You just got home from your day of work, grocery shopping, and the million other things you needed to do. It’s Friday and it’s been a long week, so you make a quick stop at your local wine merchant (ok, not so quick). Someone at the shop helps you pick out the perfect bottle. A dry white wine with ripe fruit, but not too much, maybe with a hint of minerality. At least those are the words you remember him saying to you. You really just wanted something beautiful to counter the definitively not beautiful week you had. You open the bottle, pour yourself a glass, and sit down. You take your first sip – sheer heaven! And sure enough, the bottle just gets better with each sip, and each glass as it continues to open up. Your week has melted away and you wonder how some fermented grape juice could make you feel so happy with the world.
Wine transports us places, lifts our moods, is a vessel of celebration, or a restorative when we’re feeling down. We (humans) have been making wine for at least 8,000 years. Wine stars in various books of literature, is represented in art, and has strong roles in religion, a substance both evil and holy; divisive and unifier.
What makes wine so special? The reality is it’s just water, alcohol, phenolics, maybe some sugar, and flavor and aroma compounds. That’s kind of like saying the Mona Lisa is just oil, poplar, and some color compounds. It’s technically true, but like so many of life’s great pleasures, the synergies of wine’s components transcend any single aspect. That said, if you learn how to focus on each component individually, you’ll be able to articulate what you want with more ease, which will also help you find wines with similar profiles. Eventually, understanding wine better will lead you to drinking more diverse wine styles and can open up your world to things you never knew existed! So let’s get into it a bit. My aim is to give a high level overview of each component and explain the tendencies in wines. (There are almost always exceptions to what I’m saying, but my goal here isn’t an exhaustive list of any possible wine.)
If you can, grab a bottle of wine and take a sip as we talk about each component. Whether or not you can articulate what you’re experiencing yet, your reaction to the wine is largely determined by the following components.
Water
Not the most exciting component, but water comprises the majority of wine (80-85%). Water’s chemical properties help make wine what it is. It is the vessel of all other components in the bottle and why we can drink it. Water also has high specific heat, meaning it takes a lot of energy to raise the temperature of water 1˚C. High specific heat is helpful as it keeps wine from getting too warm in your glass, even if you’re sipping a rosé outside on a hot summer day.
While a crucial component of wine and life, there’s not much to add that will help you find your next great bottle.
Alcohol(s)
Alcohol, specifically ethanol, might be the reason viticulture exists. Fermentation is the process of yeasts consuming sugars and turning them into ethanol and carbon dioxide. Alcohol levels can range from 8% in sweet wines to around 20% in fortified wines, such as Port, with most dry wines falling between 10.5% and 15.9% alcohol. Importantly, excluding fortified wines, the alcohol level in a bottle of wine is inversely proportional to the amount of residual sugar in it. There are other types of alcohol in wine, the most common are higher (fusel) alcohols, such as methanol. Although higher alcohols exist only in trace amounts, they add aromas and complexity to wine. That being said, they’re not really something you can easily seek out, so we won’t go into too much depth here. We’ll explore the various types of alcohol in another post. Someday. Probably.
In addition to greasing conversation with your companions, alcohol keeps the wine protected from microbes and adds body, flavor, and heat to the wine. Indirectly, many of wine’s flavors are by-products of fermentation, so without alcohol, wine would never be much more interesting than the flavor of grapes.
How understanding alcohol helps you understand wine better: high alcohol wines tend to have more ripe fruit. If that’s your jam (get it?), look for wines with over 14% ABV. If you prefer more subdued fruit (meaning you know it’s there, but it’s not the most dominant characteristic), you may want to look for more moderate levels of alcohol, around 12.5%.
