Wine 101: What is Wine?
At its simplest, wine -- and we’re talking about the stuff made from grapes -- is fermented grape juice that convinces us we’re better dancers after a few glasses.
However, at its best, wine reflects the land it came from, and it reflects the hard work and determination of the people who grew it and shaped it into something we love to drink. From grape to glass, we’re here to explain what is going into each glass you pour, and, in future pieces, we’ll talk about the places and processes that turn grapes into wine.
What’s really in a glass of wine?
Water
To start, the vast majority -- 80-90% -- of wine is made up of water, most of which comes from the grape. In some cases, it can sometimes be added in lower quality wines, or to dilute a wine’s alcohol content. A little underwhelming, but there’s a reason Roman soldiers drank wine en masse: it’s mostly water, and it was definitely safer to drink than the local water was.
Alcohol
Usually making up the next 10-15% of wine, alcohol in wine is produced via a process called fermentation, which occurs when yeast is added to the juice produced by crush grapes. The yeast then consumes the sugars in the juice and releases ethyl alcohol -- also known as ethanol, which is the stuff that, let’s be honest, we really love. The amount of alcohol present in a wine also contributes to the “body” of the wine, or how it feels in your mouth. The evaporation of alcohol in a wine also plays a big role in carrying the aromas of a wine to your nose.
Acid
Often not a huge part in wine by volume, acid in wine contributes in a huge way to the “structure” of a wine, which is how the various components of a wine, like the acidity, the refreshing qualities, the tannins (more on those soon), and other components and pieces work to balance each other out. There are some really important acids found in wine, a few of which you can read about below.
Tartaric acid is very important in helping to preserve wine
Malic acid can, in the right amount, contribute green apple flavors to a wine
Lactic acid can add creamy or even buttery flavors to a wine
And it doesn’t end there: if you really want to dive into an Internet hole for the evening, acidity in wine is such an important topic that it even has its own Wikipedia page.
Sugar
Most of the wine we drink is pretty dry -- so dry, in fact, that the sugar levels are too low for the human palate to even register! As it turns out, sugar, which usually makes up anywhere between 15-28% of a grape, plays a pretty important role in wine production: it’s the fuel yeast use to produce alcohol; it’s a simplification, but you can think of it as “sugar in, ethanol out.” In some wines, like dessert wines, there are processes that can be used to keep sugar levels higher in the wine itself, but that would warrant an article all of its own!
Phenolic Compounds
Phenol-i-what? Phenolic compounds -- a.k.a phenolics, a.k.a phenols -- are some of the important and miscellaneous “other” compounds that make up a wine. For the chemistry-inclined, we have Wikipedia to talk about what exactly phenols are, but for purposes of knowing what’s in the wine you’re drinking, here are some of the more important ones:
Anthocyanins: These give darker wines their red and bluish colors. Wines that are more red are often more acidic, while wines that tend towards bluish hues are less so.
Flavonols: The yellowish pigments found in white wine. These increase with exposure to sun, so white wines from warmer climates tend to trend more towards golden hues.
Tannins: These are responsible astringent, mouth-drying feeling you experience while drinking red wines. They typically come from grape seeds, stems, and skins, and can also be imparted by the oak barrels some wines age in. Tannins also form part of the structure of a wine, and act as a natural preservative in wine.
Vanillin: A compound found in oak, can find its way into wine during barrel aging. As you’d expect, it can contribute to giving a wine aromas of vanilla.
Resveratrol: Another compound found in red wine that could -- maybe, I’m not a doctor, and this isn’t medical advice -- provide health benefits. America fell in love with resveratrol sometime in the late 80s/early 90s, because we thought that, despite their love of saturated fats, carbs, and wine, it kept the French healthy. Naturally, instead of examining other factors that might contribute to lower rates of heart disease in the French, like working significantly shorter workweeks, American consumers decided to just start drinking more red wine.
Others
Finally, there are other things, like the carbon dioxide in champagne and other bubbly wines, that don’t fall into any of the above categories. Depending on what they do, some, like the aldehyde formed in Sherry, can either be seen as a fault or a distinct characteristic -- it really just depends on the makeup of the wine, and the concentration of the substance.
There is, of course, much more that has been written, and even more that could be written about “what” exactly wine is made up of. This isn’t meant to be any kind of exhaustive and definitive guide to that topic, but we hope this served as a good introduction -- if you have more questions about wine, feel free to subscribe to our newsletter or email us.