Yeast in wine cuts alcohol

Australian scientists are developing wines with a lower alcohol content but potentially more flavour.

The Australian Wine Research Institute has discovered a yeast that, when added to fermented grape juice, reduces the alcohol content of wines by up to 4 per cent.

At present, winemakers must resort to the costly method of reverse osmosis if they want to reduce alcohol content and some find that damages the flavour.

Institute managing director Sakkie Pretorius said adding yeast had no detrimental effect on the flavour of the wine and, in some cases, improved it.

"In the worst-case scenario it just tastes like normal. It will not diminish the flavour, in fact it will probably enhance it."

As yeast is already added to wine during fermentation, the cost to winemakers is virtually nil, according to Professor Pretorius.

He said that as the popularity of fruitier-tasting wines increased, so did the alcohol content, as grapes were left on the vine longer and the sugar levels became higher.

Instead of alcohol, the yeast converted some of the sugar to glycerol and gluconic acid, which are already found naturally in wine.

He said there were many benefits of a lower-alcohol wine.

"I don't think it's for people to consume more of it just because they could drink and drive. I think it has more to do with the flavour and what you expect from that wine.

"The second thing is the content of alcohol has a big effect on duties and taxes.

"Of course, some people just prefer less alcohol in it."

Professor Pretorius said the research, although promising, was still in its preliminary stages and full trials of lower-alcohol wines were at least five years away.

He said that if successful, the results of the research would have international appeal.

- AAP