Got a 'know-it-all' friend? Wine show-offs are likely complete novices when it comes to tasting, study reveals

 Is there anything more annoying than a 'know-it-all' who thinks they're a wine expert?

While you're happily sipping your merlot, they might insist they can taste hints of pepper, plum or even pencil shavings in their glass.

But they likely have no clue what they're talking about, scientists have revealed.

A study has found that novice wine reviewers tend to have high levels of confidence, which then dip when they actually start to properly learn about vino.

Researchers looked at wine reviews from an online website and followed around 30,000 users through each tasting note that they posted online between 2003 and 2012.

They tracked descriptive terms and measured confidence via the language used.

Analysis revealed that as people gained more experience drinking wine, they tended to waver in their assertions.

While they started off being sure of their tasting notes, over time their language began to dip in confidence, integrating phrases like 'I'm not sure' or 'It could be'.

 'They start to realise, 'This is more complex, more nuanced than I thought',' author Matt Rocklage, from Northeastern University in Boston, said.

'There are more things I need to know than I thought I needed to know. That's when you see language start to dip in confidence.'

Eventually, that confidence 'rebounds' and people started to use more definitive language like 'I definitely taste this', he explained.

So, unless they're a certified connoisseur, it's likely your 'expert' friend is calling your bluff.

The study was published in the Journal of Marketing Research.

'There is a U-shaped relationship between experience and confidence,' the researchers wrote. 

'While gaining initial experiences decreases confidence, eventually, with more experience, confidence rebounds.'

The team said they also observed the same U-shaped confidence trajectory among consumers of beer and cosmetics.

Earlier this year, an expert warned it's only safe to drink one glass of wine every 12 months. 

The human body can only safely consume one 'large' glass of wine every year because it is too 'toxic', according to Professor David Nutt, a leading drug researcher at Imperial College London.

He says that if alcohol was invented today it would fail modern food safety standards because of how harmful it is to our bodies.

Studies on the toxicology of alcohol - the adverse effects chemicals have on living organisms - reveal that the 'maximal recommended amount' per year is just one large glass of wine, according to the expert.