The more one delves into the subject of wine and food pairing, the more frequently one finds conflicting recommendations. Optimal (and yes, even ideal) wine and food pairings are not just a matter of culinary heritage. There is real science behind certain foods and wines going together beautifully.
On one level, food and wine pairing addresses the aromatics of the dish and beverage. On a more basic (and more important) level, the weight and body of the wine must work well with the dish. However, matching a wine’s structure to the dish is, arguably, of greatest (if most basic) importance. This has to do with pairing acidity, residual sugar levels and tannin levels to the core ingredients of the food. The chemical interplay between food and wine and their interaction with human physiology work to create a textural synergy.
Are the most common pairing recommendations based in these principles? Are some merely red herrings? The purpose of this series is to tease out the red herrings in food and wine pairing recommendations by exploring the science underlying food and wine pairing. This will provide a deeper, more meaningful insight into the art of food and wine pairing. In the ever-changing culinary trends of our times, this understanding would be far more useful to a wine and food enthusiast than any singular, absolute pairing rules.
Focusing on Tannins
The first pairing I wanted to explore is one of tannic wines (Barolo, Aglianico del Vulture, Cabernet Sauvignon, etc). There are three very common pairing recommendations for these types of wines: big, red meats (protein), fatty dishes and salty dishes. Are any of them red herrings?
Tannins are a category of chemicals called polyphenols. They create a very drying, astringent sensation in the mouth. This is a tactile sensation and should be distinguished from “bitterness” which is a flavor. Logic dictates that a food which tames the astringency of a very tannic wine would be an ideal pairing for such a wine.
To help sort out fact from supposition, I spoke to Bruce Bryant, Ph.D., Senior Research Associate at the Monell Chemical Senses Center in Philadelphia, PA. He agreed to engage in some educated speculation with me.
Dr. Bryant has been studying oral sensation over the last dozen years. He focuses on the trigeminal nerve, which conducts temperature, touch, pain and irritation (such as the perception of spiciness) from the inside of the mouth. True gustatory, or taste, sensation is limited to the tip of the tongue, which is derived from different embryological parent cells and sends its sensory information through two other nerves.
First, it’s important to understand how and why tannins produce an astringent sensation. Polyphenols are known to interact with proteins. They denature them. Highly tannic wines (those with high polyphenol content) feel astringent for two reasons, Dr. Bryant explains: To a limited extent, they interact with proteins in saliva, causing them to fall out of solution. As a result, saliva loses some of its lubricating ability. However, this is a minor component of the interaction. More important, tannins interact with proteins on the surface of the mucosal cells which line the insides of the cheeks and some other parts of the oral cavity. This alters the surfaces of these cells, making them more “wrinkled”. The lubricating capacity of saliva cannot overcome this. Consequently, we feel a greater amount of friction between the insides of our cheeks and the surfaces of our teeth – and to a lesser extent between the gum and tongue. This, according to Dr. Bryant, contributes more significantly to the tactile sensation of astringency. Thus, astringency is a tactile sensation due to textural changes in the mouth lining rather than a significant drying.
When consumed with lean, (typically red) meats, the wines might feel less astringent likely because the polyphenols bind to the proteins in the meat. But there are some caveats. Dr. Bryant explains:
“There is a difference between rare and thoroughly cooked meat. Cooking denatures the protein. Raw meat has more soluble protein, which is more accessible to the polyphenols.”
Protein is still very likely to reduce the astringency of tannic wines because it reduces the amount of tannins that cause the wrinkling of the cells lining the mouth:
“I think that the proteins are going to complex with the polyphenols and reduce their content in the mouth, making them less available to affect the mucosal surfaces in the mouth. That is the simplest chemical interaction which reduces the polyphenol content.”
Adding a Dash of Salt
But what about salty foods? How can they improve the texture of the food and wine pairing? Do the sodium and chloride bind with the polyphenols and reduce their astringent quality?
“I don’t think there is much in terms of chemical interactions [to account for softening of a wine’s astringency]. We know that salt inhibits bitter receptors. It may mask the bitterness centrally [during the higher processing of the sensory data in the brain] and it also inhibits the bitter receptors [on the tongue],” Dr. Bryant explains.
Bitterness and astringency are completely different things. There are plenty of tannic and astringent wines which do not have a bitter flavor component. “If there is a bitter component to the wine, then that will be reduced a little bit by the sodium,” says Dr. Bryant.
He also points out that phenolic groups are not prone to chemical interaction with salts by virtue of chemical stability at the places where salts might interact. So salt, by itself, would not be expected to reduce a wine’s astringency. However, high concentrations of sugar, acids or salts in the mouth induce salivation. Saliva carries proteins which may interact with and reduce the tannins. A compound process may be at play with salty foods but Dr. Bryant’s thinking seemed to be that these processes would probably be less effective at softening a wine’s astringency than a piece of meat might.
Finally, we discussed the ability of fats to reduce the astringency of tannic wines. “To a certain extent, they can act as lubricants. I think that to a certain degree, you relieve some of the friction by the addition of oils,” Dr. Bryan tells me. In other words, the polyphenols are still acting on the cells lining the mouth and “wrinkling” their surfaces, but we feel it less because of the lubricating action of the oils and fats in the dish. He does not think there could be any chemical interaction between fats and polyphenols that would reduce the amount of polyphenols or their potency to diminish astringency.
There are a number of things that happen when a sip of wine and a bite of food are in the mouth at the same time. I’ve tried to address a few basic interactions that have to do with texture and mouthfeel. On the most empirical level, it seems that lean, rare meats are most likely to affect a wine’s astringency.
While all three substances contribute differently to the textural perceptions of a food and wine pairing, the most obvious red herring in this examination would seem to be fatty foods as they only mask astringency by lubricating the surfaces of the mouth. They do not affect the wine in a definitive chemical way. Coming in as a somewhat distant second is salt. Its interaction with polyphenols is considerably weaker.
Fats are essential to cooking. It’s hard to find an absolutely fat-free piece of meat (nor would you want to, as fats do add to flavor, though nobody has explained how, yet). Cooking without any salt would make for bland cuisine even though salt is naturally found in some amount in all the things humans eat. So while fatty foods are the most obvious candidate for a red herring here, it would be safe to assume that a piece of rarer meat will be a very safe (and possibly rewarding) pairing recommendation for tannic wines.