Science or custom? Why not both – studies reveal that there is strong scientific basis to combining good red wine with a juicy high-fat cheese. Also: what does all this have to do with astringency?
Wine and cheese are considered a great match. As is beef sandwiches with pickles, green tea with Asian food, sushi with pickled ginger, oil with vinegar or potato chips with soda. What is common to all of these fantastic combinations? They are a combination of food that causes dryness or roughness in the mouth ("astringency"), mixed with fatty foods that create a feeling of smoothness in the mouth.
Why do these combinations work so well? According to a paper published in 2012, astringent materials such as tannin in wine and green tea, belong to the polyphenol family, which bind to proteins in the saliva that grease the mouth, causing them to group together and harden. This area of the tongue and gums is then left without the fat that usually covers it, creating a rough texture palate.
According to chief author Paul Breslin, extreme feelings of dryness or oiliness in the mouth are unpleasant to us. In contrast, a moderate level of oiliness we will gladly accept, and astringent materials maintain such a level by reducing the amount of the oily materials in our mouth that increase when we eat fatty foods.
Further research found that if you inhibit the interaction between tannin and the salivary proteins, for example by adding certain strains of yeast to wine, one could mitigate the astringent feeling.
Yet it still remains a great mystery: why wine and green tea, that have moderate astringency, manage to reduce oiliness? It turns out that their influence gradually increases their contact throughout the mouth, until the effect reaches a point of saturation. In other words, oral sensitivity to them increases so they react more strongly with the fatty substances.
Another experiment confirmed this conclusion. When study participants drank tea and ate salami alternatively, the sense of smoothness in the mouth caused by the sausage decreased as they drank more tea. However, the feeling grew among those who drank water.
These results illustrate why we do not have a full glass of wine in the middle of eating a tender steak or eat full intact pickles while eating a sandwich: we aim to neutralize the feeling of greasiness at each bite, and clean the palate with small amounts of the astringent material.
What makes a good match?
The question still remains why certain oily foods match well with certain astringent foods and not with others? In other words, why cheese with red wine works better than with green tea? It seems that the answer is primarily cultural - that it comes from such foods that were available at the time in specific areas and certain cultures.
However, according to Breslin, certain cultures may have found the most successful combinations based on the chemical properties of foods, even if they were not aware. "Different kinds of astringents give rise to different rates of growth of astringency. As you repeatedly sample them, one will have a steep rise and the other a shallow rise, depending on the chemical composition of the material and its concentration. It could be that there's a particular mixing of an astringent and a fatty food that determines how strong the astringent is going to be and how quickly it gets there. This is a mystery of gastronomy," he says.
Further research revealed the depth of the neural mechanisms behind astringency. It turns out the trigeminal nerve is responsible for astringency – this is one of the cranial nerves that comes directly from the brain. This is a nerve involved in the motion of chewing and swallowing, but also operates the sensory nerve that transmits touch and taste sensations from the face and tongue.
Blocking this nerve, it turns out, causes a loss in astringency. Cultured murine nerve cells showed a strong response to eight polyphenols that are found in red wine. Each of these polyphenols had a specific chemical residue that without it there would be no astringent sense, or at least a very weak one. The researchers also found that the responses of neurons depended on the operation of G proteins and the entry of calcium into nerve cells via voltage-dependent calcium channels.
Finally, the question arises: what matches better with cheese - white or red wine? Well, the only thing that matches for white wine is its similar color to cheese, because it does not cause astringency. White wine does not contain polyphenols – they are only found in the skins of the grapes, which are not used in the production of white wine. Grape skins are also what give red wine its color.
Beyond the effect of astringency, polyphenols are also antioxidants, and have been proposed as an explanation for the French pardox – having a low heart disease rate despite their high intake of fatty foods.