Riesling grapes and leaves

A cure for ageing riesling

Germany and Australia protect vineyards from sun damage

It’s a good thing to age like wine, so the saying goes, but would you want to age like a wine grape? Not if it’s a riesling grape growing under harsh sunshine.

Riesling grapes are struggling with premature ageing, seemingly because of climate change, in parts of Australia where they have previously thrived.

“In recent years young riesling wines have started to show a premature ‘aged’ character,” says Dr Yevgeniya Grebneva, a German scientist working for the Australian Wine Research Institute in Adelaide and the Hochschule Geisenheim University.

Although many aged wines are highly valued; in Australia, consumers enjoy riesling’s refreshing youthful acidity. Its unique ability to develop aged flavours and bouquet over decades is a more acquired taste.

“As riesling ages, it develops a distinctive aroma of petrol,” says Dr Grebneva. “And while that is highly appreciated by connoisseurs in Germany, it is less favoured in Australia, so having these characteristics develop in young wines is a marketing nightmare.”

Intrigued by the new ageing problem, she completed her PhD at the Australian Wine Research Institute where she studied the effect of changing vineyard light conditions on riesling grapes to see if that could be the culprit. Sure enough, she found a direct correlation.

“I applied different coloured shade cloth to bunches of riesling grapes at different times during the growing cycle, changing the light reaching the grapes during ripening,” she says. “Eventually I was able to optimise the ageing potential of riesling wine without negatively affecting its overall quality.”

She hopes her work will help arm grape growers with tools to face some of the viticultural obstacles that come with shifts in growing conditions due to climate change.

For consumers, it will preserve their choice of their favourite riesling style – the light bright high acidity younger wines or the elegantly aged, distinctive bouquet of a wine that has not been forced to mature prematurely.