Savvy research on sav blanc

The fruity taste of New Zealand sauvignon blanc lasts longer if the wine is kept refrigerated, says a Plant & Food Research team.

A summary of findings from the first six years of the sauvignon blanc research project was presented at the Romeo Bragato wine conference on Saturday.

The science leader for the programme, University of Auckland professor Richard Gardner, said Marlborough sauvignon blanc contain high levels of thiols called 3MH and 3MHA.

The thiols are what gives the wine its unique ripe fruit flavours and are not present until fermentation, he said.

The sweet, sweaty passionfruit flavours in the wine were attributed to 3MHA, he said.

"If there's a compound you want to play games with to change things, thiols would probably be it and 3MHA is probably the most important."

The research team did not yet know how the 3MH and 3MHA thiols were created, he said.

Tests had shown 10 times more 3MHA was present in wine from grapes which had been machine harvested rather than hand picked.

Another Auckland University professor working on the project, Paul Kilmartin, said it had been found that 3MH was unstable and broke down quickly in the bottle.

About 70 per cent of 3MH and 3MHA was lost after 12 months, and after two to three years it would disappear completely, he said.

The loss of the thiols meant the ripe fruit flavours also disappeared from the wine.

The loss of thiols was slowed if the bottle was refrigerated, he said.

The "Sauvignon Blanc II research problem" would continue to build on the previous studies and would run for the next six years.

It has almost $9 million of government funding, and New Zealand Winegrowers will pitch in $400,000 a year as well.

Dr Gardner said he was not sure whether all the questions they had about sauvignon blanc would be answered in the next six years.

"I'd love to be able to say we'd be able to get there but it's pretty bloody complicated. We can't help but get closer to it, but I would have said six years ago that we would have got it nailed – but I would have been wrong."