If you want to get better at detecting alcohol levels without looking at the bottle, the best way to experience it is through observing heat in the back of your throat. Take a sip of wine. After you swallow, take a short inhale (half a breath). If you feel a lot of heat in the back of your throat, the wine has high alcohol. If there’s just a gentle bit of heat, it’s likely medium alcohol. If you don’t notice any heat, it’s a low alcohol wine. Depending on how low the alcohol is, the wine might have at least a small amount of residual sugar. The nice part about learning to gauge alcohol levels is you have immediate confirmation by looking at the bottle. Unlike aromas and flavors, alcohol levels are easily measured in a lab. One thing to keep in mind: most countries allow for a 50 basis point difference (meaning 0.5%) between the actual alcohol level and what the label says. If you find yourself constantly thinking 14%, but the label says 13.5%, you might be right.
The alcohol level in a wine is also important when pairing wines with food. High alcohol wines are always full-bodied. Very light foods can be completely dominated by a full-bodied wine. For instance, a Central Coast Zinfandel will dominate a light piece of whitefish, making both fish and wine taste worse — the opposite of our goal with wine pairing! Not only reds, but full-bodied white wines can be too overpowering as well. Alcohol also creates a drying sensation as it evaporates, so it’s best to avoid spicy foods with high alcohol wines.
Tannins
Tannins are polyphenols that exist in many food products including chocolate, coffee, and tea. In nature, they help plants protect themselves from overzealous herbivores as well as pathogens. When we consume tannins, they bind with proteins in saliva, creating the feeling of astringency (the proteins are what help saliva lubricate your mouth). When tannins are either unripe or too plentiful, this sensation is off-putting (and thus a deterrent to a hungry animal). Depending on the amount, length, type, and shape of the tannins, we may feel anything from a soft velvety coating inside our mouths to a drying sensation like we sucked on a piece of gauze. We often use words ranging from green, chalky, or grippy, to ripe, supple, smooth, or fine to describe tannins.
Red wines are most well-known for their tannins, but orange wines have them too. White wine and rosé can have them, but generally in low amounts that don’t have a major impact on our experience of the wine.
Tannins in wine come mostly from grape skins, but also seeds, stems, and to a much lesser extent, oak. It turns out tannins are complex little things and scientists are constantly learning more about how they function and evolve in the wine. The previous belief that tannins simply polymerized (connected with each other and grew larger) in bottle until they fell out of the wine is an oversimplification. Some tannins do fall out of the wine, but in ways we don’t yet understand fully, tannins also change in shape and structure, making aged wines less astringent. Anthocyanins, the phenols that give red wine its color, also bind with tannin, which is part of the reason red wines turn to brown as they age.
A brief side note: if you’re wondering why rosé has color, but not much tannin, it’s because tannins are not water solvent, and the brief duration of skin contact is done before fermentation, when alcohol is either minimal or absent.
How does understanding tannins help with appreciating wine? We each have our own sensitivity to tannins. Some people are drawn to very tannic wines, others find them too overpowering, unless accompanied by specific types of food (e.g. a rare steak). Not only the level of tannin, but the type of tannin can help you find more wines you like. If you have access to a good wine shop, telling the person working there about a wine you liked the tannin structure of can help them find something else you like. This is especially true if you liked the tannins, but found something else about the wine off-putting.
Tannins are important for food pairing as well. The combination of a big Cabernet Sauvignon with a rare steak is a classic for good reason. Tannins act as an astringent, thus drying out your mouth, which enhances the perception of the steak’s juiciness, making it seem more delicious. You generally want to pair high tannin wine with something juicy. A well-done steak will not serve the same purpose. Fattier steaks are more delicious with high-tannin wines, as the tannin helps cut the fat. A ribeye will serve you better than filet mignon. Who am I kidding, besides in a Beef Rossini, when is a ribeye not better than filet mignon?
Acidity
When we consume something acidic, our mouths release saliva to protect our teeth. The saliva cleans out our mouths, which feels refreshing. Acidity is also one of the major components that allows wine to age, which is especially important for white wines. While there are many types of acids in grapes the two most common are tartaric and malic acids. Tartaric acid is critical to wine. Malic acid, however, can be harsh on our palates and is sometimes converted into lactic acid through a process called Malolactic Fermentation (aka ‘Malo’ or sometimes MLF).
