What makes a wine have the ability to age? Jules Renard is quoted as “It’s not how old you are, it’s how you are old.” The Earth continues to revolve around the sun, so we are all growing older, but it is fairly obvious that some of us age better than others. That statement is as true with wine as with a human being. So what is the magic that some of us hold that allows us to age more gracefully than others? Why do some wines gain a resounding yea rather than a sorrowful nay?
The Spine is Crucial
Just as we need a spinal column to allow us to stand up, a wine needs its backbone. Our stability comes from the vertebral column. Its function is to attach to muscles and protect our spinal cord. It is the central axis of the skeleton and crucial to our longevity. A wine’s central axis is not made of bone and cartilage; instead, its support system comes from its pH, acidity, and tannin level.
In reality, the ability of a wine to age comes down to understanding the science of what is going on inside the bottle as it lays down over time. There are external factors that can come into play. Exposure to sunlight, vibration, and extreme temperature can wreak havoc on wine and turn it from a masterpiece into a catastrophe. Additionally, the glass and closure play an important role in quality control. But these factors are equivalent to our external risk factors. For example, continuous exposure to the sun can hinder our life expectancy. Extrinsic influences impact the capability to reach the potential but do not impact what that potential could have been. For this reason, we will eliminate these extraneous concerns and assume proper storage and oxygen ingress of the closure and focus on the natural potential of a wine’s ability to age.
It’s What’s Inside That Matters
The liquid itself determines if it is a “drink now” or “drink later” wine and potential age-ability begins in the vineyard. The fruit itself must have proper analytics to produce a wine with the promise of aging. The most critical component of the wine’s ability to age is its structure. The structure is determined by the wine’s pH, acidity, and tannin level.
Certain grapes, simply by their genetics, have the potential to age better than others (just like us humans). Genetically speaking, some grapes have thicker skins than others. Cabernet Sauvignon, Merlot, Syrah, and Petite Sirah are examples of thick-skinned grapes, while Pinot Noir, Grenache, and Gamay are examples of thin-skinned grapes. Close your eyes and think about sipping a glass of each of these varieties, and you can begin to see the impact the skin has on the mouthfeel of the wine.
Furthermore, individual grape varieties have a natural affinity for increased acidity levels. Riesling and Sauvignon Blanc tend to have a higher acidity, while Chardonnay and Viognier typically have lower acid levels. There is an inverse relationship between acidity and pH. The higher the acidity in a wine, the lower the pH.
Acidity and pH
Oxidation is the aging process of wine. As the wine ages, more oxygen comes into contact with the wine, and the oxygen begins to change its chemical makeup. This process occurs faster in high pH/low acid wines. Therefore, a high acid wine has the aptitude to age longer.
Microbiologically speaking, a higher pH level provides a friendlier environment for microbial growth leading to spoilage. Once again, lowering the prospective length of aging.
Stable wine averages between 3.2 and 3.6 pH. Winemakers can correct unstable pH at the winery by adding sulfur dioxide. But if a wine’s pH is too high, the addition of sulfur dioxide will affect the flavor of the wine and exceed legal limits. There needs to be a balance between the acidity and the pH in order to provide the solidity to age.
Tannins are a defense mechanism for the plant. Their job is to provide a bitter taste so that animals don’t enjoy eating them and choose to move on. When an animal’s saliva, filled with protein, comes in contact with the tannin, the protein is sucked out of the saliva, leaving an unpleasant dry mouth. However, humans have decided this is a positive, mostly because we can add a steak or other fatty food to balance the drying effect.
The largest percentage of tannins (polyphenols) are found within the grape skins. Seeds and stems add to the tannin levels in the wine but on a smaller scale. This is why whole cluster fermentation will provide additional structure to a wine vs. de-stemming the same bunch. And tannins can also be added to the wine. Remember, polyphenols are found in the “wood” of the grapes, so, logically, fermenting and/or aging wine in wood adds tannins to the wine. Although a different version of polyphenols is found in the grape itself, oak barrels provide additional structure to a wine. Therefore, wines aged in oak barrels tend to be able to age longer.
The longer the juice remains in contact with the source of tannins, the more tannin it will absorb. In other words, prolonged contact with the skins and oak will provide higher tannin levels. A small barrel will provide more contact surface area to the total volume of wine. A larger barrel has a lower ratio of exposed barrel to wine. Only the juice in contact with the wood will absorb the polyphenols, so less contact means lower tannin levels.
There is a direct relationship between the amount of tannin and the propensity to age (there are white wines that are quite capable of aging thanks to the acidity, pH, and alcohol). But simply speaking, the more tannins, the longer the wine can age.
Tannins begin to “break down” as the wine ages, although the term breaking down is a misnomer. Breaking down leads to the wrong impression. Tannins, when young, are small molecules that are suspended in the wine. As time passes, the tannin molecules find each other and bind together, making them larger. Eventually, they become so large that they can no longer remain suspended in the liquid and fall out. As this happens, the wine becomes less tannic, and the mouthfeel becomes softer.
It’s a Balancing Act
Aging wine is like walking a tightrope. You need balance on the rope. Grapes, just like humans, rely on their intrinsic genetics that makes each person (or grape) unique from the others to determine if a finished wine has the potential to age well. So, when you are trying to decide if your favorite bottle of wine has the potential to lay down, consider its tannin level, pH, and acidity levels before you conclude yea or nay.
Feature Photo: ©Dayvison de Oliveira