Glittering hope for wineries

Hennie and Celia Bosman hope the crushed-glass trial will give their winery an edge. Picture / Simon Baker

A glass of wine a day is meant to be good for you. Now the glass may prove to be just as good for the wine.

In what is believed to be a world-first, finely crushed glass has been laid at the foot of grapevines in New Zealand to try to improve ripening of the fruit, and therefore quality of the wine.

The trial was dreamed up by recycling company TerraNova after discussions with Canterbury's Sandihurst Winery, about 20km inland from Christchurch. It is attracting widespread interest from winemakers overseas.

Lincoln University's Centre of Viticulture and Oenology, which was already trialling crushed mussel shells in the same way, was approached to design and run the crushed glass experiment at Sandihurst.

The idea is that the glass will reflect light and heat to assist the natural ripening of the grapes, as well as combating frost and weed growth.

Glen Creasy, who is leading the trial for the university, said he was excited by the idea's potential.

"If we find positive effects here, the potential is for it to be used everywhere," Dr Creasy said.

"We may see some effects in this harvest, coming up in March-April, but really we won't know the full effects ultimately for a few years."

It was also hoped the glass could help to produce riper grapes without higher alcohol levels in the wine.

"The more sugar you have, the higher alcohol the wine. So if we could have more flavour and lower sugar, we have a wine with less alcohol that is just same quality, if not better."

TerraNova chief executive Richard Lloyd, who owns a pinot noir section of the Sandihurst Winery where the trial is taking place, believes the use of glass could provide a solution to the huge amount of surplus glass generated by the rapidly growing wine industry.

Wineries stockpile thousands of empty bottles in addition to those filled with wine and sold.

"I see it as an opportunity to close the loop and ... to be able use [the bottles] back on the wineries where they were generated in the first place," Mr Lloyd said.

Sandihurst Winery owners Hennie and Celia Bosman jumped at the chance to take part in the trial, and believe it may give them an edge in their wine production.

Mr Bosman was faced with the mammoth task of laying the 20,000 tonnes of green and white glass, crushed to the size of crystals just bigger than sugar, at the base of the pinot noir grapevines.

"It all depends on the degree of improvement to decide if it is worth it. It has still got to be ... profitable.

"We could well have the situation where we have a mobile crusher going around to wineries and actually crushing up all the glass."