Aim for Age

Wine is one of the few food products that has the potential to get better with age. Not all wines improve with age, but those that do are highly-prized. Wine scientists are just discovering what makes some wines age gracefully and others decline over time. Find out what you can do to increase the odds of making an ageworthy wine.

Of all the things that make wine wonderful, nothing is more alluring than the potential for aging. No other food product enjoys the same extended trajectory as wine; no matter how scrumptious your osso buco or cheesecake is today, it won’t hold up for 20 years, let alone get better.

Ageability is the property of wine that makes auction prices skyrocket and the reputations of certain wineries soar. Not every wine is made to age, and not every wine that’s supposed to age well actually does. But it’s enough of a status magnet that every serious home winemaker should try to make wines that age, right? Maybe.

Before declaring your next batch of X is going be enjoyed by your grandchildren, you need to decide a bunch of things: that you really like the taste of old wines; that you have a place to store them so they can develop in peace; that your winemaking is good enough to guarantee long-term stability in the bottle; and that you have the patience to wait a decade before drinking something that took all that work. If all those conditions are met, here are a few things you should know and can do in your garage to make wines worth keeping around.

The Science of Aging

Over the sweep of winemaking and wine drinking history, many factors have been cited as keys to the ability of some wines to age, and most of these continue to have some currency, at least in the popular discussion of ageability. Sugar must have something to do with the amazing life expectancy of sweet-style German Rieslings; and the development of those same wines also suggests a life-affirming role for acidity. High alcohol, especially in the form of fortified wines, has a long history as a means to ensure stability in wines long enough for their hidden charms to surface.

But wine science in the past three or four decades has zeroed in on the role of phenolic composition as the critical element in longevity, at least for red wines. The key players here are the complex polymeric combinations of anthocyanins and tannins that develop — maybe — in the first few years of wine aging and play a critical anti-oxidant role for the years after that. It’s not exactly that pigmented polymers prevent oxidation; rather, they promote and are in part a result of “good” oxidation, combining with oxygen in a way that controls aging, rather than encouraging deterioration.

Polymerized tannins also contribute to the evolution of mouthfeel, from firmer and more astringent to softer and rounder. Even though bigger, long-chain tannins are generally more astringent than shorter forms, the polymeric phenols somehow find a way to become less rude. Leading phenolics researchers like Andy Waterhouse of the University of California  at  Davis and Jim Kennedy of Oregon State University admit they don’t yet know exactly how this happens.

It would be wonderful if we could find a magic number, a measure of phenolic content, that would predict life expectancy at bottling. We don’t have that number, but Waterhouse and Kennedy agree that a total phenolics measurement of 2 1⁄2 grams per liter (0.33 oz./gallon) or higher would likely put a red wine in the ballpark as a prospective ager. But as we’ll see in a minute, there’s a lot more to it.

Acidity and its counterpart, pH, clearly also play a role in ageability. Much of the benefit of relatively high acidity and relatively low pH is indirect: by creating a less microbe-friendly environment, these factors make it less likely that a wine will go bad before it gets really good. For white wines, which have low phenolic content because they are not fermented on the skins, acidity and pH are critical.

That would help explain why some high-acid Rieslings live forever, and why higher-acid Chardonnays from Burgundy may age better than lower-acid Chardonnays from California. On the other hand, experience around the world suggests that Sémillon tends to age better than its common higher-acid blending mate, Sauvignon Blanc; and similarly,  relatively low-acid, high-pH Marsanne ages better than high-acid, low-pH Roussanne among Rhône whites.

Go figure. When I asked Jim Kennedy what made whites age, his first response was, “Beats me” — though he went on to say that acidity and pH clearly had something to do with it. Veteran Napa winemaker Mitch Cosentino — who has worked with just about every grape on earth over the years — says, “Must be something in the DNA.”

Ask a winemaker what makes wines age well, and you won’t hear much talk of phenolics: you’ll hear ”balance.” This is a slippery term, but it generally means a wine in which no single element sticks out. The underlying theory, largely true, is that if a wine is out of balance now, it will still be out of balance in ten years.

Recently, the focus of the “balance” discussion in California has been on high-alcohol wines, with a chorus of detractors claiming or suspecting that this style of wine, with alcohol at 15% or even higher, instead of a classic 12.5–13.5%, will just fall apart with a few years in the bottle. Davis’ Andy Waterhouse isn’t so sure. Alcohol, by itself, is a preservative — just think about fortified wines like port and sherry. “The Bordeaux standard that we’re used to,” he says, “had moderate alcohol and low pH. What the current ones will taste like we can only speculate about, but we can guarantee they will be different. If we hold to that historical standard, they won’t be as ‘good’ — but a lot of people may still enjoy them.”