While pH isn’t the most telling measure of a wine’s acidity, it is the most common and easy to understand. Because pH is an inverse logarithmic scale, lower pH indicates higher acidity. An acidic wine may be as low as 2.7 pH and a wine with lower acidity may be as high as 4.3, with most wines falling between a 3.0 and 4.0. Acidity is higher in white wines. In part it is due to higher levels of potassium in grape skins, which neutralizes some of the tartaric acid in red wine (remember, white wine is made with minimal, if any, skin contact). Also, almost all red wines undergo MLF, but most white wines either don’t at all, or only some of the wine undergoes MLF. High acidity also enhances our perception of tannin and reduces our perception of residual sugar, meaning too much acidity in a red wine may make the tannins unapproachable, while high acidity in a white dessert wine keeps the wine from being cloying.
Understanding acidity in wine can help you find more varietals you like. For instance, if you had a Premier Cru Chablis and loved it, you might find also enjoy other high-acid varietals, such as Riesling and Chenin Blanc. Acidity is also crucial with food pairing. High acidity can help cut fat and restore our palates. For instance, Nebbiolo (high acid, high tannin red grape) is an excellent partner to lamb. Sauternes is a classic partner to foie gras (in this case, both for its acidity and residual sugar). One of my favorite surprise pairings was at Californios in San Francisco, where they paired a Meursault (white Burgundy) with Wagyu. It was absolutely mind-blowing!
Carbohydrates (Don’t worry, there aren’t many!)
Most wines are produced in a dry style, meaning the majority, if not all, sugar is fermented into alcohol. Wines that are marketed “low carb wine” are really taking advantage of a fact inherent to dry wine. Don’t fall for it, you’re probably spending more money per bottle for the same or lower quality of wine. Lower end wines such as the typical White Zinfandel might have more residual sugar, as will great wines such as some Rieslings, Champagne, Chenin Blanc, and of course, dessert wines.
That being said, when a wine does have residual sugar (often abbreviated RS), the sugar adds complexity to the wine. It can help round out high levels of acidity, such as in German Rieslings, and it also adds viscosity to the wine, making it feel a bit heavier in your mouth and adding body. Quality wines made with residual sugar are often excellent accompaniments to a variety of foods, including fatty foods and spicy dishes.
Terpenes, Esters, and Thiols, oh my!
These tiny things comprise the smallest percentage by volume of wine (about 0.5% of volume), but create the most differentiation between wines. These are all of the aroma and flavor compounds that makes wine what it is and a bottle of wine unique. There are more than 9,000+ molecules that impact the flavor of wine, but we’ll stick to the major groupings here.
Esters are often credited with lots of flavor contribution, but the reality is they tend to be short-lived and mainly impact youthful, fruit-driven styles of wine. In fact, while fruit esters contribute pleasant aromas to youthful wines, they become soapy with time as the carbon chain increases.
Thiols, also known as mercaptans, are responsible for both attractive and repugnant aromas in wine. Some mercaptans add various fruit aromas, e.g. black currant, passionfruit, and grapefruit. Others lead to notes of reduction in the wine, such as garlic, cabbage, or rotten eggs. Our olfactory senses are extremely sensitive to thiols and are detectable in miniscule quantities: about 10 parts per billion. Thiols are quite complex, both in their formation during fermentation and their preservation during winemaking, but are not yet fully understood.
Terpenes give us some defining aromas: rose, lychee, lavender, and eucalyptus. While winemakers can integrate various practices to enhance or diminish the presence of terpenes, their basic characteristics are strongly correlated to their varietal. For example, rose and lychee notes are telltale signs of Gewurztraminer in a blind-tasting.
Aromatic compounds are what drive what we love about wine. Being able to recognize various aromas and flavors in wine will help you find more wines with similar profiles. The opposite is also true, you may find what you want to avoid in wines. For instance, I find methoxypyrazines (green pepper) off-putting in red wines, so I avoid cool climate/cool vintage Cabernet Sauvignon.
Each of the above components deserves a book unto itself. The above is an introduction for you to begin exploring wines with more, wait for it, structure! As you progress in your wine journey, you’ll want to learn more about each component.