How to Mature Home Made Wine

We often hear that wine has to be aged to achieve its full potential. This is true up to a point, but it's not the whole story. Most wine will improve if kept (in the right conditions) for two or three months, but beyond that, unless the wine has been designed for aging, it is more likely to deteriorate than improve.

Here are two good reasons for attempting to mature your own wine:

• You've mastered vin ordinaire production and are looking to expand your hobby with a new challenge.
• You've acquired a taste for well-aged commercial wines and it's costing you an arm and a leg.

And two good reasons not to get into the aging game:

• You've made a foul brew and you hope stashing it away might salvage it.
• You're impatient and/or careless by nature - this is not for you!

In other words, maturing wine is for mature winemakers! Those who understand the principles and practice and can reliably turn out a steady supply of good sound table wine. So, if you're still with me, let's look first at the theory of wine-aging, before getting into techniques.

When fermentation is complete, the young wine is not bottled immediately but is transferred to the aging vessel (leaving the yeast sediment behind) for the aging process to begin. Throughout the aging period, several slow processes continue in parallel. Among these are:

Clarification

Though a young wine can fall acceptably clear within a few weeks, it takes time to obtain the true 'polished' clarity of a well aged wine. Over time, aided by stillness and constant temperature, tiny haze particles gradually coagulate and sink to the bottom, usually without recourse to finings or filtration.

Stabilisation

This is not a single process but a combination of many beneficial trends. Dissolved fermentation gases (mainly carbon dioxide) are slowly released, so that the wine will not produce bubbles when poured, or 'prickle' on the tongue. Generally, the imbalance between quickly produced fermentation products evens out with time, through slow equilibium reactions.

Oxidation

Some oxidation is inevitable and even desirable, but it must not be allowed to proceed too quickly. Fermenting wines are protected by dissolved and expelled carbon dioxide, but a maturing wine is not. Oxidation causes loss of colour and a flatness of taste and aroma. Judicious use of Sulphur Dioxide (SO₂) as an anti-oxidant keeps oxidation down to a controlled level. SO₂ correctly used is perfectly safe.

Refinement

A young wine will often smell and taste fruity and alcoholic. This can be very pleasant in itself, but lacks 'refinement'. In other words, it smells simple because it is simple. However, with time, the 'in your face' fruitiness fades, to be replaced by a far more complex and subtle combination of smells and tastes, due to the production of even trace quantities of different organic acids, esters, aldehydes etc. In fact, over-production of any single organic compound usually constitutes spoilage, but, ideally balanced, they contribute to that much mocked term, bouquet.

Softening (tannins)

A pulp fermented red wine will often have a high tannin content. Tannins are extracted (by alcohol) from the pips and skins during the pulp stage. Their effect is to make a wine astringent, harsh and even undrinkable. But they are useful during aging because they act as retardants on oxidation and various other reactions, Thus they make the aging proceed more slowly, resulting in greater subtlety. Gradually the tannin content reduces and the wine 'softens'. In Bordeaux, for example, residual tannin is one of the biggest factors in releasing a wine to market.

With a few exceptions, the modern tendency is to drink white wines young and mainly age the reds. In part, this is market driven. Commercial aging is expensive as it ties up storage space for no revenue. But fashion and the market go hand in hand, and most people's expectation is very much for light fresh whites and heavier reds.

I would advise against aging whites (beyond about three months) for two main reasons:

• In the relatively small quantities produced by amateurs, it is much harder to control oxidation, and whites are less forgiving than reds in this respect.
• Most of the white wine we produce is not of a type that has much to gain from long aging and in fact is likely to suffer from the process.

Better to practice the techniques with reds, at least for the first few batches.

