Our goal at Settembre Cellars is to produce age-worthy wines, and as such, I thought I'd share some thoughts on some of the factors that make a wine age-worthy. I'm often asked how long one should, or could, cellar our wines. A majority of the wines on the market are not cellared and are consumed relatively quickly after purchase (this is particularly true of the low priced manufactured wines). Of the wines sold, only a small percentage of the red wines (and even smaller percentage of the white wines) are in fact age-worthy. Vintage charts are often published that recommend wine aging potential for various varietals by region. Keep in mind, these are just guidelines for aging potential; viticulture and winemaking styles vary by winery and can affect a wines actual aging potential. Some wines are in-fact meant to be consumed young (Beaujolais nouveau for example). Being a relatively new winery (and wine region for that matter) we do not have a library decades old to establish a baseline and instead rely on comparisons to wines from other regions with similar styles to estimate our wines aging potential. We are cellaring a number of bottles from each vintage to evaluate age-ability of our wines and will in the future release our recommendations on whether you should consider drinking those special Settembre Cellars' bottles you're holding onto.
Wine is a living thing which is continually evolving. The mouthfeel, bouquet, and flavor of a wine evolve with time in the bottle. A completed wine often follows a trend where after being initially bottled it goes into shock. Afterwhich the wine often improves with time in bottle, sometimes passes through a 'dumb' phase, tends to plateau, and then falls off. In cellaring, the goal is to consume the wine on the plateau. The length of time for each of these phases varies from wine-to-wine and is dependent on the initial state of the fruit (region, microclimate, and viticulture techniques) and subsequently can be enhanced or lost through the specific winemaking techniques used. The ability of a wine to age is gauged on its ability to maintain or improve positive aromas and flavors while maintaining clarity and possessing microbial stability. An aged wine often demonstrates a loss of fruitiness and formation of new characteristics (transformation of aroma to bouquet) along with a decrease in astringency and loss of color.
Phenolics are the first key to age-ability. There are 6 classes of Phenolics, which in red wine are dominated by Tannins that are responsible for astringency (a sensation: think banana peal) and bitterness (think quinine – as in tonic water), followed by Anthocyanins which are responsible for color. Stilbenes, an antioxidant which includes Resverastrol, is also one of the Phenolic classes. Excessive tannins can make some wines less approachable in youth, though this is not necessarily a requirement for an age-worthy wine, rather a condition which may require a wine to be aged. Phenolics change with age (tannins polymerize to soften mouthfeel, color changes) and are influenced by oxygen. In wine, oxygen is the limiting reactant in a sea of oxidizable substrates, and with a catalyst induce reactions of wines constituents and subsequent reactions of these newly formed constituents. Phenolics react with oxygen and thus not only evolve but also scavenge to prevent the less desirable oxygen reactions from occurring (see the Blog on Oxygen) and give wine time to produce the interesting characteristics that come from bottle age.
A second key to age-ability, particularly in white wines which are lower in both tannins and anthocyanins, is acidity. White wines such as Chardonnay and Riesling, contrary to many folks' initial impression, can be built to last for decades. There are two measurements of acidity in wine. First is Titratable Acidity TA which measures the concentration of acids in a wine (those which can be reacted with a strong base). TA has the greatest impact on taste. If a wine is too low in TA the wine will be limp, or flabby. Too much acidity and a wine can be tart. In wines, acids combine with alcohol to form esters with new aromas. The second measure of acidity in wine is pH which is a measure of the strength of the acid (the number of free hydrogen ions). A very low pH can make a wine taste sour, however, at the pH typically encountered in wine it has little effect on taste. pH does however have a large impact on age-ability. Enologix (a company that databases wine measurements) suggested that wines with a pH of 3.6 ages an order of magnitude better than wines with a pH of 3.7. In cool climate viticulture it is typical to have a low pH and high TA (and thus perfect for our style of Chardonnay!), however, this can vary depending on the presence of potassium which acts as a buffer causing an increase in the pH.
A close follow on to pH is the free sulfite level (FSO2) in a wine. Sulfites are produced by the yeast during fermentation and often added by the winemaker to enhance microbial stability and prevent browning in white wines. The amount of FSO2 required to achieve a molecular SO2 (MSO2) level sufficient to provide microbial stability is strongly dependent upon a wine's pH. For example a wine with a pH of 3.6 requires a FSO2 level of 50 ppm to reach 0.8 ppm MSO2 while at a pH of 3.7 a FSO2 level of of just over 60 ppm is required to achieve the same level of MSO2. Lower sulfite levels may risk spoilage by Brettanomyces and other spoilage organisms. Although not critical from a health perspective (human pathogenic bacteria do not survive in wine – hence situations where wine really is safer than water) and a controlled amount of microbial activity can provide complexity to the wine, left unattended excessive microbial activity will likely evolve the wine to a state that is no longer enjoyable to consume. As such, sulfite free wines are typically not suited to age and should generally be consumed young (perhaps unless aided by very high alcohol levels and no residual sugar).
A final consideration with regards to microbial stability is substrate (or nutrients). A wine that has no residual sugar, is lacking nutrients (nitrogen), has limited oxygen, or in the case of Brettanomyces and Lactobacilli has had the required vitamin thiamin cleaved by SO2 may be unable to support microbial growth.
With age wines may also show visual signs of chemical instability (which are often only of visual concern). Often times in a red-wine that has not been cold-stabilized one may find potassium bitartrate crystals (often called wine diamonds which can look like shards of glass), polymerized phenolics may produce sediment or in concert with pigment lacquer the sides of the bottle. In whites, which are not fined with bentonite, a protein haze, may arise in the bottle and for fruit that was infected with Botrytis cinerea (noble rot – which depending on winemaking style may not be seen as nobility) may show enhanced Laccasse activity which may cause a wine to brown even after fermentation.
All of the evolutions discussed this far may be affected by storage conditions: temperature (the actual and fluctuations of), humidity, light, and effectiveness of closure (quantity and amount of oxygen see the Blog on Cork). To cellar a wine properly, one must store it properly. A repeated theme in winemaking and wine appreciation is understanding wine is a living, evolving, thing and a key is balance of constituents and condition. Settembre Cellars' wines are made to be approachable in youth for enjoyment today yet have the structure required by those, who like me, are fascinated to watch a wine evolve as the years pass.