Wine Basics: Wine Structure

If you've ever watched Somm or Uncorked or heard a wine buff describe wine, it seems like they inevitably use the words "balanced" or "structured". I always want to say, "What in the world are you talking about?" If you're in that boat with me, I hope this post will help you with two things... I hope it helps you understand what the heck those wine buffs mean and I also hope it helps you understand more what characteristics you like and dislike in a wine. The ultimate goal of learning about wine is to be able to accurately describe what you like, right?

Wine Structure

The four traits that comprise a wine's structure are:

  • Tannin
  • Acid
  • Sugar
  • Alcohol


Way back in the day, I wrote a short post on tannin and what it was. You can find that here. Tannin seems to always be associated with the word "astringent", but basically it's referring to the compound in wine that dries out your mouth and seems bitter. It can also be described as the "biting" sensation that hits the sides of your tongue and back of your jaw. Tannin is a product of the contact between the seeds, skins, and stems and the grape juice during pressing and/or fermentation. High tannins can typically be found in varietals like Cabernet Sauvignon, Syrah, and Nebbiolo. 


Acid is easier for most people to understand because we're familiar with acidic things like citrus fruits, coffee, and soda. I always hear acid described as, "Think about taking a bite of a lemon." For me, my mouth immediately begins to water as I imagine the tartness. This is the key difference between acid and tannin... acid makes your mouth water where tannin causes your mouth to dry. Acidity is typically felt as a zing on your tongue and is commonly found in wines grown in cooler temperatures. A great example of a wine that is commonly thought of as acidic is a New Zealand Sauvignon Blanc.


Residual sugar left in the wine after fermentation is what causes wine to be sweet. Sweetness is identified by the tip of your tongue. It is common for people to confuse sweet and fruity since we typically associate the actual fruit with sugar and sweetness (think of a ripe strawberry). You can truly tell if a wine is sweet by holding your nose and trying the wine... if you can still taste the sweetness, then the wine is actually sweet. Otherwise, it's likely just fruity. Rieslings, especially nice German Rieslings, are often on the sweeter side of the scale and low in alcohol.


Alcohol is a byproduct of yeast eating sugar. Therefore, low alcohol wines tend to be sweet given the residual sugar left in the juice. Low alcohol wines are usually less than 10% ABV while a wine is typically considered a high alcohol wine when it's over 15% ABV. I'd say you probably see that most wines have a 13.5% ABV, which is considered "medium-high" alcohol. High alcohol can be a result of several things, but examples of wines that are commonly high in alcohol are Australian Shiraz and California Zinfandel.

The goal with the traits above is to get them in balance, or rather to not have one that stands out. An unbalanced wine that has too much alcohol will likely burn when drinking and not be pleasant. Or an unbalanced wine whose tannins are out of whack may taste bitter, and who wants bitter wine?! Balance is key!

What do you look for in a wine?