Cellaring or aging wines is an experience in the complexity of the interactions that occur in wine that make wine the unique living beverage that it is. The wines you chose to age are not necessarily the wines that taste good now, in fact, they may have sharp acidity, high tannins and alcohol and taste entirely too sweet, but given 5, 10, 20 or even 30 years, and those characteristics will develop and create new flavors and aromas. While the flavors you taste in an aged wine may be a surprise, knowing if a wine will age well or not can easily be determined by understanding some of the fundamental characteristics of wine.
When you first begin buying wines for a personal collection, you may start out buying wines that you like based on varietal or style and that you plan on drinking within a few months or a year. However, if you are like most oenophiles and are obsessed with wine shopping, you are going to build a collection fairly quickly, and you may want to buy wines that can be cellared for leisurely enjoyment. Knowing how to pick a wine to age requires you to become familiar with wine characteristics and not the initial taste of a young wine. What this means is that a wine that needs to be aged for 10 years, may not taste very good when it has only spent 3 years in the bottle, likewise a wine that is intended to be drunk when it is young may not taste any better after 10 years and may in fact lose color, body and flavor.
While you will always want to buy wine styles and varietals that suit your wine palate, it is important to know what characteristics a wine needs in order to be able to bottle age in a cellar. There are 4 main characteristics that can help you determine if a wine can stand the test of cellaring and they are:
- Alcohol content
- Residual sugar
- Tannins and acidity
These characteristics can be overwhelming or taste out of balance in a young wine, which is an indicator that time will let these characteristics develop and mature with age. When a wine ages, it undergoes hydrolysis, which happens when the acidity and ethanol alcohol break down the other compounds in the wine, creating new compounds and releasing volatiles. To understand how these characteristics affect the aging of wine and support each other, let’s look at each one.
Alcohol is a volatile compound and while added alcohol in a fortified wine helps preserve wine, in non-fortified wines the opposite is true. Generally speaking, in higher alcohol wines made to be drunk when they are young, the alcohol can acetify, making the wine taste sour like vinegar; this process is called acetification and the resulting wine is affected by what's called "vinegar taint" in the wine industry. The standard aged Bordeaux wines had an average alcohol content of 12.5%, which seems low compared to modern drinking wines. A good rule of thumb is to choose a non-fortified wine with an alcohol content of 13.5% or lower and to choose fortified wines with an alcohol content of 17-20%.
Residual sugar is the natural grape sugar that is left in the wine after fermentation. During fermentation the yeast convert the sugar into alcohol and CO2. The strain of yeast in the wine determine how much alcohol is in the wine by how much alcohol the yeast can tolerate. Typically, excess residual sugar will maintain the alcohol content and balance the acidity in the wine.
Acidity and PH
The PH level determines how dynamic interactions between the compounds will play out, while the acidity level of the wine affects the way a wine tastes at every age. Over time, wines can lose their acidity, becoming flat or flabby, so a wine with a higher initial acidity interacts more with the other compounds, and will become smooth rather than flabby.
Tannins in wine come from the skins, seeds and stems of the grape during maceration and initial fermentation and from oak if the wine is barrel aged. Tannins are a structural component of wine and have very high anti-oxidant properties, which helps preserve color, flavor and aroma in the wine. In the absence of tannins, like in aged, unoaked white wines, the balance of acidity and PH, alcohol and residual sugar create the environment for aging and development of compounds, flavors and aromas.
In addition to these fundamental characteristics of the wine, be sure to keep your wine away from direct light in a temperature and humidity controlled wine cellar or cooler for the best results.