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Wine-tasting: it’s junk science

Every year Robert Hodgson selects the finest wines from his small California winery and puts them into competitions around the state.

And in most years, the results are surprisingly inconsistent: some whites rated as gold medallists in one contest do badly in another. Reds adored by some panels are dismissed by others.

Over the decades Hodgson, a softly spoken retired oceanographer, became curious. Judging wines is by its nature subjective, but the awards appeared to be handed out at random.

So drawing on his background in statistics, Hodgson approached the organisers of the California State Fair wine competition, the oldest contest of its kind in North America, and proposed an experiment for their annual June tasting sessions.

Each panel of four judges would be presented with their usual “flight” of samples to sniff, sip and slurp. But some wines would be presented to the panel three times, poured from the same bottle each time. The results would be compiled and analysed to see whether wine testing really is scientific.

The first experiment took place in 2005. The last was in Sacramento earlier this month. Hodgson’s findings have stunned the wine industry. Over the years he has shown again and again that even trained, professional palates are terrible at judging wine.

“The results are disturbing,” says Hodgson. “Only about 10% of judges are consistent and those judges who were consistent one year were ordinary the next year.

“Chance has a great deal to do with the awards that wines win.”

These judges are not amateurs either. They read like a who’s who of the American wine industry from winemakers, sommeliers, critics and buyers to wine consultants and academics. In Hodgson’s tests, judges rated wines on a scale running from 50 to 100. In practice, most wines scored in the 70s, 80s and low 90s.

Results from the first four years of the experiment, published in the Journal of Wine Economics, showed a typical judge’s scores varied by plus or minus four points over the three blind tastings. A wine deemed to be a good 90 would be rated as an acceptable 86 by the same judge minutes later and then an excellent 94.

Some of the judges were far worse, others better – with around one in 10 varying their scores by just plus or minus two. A few points may not sound much but it is enough to swing a contest – and gold medals are worth a significant amount in extra sales for wineries.

Hodgson went on to analyse the results of wine competitions across California, and found that their medals were distributed at random.

“I think there are individual expert tasters with exceptional abilities sitting alone who have a good sense, but when you sit 100 wines in front of them the task is beyond human ability,” he says. “We have won our fair share of gold medals but now I have to say we were lucky.”

His studies have irritated many figures in the industry. “They say I’m full of bullshit but that’s OK. I’m proud of what I do. It’s part of my academic background to find the truth.”

Hodgson isn’t alone in questioning the science of wine-tasting….

 

So why are ordinary drinkers and the experts so poor at tasting blind?

 
Part of the answer lies in the sheer complexity of wine. For a drink made by fermenting fruit juice, wine is a remarkably sophisticated chemical cocktail.
Dr Bryce Rankine, an Australian wine scientist, identified 27 distinct organic acids in wine, 23 varieties of alcohol in addition to the common ethanol, more than 80 esters and aldehydes, 16 sugars, plus a long list of assorted vitamins and minerals that wouldn’t look out of place on the ingredients list of a cereal pack. There are even harmless traces of lead and arsenic that come from the soil.

 

Three of wine’s most basic qualities – sweetness, sourness and bitterness – are picked up by the tongue’s taste buds. A good wine has the perfect balance of sweet from the sugar in grapes, sourness from the acids, particularly tartaric and malic acid, and bitterness from alcohol and polyphenols, including tannins.

Many wines are more acidic than lemon juice and are only palatable because that acidity is balanced by sweetness and bitterness. “It’s the holy trinity of the palate – sugar, acid and alcohol,” says Dr James Hutchinson, a wine expert at the Royal Society of Chemistry…..

The Guardian: Read the full article

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