Not all wines are created equal; neither are all wine tasters.

A wine expert's acute sense of taste may mean that expert ratings and recommendations are irrelevant to wine consumers who were not born with the ability to discern small differences in a broad range of tastes, according to a team of international researchers.

"What we found is that the fundamental taste ability of an expert is different," said John Hayes, assistant professor, food science, and director of Penn State's sensory evaluation center. "And, if an expert's ability to taste is different from the rest of us, should we be listening to their recommendations?"

In a taste test, wine experts showed more sensitivity to tastes than average wine consumers.

Hayes said that the participants sampled an odorless chemical -- propylthiouracil -- that is used to measure a person's reaction to bitter tastes. People with acute tasting ability will find the chemical -- also referred to as PROB, or probe -- extremely bitter, while people with normal tasting abilities say it has a slightly bitter taste, or is tasteless.

The researchers, who reported their findings in the current issue of the American Journal of Enology and Viticulture, said that wine experts were significantly more likely to find the chemical more bitter than non-experts.

"Just like people can be color blind, they can also be taste blind," said Hayes.

Hayes, who worked with Gary Pickering, professor of biological sciences and psychology/wine science, Brock University, Ontario, Canada, said that the acute taste of wine experts may mean that expert recommendations in wine magazines and journals may be too subtle for average wine drinkers to sense.

The researchers also found that people who were more adventurous in trying new foods were also more willing to drink new types of wines and alcoholic beverages, but this food adventurousness did not necessarily predict wine expertise. While wine experts were more likely to try new wines and alcoholic beverages, Hayes said they were not more likely to try new foods.

Wine critics typically rate wines on a 100-point quality scale that incorporates a range of characteristics, including tartness, sweetness and fruitiness, varietal typicity and over all liking, among others. Their descriptions of the wines can be specific, highlighting grapefruit or grassy notes, or the balance of sugar and acid. However, according to Hayes, average wine consumers probably cannot discern these subtle differences between wines. While prior experience matters, biology seems to play a role.