Certain wines can improve with extended storage time, but you’ll find that there are a lot of incomplete ideas and misconceptions about wine ageing. What really happens to the wine in the carboy, barrel and bottle, and the role of sulphite and storage conditions, is often misunderstood. With kit wines in particular, the most common question people ask is, ‘How long will my wine last once I bottle it?’
In fact, kit wine will age similarly and as well as most wines made from grapes. The most important factor, other than the integrity of the wine itself in the bottle, is how the bottle is stored. If you keep a decent wine in a cave at a temperature of 10ºC/52ºF, with 60-80% humidity and zero light or vibration, and seal it with a quality cork and never move or disturb it, it will last a couple of decades without spoiling. However, inappropriate temperature, vibration, low humidity and change or variance in these conditions will affect your wine negatively.
Making Sure Your Kit Wine is Ready
The first stage in the ageing process is seeing to it that your wine is in the right state as it goes into storage. Clearing should be finished, and the wine should be stable in the bottle, carboy or barrel. If you do intend to age your kit wine, make sure it has between 35 and 50 parts per million (PPM) of free sulphur dioxide (SO2 or FSO2) when you’re ready to bottle it. FSO2 decreases over time and becomes ‘bound’ SO2 that is no longer able to protect the wine from oxidation or bacterial spoilage.
Some kits already contain adequate sulphite powder in their additive packs to ensure the 35-50 PPM level, while others have a more conservative amount. But in kits that have a lower level, you’ll always find a note in the instructions at the bottling stage, which reads something like, ‘If you intend to age your kit more than six months, please add an extra one-quarter teaspoon of metabisulphite powder to the wine before bottling.’
This of course raises the question of why, if 35–50 PPM is the right level, that extra sulphite isn’t just included in the package? We find that in general, people who make kits drink them fairly quickly. And with the advent of ‘wine-on-premise’ operations (shops where you can make your wine on-site and take it home after bottling), manufacturers began to see the rise of ‘trunk-ageing.’ That is, if you caught an on-premise winemaker loading his cases into the trunk of his car and asked how long he intended to age his wine, the answer might well be, ‘about three miles.’
In order to leave these quick-consumers a choice about the sulphite levels in their wine, some manufacturers left it low: you can always add more later, but you can’t get it out once it’s in the wine. Automatically including it would have added to the cost of the kit, and would also have resulted in the wastage of vast amounts of sulphite, as people who intended to drink their wine quickly simply threw the extra packets away.
If you’re in doubt about your own kit sulphite levels, either follow the manufacturer’s instructions or get a sulphite-testing kit and check your levels. Remember that nobody has ever spoiled their wine by doing too much testing and checking.
Bulk or bottle?
People often suggest that ageing in bulk, in the carboy, will produce better wine. Unfortunately, that isn’t actually correct. Once the wine is completely clear and stable, carboys don’t present any advantage over bottles, for medium-term storage. There is no particular chemical process that is aided by storing it in a larger volume.
Remember that even major wineries work to get their wines stable and ready, and then as soon as they are, they put them into bottles to finish ageing. For these wineries, there is simply no debate: it’s bottles rather than bulk, even though bulk potentially could be less expensive for them. In fact, the entire concept of ageing wine only came about in the first place, in the 1600’s, after the adoption of bottles and corks for wine storage.
However, there are two small factors that might favour bulk-ageing in certain circumstances. First of all, if your ageing/cellaring area goes through a lot of temperature fluctuation, then the larger bulk of a 23-litre/6-US gallon carboy will provide more thermal mass to ride out the temperature shifts, preventing sudden thermal shocks to the wine.
Secondly, if your wine is resting quietly in a nicely topped-up carboy, there’s no way to sneak a bottle to see if it’s ready. This premature sneaking can be a challenge to wine connoisseurs as well as to home winemakers. Some winemakers go so far as to store their best bottles at a considerable distance from their own homes, requiring a lot of effort to get to. After all, it’s very tempting on a relaxed Friday evening, after dinner, to get the sudden notion of digging into the cellar to try out your treasures.
