Key Points:

This is a story about wine and "c" words - controversy, competitions, consistency and camps, not to mention conflict of interest (judges) and consumers, specifically whether or not they've been conned.

It all blew up last week when Wither Hills Sauvignon Blanc 2006 was stripped of its Cuisine five-star rating because the wine entered in the magazine's competition differed from that on supermarket shelves.

This led to the New Zealand International Wine show stripping Wither Hills of the gold medal it had awarded the wine in September.

Then Brent Marris, the Wither Hills winemaker at the centre of it all, resigned as chief judge of the Winegrowers' Air New Zealand Wine Awards and gave back the silver medal the wine won there, plus all its other medals including the gold it received in the Liquorland Top 100 awards. Controversy had snowballed into scandal.

Ask anyone in the wine industry what they think of competitions and you're likely to find they belong to one of two camps.

Those for: "My guess is that the evolution of New Zealand wine would be five or 10 years behind its present state without competitions," says acclaimed wine judge Bob Campbell.

Those against: "Competitions are a joke and we all know it," says outspoken wine critic Keith Stewart.

Campbell says competitions provide buyers and consumers with an objective guide to quality by comparing a wide range of wines, judged blind, with many checks, controls and balances. "I've judged in nine different countries and I think the wine shows in New Zealand and Australia are better than any others."

Campbell says the ingredients of a good competition are experienced judges, a wide range of entries in each class, and stringent organisation - especially "the total brick wall" between the backroom, where the wines are sorted, catalogued and poured, and the front room, where the anonymous samples are tasted.

"There are a lot of rewards in shows and I guess that's why the New Zealand winegrowers support the New Zealand wine awards," says Campbell.

"It provides peer review. The winemakers get new targets to aspire to and I think it's an extremely healthy thing."

Stewart sees competitions as "a total and absolute con" and little more than a surrogate marketing ploy. He points out that they're also a big moneyspinner for the organisers.

Competitions usually charge an entry fee and require competitors to send a case for each wine entered. At, say, $50 an entry, and in a competition where 2000 wines are judged, that can add up.

Then there are surplus bottles - often only two from a case will be used in the competition - that competition organisers can sell or dispose of as they see fit.

Stewart says competitions were useful in the early 60s as a means to improve the quality of New Zealand wine, but that has happened and it's time to move on.

"I stopped judging competitions 20 years ago because they seemed to me to be irrelevant to the future quality of New Zealand wine," Stewart says.

"Top quality wines don't show at competitions because it doesn't do anything for them. They know they make good wine."

For Stewart, measuring a wine against its peers is what happens in the market. "That's where you tell what quality is - the price the market is willing to pay for it."

Judges come in for flak too - mainly when they're also winemakers, as was the case with Marris.

It was a situation Te Mata winemaker and former chairman of the Wine Institute John Buck faced for a decade from the mid-80s.

"I thought it was inappropriate that you should be chairman of judges and an exhibitor, because you can be accused of manipulating the results," Buck says. "It's the most elementary of conflicts of interest. You put your hand up and say: 'I've got a conflict, so I won't exhibit.' You can't run the show and win a prize."

Buck kept Te Mata out of competitions while he was judging and, like many top labels, doesn't enter competitions.

"Candidly, we don't need it. We pulled out and discovered a few years later it never had any impact on the business and never went back."

But many say the issue of winegrower judges picking their own wines in a competition isn't a problem when there is proper blind testing.

"In my view, winemaker judges are not very good at picking their own wines," Campbell says. "I've done a lot of judging and I can't recall ever seeing that."

He says judges don't think about the possible identity of the wines in front of them, because if they do they'll probably get it wrong and fill their head with prejudice that will get in the way of judging.

"Professional judges avoid any thought about what the wine might be. They judge anonymous liquids."

Marlborough Wine Research Centre senior researcher Wendy Parr agrees: "When I do experiments with wine professionals, I find that when there are under 15 wines in a line-up, people can discriminate and they may even pick their own wine.

"But above 15, it's highly unlikely - even for professionals of 40 years' experience who have amazing palate memories."

Parr, who has PhDs in both psychology and wine science and is also a boutique vineyard winemaker, says when she first started research into wine judging she was sceptical.

She had doubts about wine judging practices - in particular aspects such as the order in which wines were judged, and making sure samples were randomised.

But in her observations of contests, she says she has been extremely impressed with the way they are run. And that they do end up with consistent results.

"Wine shows have been a big factor in improving the quality of new world wines," says Parr. "For newer winemakers it's the only way to establish your credibility."

Buck says competitions have a place for large wineries which need medals to appeal to chain and the supermarket buyers in order to move large volumes.

"These are the companies that make lots, show lots, swamp competitions with entries and at the end of it all proclaim: 'We won more medals, therefore we are the best winemaker.'

"Consumers should treat wine show results with a healthy dose of cynicism, because they are marketing tools."

He points out that about half the industry doesn't exhibit in wine shows. "The serious wineries in the world just don't go near them."

Buck says while judges may not necessarily pick their own wines, they are able to detect the style of wine they make. "It's the style that influences their palate, so that style gets preferred and it narrows down the odds to the wine picked being one of theirs.

"But whether they pick it or not isn't the point - the public are entitled to know there is a conflict of interest that they don't declare."

Wine critic Keith Stewart says producing a batch of wine specifically to win a competition was common practice 10 years ago.

"We use to have things called beaker blends, which means they made it in the lab - they made a big enough batch to put it into the competition."

He says the reason it's done is that gold medals are won by having a wine that stands out and is completely different, "something that attracts the attention of the taster in the line-up".

Stewart says the practice still occurs but wineries are upfront about it - indicating differences between batches by calling the better wine something like Sauvignon Blanc 2006 Reserve or Block 6.

"Consistency is not an issue. There is a very simple and long-held standard in the wine industry - you put it on the bloody label."

Stewart rejects arguments that it is difficult to get consistency across batches, pointing out that it is possible with modern technology to blend different batches across different tanks and come up with a consistent blend that is analytically identical before bottling.

Parr notes that when it comes to taste, the way the alcohol, acid and sugar come together providing a wine's balance is key. "If the residual sugar was different people wouldn't necessarily pick it up as sweeter, but they might pick it up as having more weight in the palate."

Much depends on the degree to which the wines are chemically different. "The chemistry in the end will say that they are different, but the human perception - at times depending on the context and other things - means even skilled wine judges wouldn't necessarily pick up the difference."

For Parr the difference between batches comes down to a question of ethics. "If a skilled and competent winemaker picks up the wines are - on either a chemical analysis or sensory evaluation - different enough for them to feel that the consumer is owed a different label, then that's what one must do. It's really an ethical issue of respecting the consumer."

Campbell agrees: "If there is any significant batch variation, they owe it to the public to identify that with a clear batch number or a clear indicator."

In Germany, for example, batch differences are often indicated by different coloured capsules on the bottles.

Campbell says screwcaps also play a part in the debate: "Under cork, if there were two different bottles then one could say: 'Well, hey, it's just the cork.' With screwcaps, every bottle should be pretty much the same."

The issue now is whether the Wither Hills scandal will taint New Zealand's wine industry - the consensus being that what has happened is having a ripple effect.

Parr: "Wine buyers don't want to hear anything questionable about the calibre of New Zealand wines and the soundness of the industry and policing it and so on." Campbell: "It's a shock to an industry that is normally squeaky clean."

Others see some positives.

Stewart: "Hopefully it will let the wine industry have a serious conversation about where they want to go now."

Buck: "I think scandals are always not good - they diminish your generic brand premium in varying degrees. But it's quite a healthy bloodletting and the industry could come out the better for it."