, which involves the removal of selected leaves to reduce the photosynthetic ability of the vine and thus the sugar accumulation, can be used by wineries that are struggling to control the alcohol levels in their wines due to global warming.

“I am confident to state that the process can be universally applied to white grapes,” said Forrest, who has spent the past three years attempting to achieve similar results in red wine, in his case, Pinot Noir.

“We’ve had enquiries from California from wineries that are achieving around 16-17% alcohol in their Chardonnays,” he said.
When asked if the technique could be applied to white grapes with lower acidity that that found in Sauvignon Blanc – the wine Forrest was showcasing – he said that it could indeed be used universally.

“We found that reducing leaves can actually increase acid drop by 5%. The grapes are harvested at same time – we’re not picking early – so it allows the same time as normal wine for the grapes to develop,” he said.

This means that while the sugar accumulation is reduced, the de-acidification, phenolic ripeness and flavour development are unaffected.

Forrest also told db that he experimented with the technique using Chardonnay grapes during an El Niño year in New Zealand three years ago.

“We produced one Chardonnay at 13% ABV and another lighter version at 10%. It proves that the technique had application across the entire industry to ameliorate the effects of global warming”.

Lighter wines

Forrest began researching methods of producing lower alcohol wine 10 years ago. After witnessing the popularity of 8.5% Kabinett Riesling, he believed that if he could produce a lower alcohol Marlborough Sauvignon, there would be a strong demand for the product.

“I started off in the winery by modifying the juice and trying to restrict the sugar and alcohol potential. The problem is that by doing that [de-alcoholising] you remove so much else”.

After three years’ of research, Forrest was still producing wines that were “thin and unsatisfying” and decided to change tact.

After reading a paper from a professor at the Geisenheim University in which it was recorded that small effects in lowering sugar in German Riesling could be achieved though leaf removal, Forrest began experimenting.

The result is his The Doctors’ range – named after both himself and his wife Brigid who are doctors.

“Our object from day one was to produce premium lighter wine and I think we’re very much on route to achieving this,” said Forrest.

When asked if reducing the alcohol by around 4-5% really does make a difference, Forrest gave the example of a gastro pub owner in Suffolk who stocks Forrest wines via local supplier Adnams.

“He told me that by stocking a lighter wine, he was picking up sales where he was previously losing them. He was getting a second glass of wine when before he was only getting one.

“He still stocks my higher strength wines and sales of those haven’t been affected,” he said, stressing that stocking a lighter wine wouldn’t damage sales of normal strength wines.

But will consumers really opt for a lighter wine when there’s only a 4-5% difference in alcohol?

Forrest states that as soon as he reduced alcohol below 10%, people seemed much more willing to try it.

Like the £9.99 phenomenon, “the moment you say a wine is below 10% alcohol suddenly people become interested,” said Forrest.

His first light Pinot Noir was released in July last year in New Zealand and will be in the UK later this year.

“Our lighter wines now account for 60% of the winery’s total production,” said Forrest, who added that the 2018 Pinot Noir was oversold.

Forrest’s technique

After developing his technique for naturally lowering alcohol in white wines, Forrest gave the intellectual property rights to the lighter wines project.

He found that by removing two to three leaves in the middle of a shoot, the plant cannot compensate and the sugar is naturally lowered.

“Out of the 14 to 15 leaves, the first leaf comes out around 20 September while the last leaf doesn’t develop until March.

“Because of that, the leaves don’t behave in the same way. I like to call the bottom leaves ‘the 70-year-olds’ and the top leaves the ‘7-year-olds’.

“The middle leaves, ‘the 20-30 year olds’ do the most work. All the leaves have a different photosynthetic ability, so if you remove two to three leaves from the middle that are best at photosynthesising, the plant cannot compensate.

“This means that at harvest you achieve 17% sugar as opposed to 23% which produces a 9% ABV wine compared with a 14% one”.

Forrest has commercialised this technique by repositioning the canes in the winter, moving them up by a foot. In so-doing, he is able to run the motorised trimmer across the top, cutting off the right leaves at no extra cost.

Around 20 wineries are now using Forrest’s technique, while the project is also experimenting with irrigation control and yeast genetics in order to produce naturally lower alcohol wines.

Bron: Meininger

How is New Zealand doing when it comes to low alcohol wines? Jeni Port looked into the matter for Meininger. It is widely assumed that to make a wine lighter in alcohol all you need to do is pick the grapes early. Simple. It seems...