If this temptation is likely to be simply too much for you, you may indeed need to resort to a carboy to restrain yourself. But in general, the best way to age your wine is in bottles.
Acceptable Cellaring Conditions in the Average Home
Temperature: Cool temperatures (about 12-17ºC or 55-65ºF) prevent heat damage (browning and oxidation), and keep the ageing process moving at a reasonable pace. Below this temperature range, wine will age very slowly, and above it, wine will age more rapidly. However, if you can’t store your wine in this range, don’t worry: anything below 22ºC/70ºF is reasonable for at least a year or two of ageing, if the humidity isn’t too low, and the temperature doesn’t fluctuate.
Consistent Temperature: Fluctuations in climate are actually much more damaging even than high temperatures. When wine alternately heats and cools, it expands and contracts inside the bottle. Because the bottle isn’t changing size, this means the wine will be pushing and pulling against the cork, and will either push it right out of the bottle, leak, or start drawing in oxygen — any of which will result in ruined wine in very short order. Your cellar should have less than a 5ºC/10ºF seasonal variation from summer to winter and less than a 1.5ºC/3ºF variation over the course of a day.
Humidity: Seventy percent humidity is ideal for most wines, but anything between 60–80% will suffice. Humidity over 80% can encourage mold, which will attack corks and ruin labels. Humidity under 60% will cause corks to dry, allowing evaporation and oxidation.
Darkness: Direct, bright light exposure (such as direct sunshine or glaring spotlights) can cause protein hazes and off aromas. Fortunately most household lighting isn’t that powerful. When given the choice, a darker area is always preferable to lighter.
Vibration: It may surprise you to learn that this is even a problem. But whether the vibration comes from appliances or a railroad junction outside the living room window, it can shake the wine so badly that some of the ageing processes don’t work, and the wine simply falls apart.
Odors: Most people don’t store paint or gasoline in their refrigerator, for the reason that the volatiles and solvents in petrochemicals, cleaning agents and household chemicals would rapidly taint food, rendering it inedible. The same thing could happen to your wine, if it becomes exposed to volatiles or other chemicals. The place in most houses where odorous chemicals are stored is the basement.
Tips for Battling Ageing Problems
Temperature fluctuations: Minimize the impact of temperature changes by keeping the wine up against a north-facing wall. Sunlight striking a foundation or the earth around it can cause a temperature flux, so steer clear of south-facing walls. You might also want to build an enclosure around your wine rack if it’s out in the open: this can help diminish convection currents, and increase thermal inertia. The enclosure doesn’t have to be anything fancy; you can create it from things as simple as Tyvek (the foam-board house insulating material), duct-tape and corner brackets.
Lack of humidity: In colder, drier climates like the north and the midwest, humidity can drop quite low, especially in winter. Too low and your corks will dry out, allowing oxidation and, potentially, leakage. Humidifiers sold for home use are not a good answer; they work too well, and can cause a build-up of mold and mildew in places like the basement, where air circulation is low. It makes more sense to set up a passive humidifier. Essentially this is a pan of water, a clean dishcloth and a cinderblock. Set the pan of water on top of the cinderblock in your wine cellar, drape the dishcloth half-in and half-out of the pan, and tuck the bottom end on top of the block. This will allow the towel to wick the moisture out of the pan and increase the evaporation into the air. The cinder block will hold any excess moisture and release it slowly, helping keep the humidity steady, even in a cellaring area as big as 10 feet by 10 feet.
Cellaring wine used to be a rich man’s game. Other than wine merchants storing stock for future sale, only the highly wealthy could afford to purchase age-worthy wines in large volumes, and then wait as the years passed to sample them as they approached their peak. The French used to say that you didn’t buy Bordeaux for yourself, you bought it for your children, while you drank the wine your father had bought.
Now home winemakers can also age their wine, simply, easily and much more cost-effectively than their predecessors. With wine kits, you can age a wide range of varietals and styles, from growing regions around the world. You may even feel a sense of poetry about it, following your wine down the years, watching it evolve, tasting the changes and appreciating the ebb and flow of time. However, at the same time, you shouldn’t wait too long, lest your wine become aged past its prime.