Chemical Evolution

There’s a little more to the science part. Knowing — at least sort of knowing — what helps preserve a wine isn’t the same as knowing how it will taste ten or fifteen years down the road. It is quite possible to make a boring wine and have it still boring a decade later, perfectly preserved. It’s also possible to have a promising wine get less and less interesting over time. Both of these things have happened more times than winemakers would like to count. We don’t like old wines because they’re old; we like them because they smell and taste good.

There is more to an ageworthy wine than just the proper chemical balance. The vast majority of jug wines and supermarket standards have perfectly good numbers. But nobody expects them to age, and sure enough, they won’t. There has to be something else in the bottle, some stuffing, some great fruit, some something that’s hard to quantify but worth preserving. It’s one of those things you know when you taste it, but can’t reduce to a formula.

Sue Ebeler, flavor chemist at UC Davis, says we aren’t at the point where we can predict tomorrow’s sensory profiles from today’s chemical composition — there are too many complex interactions that affect perceptions. A lot of the things we like in older wines develop from precursor compounds in the young wine — except that these precursors may not have any volatile, sensory properties that we can pick up on.

So, there’s a definite element of luck in how a particular wine ages, and that can help you set the expectations for your own winemaking. If you pay attention to detail, you can almost always make a perfectly drinkable wine at home that can be enjoyed while it’s young. Aging wines is much more of a crapshoot — but if you like older wines, it’s worth a try.

Getting Prepared

There are a lot of things you can do to increase the odds of success. The first thing to do is drink a lot of older wines, make sure you like them, learn what to look for and hone your palate. Older wines don’t smell and taste like young ones: that’s the point of aging them. Try some five-year-old Zinfandels and ten-year-old Cabernets, some Rieslings from the last millennium, and the oldest Burgundies you can beg, borrow or steal. By surveying the field, you’ll learn which grapes you like in their more mature form: you may, for example, love the tobacco and cedar in old Bordeaux and just hate that petrol thing in old Riesling; or vice versa.

For your winemaking, work with varieties that have a known aging potential. Bordeaux Reds are good bets, as are Syrah, Zinfandel and Pinot Noir. All the aromatic whites are eminently ageable. Vinifera varieties are probably more serviceable than hybrids for this project. The best strategy for a first effort, I think, is to pick a grape you already know you like to drink when it’s getting on in years.

And for that elusive something the grapes need to have, that DNA Mitch Cosentino jokes about, know your grape source — fruit you’ve worked with before, or a vineyard whose wines you’ve tasted made by somebody else.

Winemaking Essentials

For red wines, getting a sufficient extraction of phenolics — tannin and color — during the fermentation is the biggest single requirement. Since you probably won’t be able to run a handy home test for total phenolics, you won’t know if your wine is near the 2 1⁄2 grams per liter (0.33 oz./gallon) threshold. Instead you’ll have to pass judgment by looking at and tasting the wine carefully as it ages.

It might seem that more is always better when it comes to extractions, but that isn’t true. Pinot Noir will never yield the volumes of tannin and anthocyanin that some other reds give, and trying to beat those stingy grapes into submission will backfire. Cabernet Sauvignon, with smaller berries and a high skin-to-juice ratio, can easily offer up too much tannin, creating a harsh, astringent wine that may require fining later on. Good, solid extraction from a well-managed fermentation, yes; swinging for the fences, probably not.

The key variable in a successful fermentation is temperature control — a warm enough temperature to get good extraction for reds, or cool enough to preserve aromatic esters and fruitiness in white wines.

Your local winemaking supply shop will be glad to sell you all kinds of enzymes and elixirs designed to extract more color or tannin or aroma compounds, and some of them actually do what they claim to do. Ditto specialized yeast strains that can accentuate one or another aspect of extraction or promote a certain kind or fruit expression. Feel free to make use of these tools, but just remember that the quality of the grapes is the most important element, followed by fermentation temperature management. The rest is relatively small potatoes.

Good commercial winemakers taste their wines throughout fermentation, looking for good and bad developments and evolving balances. For less-practiced home winemakers, starting to taste at least at the time of pressing is critical. By that point, the free run wine should be a good clue about the flavor profile of the wine and any flaws that need correcting, and the press wine is an indicator of whether the tannic backbone is too much, too little or just about right. The sooner you get a handle on the wine’s depth and structure, the sooner you can start steering it toward a final style.