If only it were. In Sauvignon Blanc, for example, what might taste smooth on the tongue at 13 percent alcohol becomes hard and acidic at 9.5 percent. The grape’s mouth-pleasing grassy signature transforms at a much lower alcohol into something more vegetal, to the point of tasting unpleasant.

With lower alcohols, wine tends to perform a 360° backflip in the mouth, which is a problem for New Zealand winemakers, who have ambitions to be the world’s top producer of premium lower alcohol — defined as less than 10 percent alcohol by volume — and lower-calorie wines by 2021. “We are seeking to own this category,” says Dr David Jordan, viticultural scientist and programme leader of lighter wine research at the 2017 Romeo Bragato Conference in Marlborough.
Growing taste
The research is a NZ$17m ($12.3m) seven-year study being conducted under the auspices of New Zealand Winegrowers with joint funding from the Ministry of Primary Industries. Now in its fourth year, the study has so far revealed that premium wine drinkers in New Zealand and five of its major wine markets — Australia, UK, Sweden, Canada and the US — have a growing taste for lighter wines. New Zealand is one of the biggest supporters of the category, with domestic lighter wines representing 2.6 percent of total wine sales.

“For most markets,” states an interim report, “consumers of lighter wines skew slightly female, typically enjoy drinking premium wine two to five times a week, and are more likely than average to drink New Zealand Marlborough Sauvignon Blanc.”

The New Zealanders are nothing but ambitious with the project. The quest to make wines lighter in alcohol must be done entirely by “natural” means, without any resort to artificial manipulation.
Eighteen makers are involved in the trials, mostly from bigger companies such as Villa Maria, Selaks (owned by Constellation Brands), Wither Hills (Lion Nathan) and Stoneleigh (Pernod Ricard). But also included is the leading player in the field, Marlborough-based Forrest Wines, who has done more than any producer to explore the style. It is Forrest that those in the research programme looked to for guidance. “We started in 2006 and the first year we picked Sauvignon Blanc at 19 brix (10.6 baumé) and for us the wine was unripe,” says Beth Forrest, daughter of the winery’s founders, Drs John and Brigid Forrest. “We were battling high acid and there was a thin palate.”

Beth and her father attended the International Riesling Symposium in Rheingau in 2007 and inspiration struck. “They [German makers] were struggling with rapid sugar ripening in their Riesling in the advent of global warming, and they had started trials on vine manipulation, taking the leaf ratio crop back to slow down soluble sugar accumulation in the vine,” explains Beth.

Less canopy
Back home, the Forrests introduced vine leaf removal to shock the vines into slowing down their rate of sugar accumulation. Today, canopy reduction — vines are trimmed at veraison to half their size — is one of the mainstays of the New Zealand lighter wines programme, reducing alcohol, acidity and aggressive green characters. Looking at soil type and irrigation methods has also been rewarding. Deep soils with high water-holding capacity accumulate sugar more slowly, while short periods of no irrigation at key vine growth stages has been shown to delay sugar accumulation without affecting yield or quality.

When it comes to tasting the results of the lighter wine research so far, some producers are clearly doing better than others. Villa Maria 2016 Lighter Private Bin rosé (10 percent alcohol) is the company’s top-selling rosé, and tasters at the Bragato Conference were hard pressed to fault its colour, crunchy cranberry, raspberry flavour or length.

The real test comes with a grape like Pinot Gris that depends on ripeness for its textural appeal. Two 2016 Gris wines shown in the tasting — Wither Hills and Stoneleigh — had a true-to-form profile. But Sauvignon Blanc was the most inconsistent in the tasting and appears difficult to deliver in a lower alcohol form.
Greater knowledge
In the winery, winemakers involved in the trials have uncovered two important contributors to a quality lighter wine: the presence of oxygen early in a wine’s fermentation can reduce ethanol by around two percent, compared with oxygen-stripped juice. Ethanol can also be reduced by manipulating how yeasts — one group of yeasts can respire sugar, a process that does not result in ethanol formation.

The second major breakthrough has been the role of skin contact. Not only can skin contact influence wine texture and aroma, but it could be a potential substitute for the loss of texture and body in lighter wines.

Once New Zealand has developed its lighter wines, it needs to sell them. Originally labelled “Lifestyle Wines”, they’re now known as “Lighter Wines”. Will they take off? There are three more years of trials and research before the market will decide”