So, what red wines age well? Here are a few pointers:

• The wine should have been fermented on the pulp for 2 to 4 days
• It should then have been allowed to ferment to dryness

• It should be strongly coloured and may be strongly flavoured
• The alcoholic strength should be between 12 and 14 percent ABV (and within this range it's better to err on the high side)
• The total acidity will typically be 3.5 to 4 ppt

• It should have medium to high tannin (and may be quite harsh)
• It should be sound with no off smells or flavours
• The minimum quantity worth aging is 5 litres or 1 gallon. But you can get better results with larger quantities.

Traditionally, commercial wine is aged in oak casks and for the ultimate quality this is still the best way. But it may not be best for the amateur. Here's why:

• Quality oak casks are expensive and difficult to get hold of
• They need special maintenance and sterilisation techniques
• In small casks, too much of the wine (proportionally) is in contact with the wood. This will result in too much oak tannin extraction, giving a bitterness and over-oaked flavour (a little is good but not too much)
• In small casks, oxidation usually progresses too quickly.
• Five gallons should be considered the absolute minimum cask size

Glass has always been the amateur's preferred material. It has many advantages over oak: it is easy to sterilise and completely airtight, making it a much safer bet against spoilage and oxidation. The main drawbacks are its weight and breakability. For small quantities (below 5 gallons, glass is the obvious choice.

Food Quality Plastics are appealing for lightness, screwtop closures (no need for corks) and being unbreakable. But some plastics will impart a smell to the wine. I have had some success with drinking water containers. I use nothing else for fermenting, and have recently successfully matured wine in some. But alcohol and water have very different solvent properties, and some plastics that are perfect for water might partially break down and impart chemicals into an alcoholic solution over an extended period. As there are so many different plastics, it's impossible to make a firm recommendation.

The ideal environment for maturing wine is still the underground cellar. Here is what a maturing wine requires:

• Strictly no sunlight
• Moderate humidity

• An even, steady temperature ideally around 13^oC or 55^oF
• No vibration
• Good ventilation
• No strong or musty smells

In other words, an underground cellar! If you're not so lucky, try to provide as much of the list as possible. In typical modern accommodation, the hardest condition to provide is the steady cool temperature. I suggest preparing your space for maturing wine and placing a maximum/minimum thermometer in it for a few weeks to see what's really going on. Over temperature accelerates all processes, especially oxidation.

I did begin by saying wine-aging isn't for the impatient - thank you for reading this far! Here's what to do. I'm going to assume that you have a wine that fits the bill and has reached the end of its fermentation.

1. Add sulphite to the finished wine at the rate of one Campden Tablet per gallon and place it in the fridge (if possible).
2. After two days, sterilise the maturing container with a strong sulphite solution, then rinse it out with boiled water
3. Transfer the wine into the sterilised vessel. Either pour carefully using a large funnel, or syphon it, leaving behind the fermentation sediment.

4. It doesn't matter if a little sediment does come across.
5. The bubbling is dissolved CO₂ coming out of solution. It is normal and doesn't mean the wine is still fermenting.
6. Make sure the vessel is full to the neck or just below. If you have to top it up, use a little cool boiled water - not fruit juice or sugar syrup!
7. Seal the vessel (exactly how depends if its glass or plastic, of course!)
8. Place it where it is to remain for the next several months,
9. For the first week or two, you should check regularly for residual fermentation - simply open and close the cap to release gas.
10. After that, do nothing much for a long time. You can guage clarity by shining a torch through the sealed vessel, but don't keep opening it up to smell it. Have faith!

11. After about 6 months, it's decision time, and here are the options:

• Mature it for another 3 to 6 months. If you plan to do this, sulphite it again, at the same rate, and syphon it carefully to a new sterilised vessel. This helps the stabilisation process.
• Bottle it 'casually' for immediate drinking. If you want to use it within weeks, simply transfer it into empty drinking water bottles and use as required.
• Bottle it 'seriously' for laying down. Only consider this if it seems really promising but still a little immature. Serious bottling means glass wine bottles, real corks, labels, racking, etc. and will be the subject of another hub!