It may seem like a simple question (or an obvious one) but it’s worth asking. Wine is complex and contains over 1000 different compounds. Sounds like a lot of ingredients - and it is - but they are necessary: trace amounts of many elements combine in intricate chemical reactions that result in the world’s most complex beverage (sorry beer lovers!). Wine requires some decoding to help us better understand and enjoy it.
At its most basic level, wine is fermented grape juice - kind of like how kombucha is fermented tea.
Here’s what the formula for fermentation of wine looks like:
Here’s what’s in an average bottle of wine:
Wine is about the senses - it’s about pleasure. It’s about aromas, and flavours and the ability. The compounds that matter most to the enjoyment of wine from the list above are the acids, tannins, phenolics, plus the ethanol, of course. Here’s a quick look at how these fundamental components are actually sensed in wine.
Acid allows the wine to achieve balance between the fruit flavours, any sweetness, and tannins. Acid makes wine refreshing, helps it pair well with food, and also preserves the wine if it is to age in a cellar before drinking. The all-important aroma and flavour esters that make wine smell like honeysuckle or taste like blackcurrant are derived from the acids in wine. Malic (think green apple) and lactic acids (yogurt) are the most common in wine. To feel acids in action, bite a lemon slice - you’ll note your mouth fills with saliva, which is simply your body’s way of diluting the harsh acid. All wines have acidity, but wines from cooler regions tend to have higher levels. Wine grapes like Riesling and Pinot Noir have high natural levels of acidity, while others like Gewurztraminer and Grenache present softer acid profiles.
Light wine with high acidity from cool-climates
Tannins are present in the skins, seeds (also known as pips), and stems of grapes. Tannins can have a bitter flavour and an astringent texture. The best way to understand tannins is to chew a piece of banana skin - you’ll immediately sense the mouth drying, grippy feeling. Tannins dessicate or dry out the palate, which is the opposite effect of acid. Tannin levels vary in wines, and are seldom present in whites. Some red wine grapes are rich in tannins - like Cabernet Sauvignon or Nebbiolo - and some have much lower levels, like Pinot Noir and Grenache. Tannins help give the wine structure, mouthfeel, and preserve wine as it ages. Tannins contribute to the texture in wine, and can be gritty and chewy, or smooth and silky.
Wines rich in tannins and body
Phenolics is a term for a wide range of compounds that affect the colour, taste, and texture of wine. Tannins are a kind of phenol, as are anthocyanins - the pigments that give wine colour. During the grapevine’s growing season, sunlight increases the concentration of phenolics in the grape, which contributes enormously to the flavour, balance, and quality of the finished wine. That’s why it is said that “wine is made in the vineyard” because farming grapes to an optimal level of ripeness (meaning the phenolics are ripe and flavour is fully developed) is a true art form and critical to the enjoyment of wine.
Ethanol (this is the kind of alcohol in wine) and glycerine are responsible for wine’s body and mouthfeel. The percentage of alcohol by volume varies from 5.5 per cent (as in a sweet bubble wine like Moscato d’Asti), to 9 percent (as in a medium sweet Riesling), to 12.5% (as in Chablis), or up to 15.5% in wines like Zinfandel or Amarone. Think of body like milk: skim milk is light in body, 2 percent is medium and homogenized milk is full bodied. The greater the alcohol percentage, the heavier the body. A medium weight wine usually falls into the 12.5 to 13.5 percent range. Higher alcohol wines usually come from warmer growing regions and can be spotted by the spicy warmth in the throat after you have sipped.
Wines with distinct alcohol levels
In 2016, 259 million hectolitres of wine was produced around the world. That’s an ocean of wine. To put it another way, that’s 2,877,778,000 billion cases, or 34,533,336,000 bottles, which is roughly 173 billion glasses of wine made each year. And all this for a global population of 7.5 billion people! Next time you enjoy one of those 173 billion glasses of wine, take the time to assess the levels of acid, tannins, phenolics and alcohol - for the purpose of science, of course!