As the wine spends months in your cellar, garage or tool shed before bottling, you may not be doing much to it, but you need to remain in control of it. Many of the fine wines of the world are made under what seem like insane conditions — anxiety-producing sanitation regimes, hostile temperatures, ancient equipment. But don’t try this at home: conservative protocols are a much more rational approach. This starts with being scrupulous about sulfur dioxide additions and levels. The goal is to have your wine taste clean at bottling and stay this way. There are plenty of “bugs” — starting with Brettanomyces — that can take their sweet time and bloom later on in the bottle, unless you get rid of them first. Additions of SO2 in whatever form need to be calibrated to the wine’s pH. (Here is a calculator that allows you to calculate SO2 additions, based on the wine’s volume and pH.)

Accurate testing for pH as well as free and total SO2 is essential. Timing also matters: adding a big dose of SO2 too early can impede a malolactic fermentation; too late can let your wine be a microbial playground for far too long.

Testing for complete dryness and for completion of the malolactic fermentation — or for the prevention of it for most whites — is also essential. It’s not just us amateurs who screw this up. Recently I opened a lovely looking 1999 Ridge Zinfandel, a bottle I had stored carefully for seven years, from a respected winery that knows its stuff. To my surprise, it showed clear evidence of the Home Winemaker’s Curse — the unintended completion of the malolactic in the bottle, complete with vegetal aromas and a spritz that shouldn’t have been there. Don’t let this happen to you: test before you bottle.

Oxygen management is another important technique that has implications for aging. Wines need oxygen to get through fermentation; wines in barrel benefit from slow, steady oxygen infiltration to help them get rounder and more integrated. A good dose of oxygen in a splash racking may be just the thing to get rid of a mild case of hydrogen sulfide stink from a slightly sluggish fermentation. On the other hand, you don’t want to bottle your wine with a ton of oxygen in it — from sloppy racking or bottling practices, or a badly done filtration. That excess oxygen may not have any impact on the wine you drink the day of bottling, but it can erode the wine over time.

Just as you aren’t likely to have a measure of the total phenolics, you probably don’t have a meter for reading dissolved oxygen in your bottling line, either. All you can do is be careful at every step of the way, giving the wine oxygen when it needs it, keeping oxygen at bay when it doesn’t.

Storing and Drinking

Once the wine is bottled, the waiting begins. It is not as easy a period as it sounds, because once again, you have to pay attention.

The starting point is ensuring good storage conditions. You wouldn’t store your prize ’61 Mouton next to the heater, or out in the garage with its seasonal mood swings, and you shouldn’t treat your own wine any differently. The recipe for proper wine storage is simple and familiar: steady temperature, preferably at or below 60 ºF (16 °C); reasonably high humidity (around 75%) to combat evaporation; little or no light; and freedom from vibration. Moderate and consistent temperature is the heart of the matter: high heat, or constant temperature spikes and drop-offs, will dramatically shorten your wine’s life expectancy and change its aging trajectory, not for the better.

And while you are waiting, taste the wine periodically. Just because you think you’ve got a ten-year wine, don’t wait ten years to try it. Trying a bottle every three months for the first year and every six months thereafter allows you to spot any negative trends, find the “sweet spot” when the wine is at its best, and learn a lot about how wine develops. There is no precise scientific checklist for how a wine will age, and no substitute for checking it out periodically. Even with wines that may not seem to have much aging potential, it’s a good idea to tuck away a few bottles and try them over time — you might find a pleasant surprise.

Chances are your home bottling is finished with natural cork, in one form or another; screwcap technology is awfully expensive, and synthetic corks sometimes disagree with hand corking equipment. The good news here is that natural corks generally offer the best oxygen transmission rate for encouraging aging.

The bad news, of course, is the possibility of cork taint (from TCA) and a greater chance of unevenness. All of which implies that for wine you want to lay down for a while, spend the extra bucks to get the best corks you can find; they might cost you an extra 50 cents a bottle, but they save you a lot of future unpleasantness.

Time for Drinking

Every bottle, as we like to say in the wine business, is a little different — that’s the fun of it. But as a general guide, apply what you know and what you like about similar commercial wines, and shorten the estimated span a little bit, to compensate for the limitations in sanitation, oxygen control, and storage conditions that home winemakers generally have to contend with. Serious reds carefully done on a small, home scale should be good for 5–10 years. A lot of whites aimed at early drinking actually benefit from a year or two in the bottle, making their time of consumption more like the commercial wines you routinely drink. Homemade aromatic whites are especially likely to be more fun in three to five years.

Again, drink the wines when they taste good to you. The point of aging is to increase enjoyment. If you like young wines, drink ‘em young. If your wine tastes right at three, don’t hold it back till it’s ten.

And if it’s really good at ten, pat yourself on the back.