Red, Red Wine ...

Red wine can vary in style from bright pink Rosés to dark burgundy blends. While white wines can be quite an artform of their own, undoubtedly red wines are headier, bolder and require more complex winemaking skills, and intense procedures.

As mentioned before on this site, you don't need to be a winemaker to appreciate red wines, however knowing something of the processes will help you identify some of the characters you might come across.

Traditional Vinification

This is the term used to describe the production method of most red wines. It refers simply to the fermentation of wine on skins. This is done to enable extraction of colour, and the infusion of phenolic compounds from the skins, stalks and seeds included in the must. The inclusion of these compounds and colour is the primary difference between red and white winemaking.

Go back to Winemaking Main Page to review the simple steps of winemaking, then come back here to read on.

With red wines, much of the complexity of the styles is determined by the handling of the fermentation and aging. Winemakers are highly skilled and trained either traditionally down generations, or through universites around the world, in making wines, and to truly appreciate their talents, you need to know a little about the techniques of vinification.

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Red Wine Grape Picking

Most red table wines, particularly those used for large-scale production, are mecanically harvested. Even in the traditional winemaking areas in Europe, modifications to vineyards and viticultural practices are enabling this efficient method of gathering grapes.

Finer reds, for example Beaujolais, or Rosés - where Carbonic Maceration is part of the production plan [read section below to understand CM], still require hand-picking. If you want whole bunches with minimal phenolic extraction, this is the way you have to go.

Often, sulphur dioxide is thrown on the grapes, particularly in warm regions to inhibit uncontrolled fermentation by wild yeasts before the fruit gets to the winery.

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Must Handling

There are many considerations a winemaker has to take into account when monitoring the fermentation process of red wines. Some of the more important ones:

Destem or not destem?

Inclusion of stems in the must adds flavour such as herbaceous characters in the wine. Sometimes a 'grassy' flavour character is desirable in some white wines, but in red wines it actually detracts from the fruity, berry flavours. The winemaker has to decide if he wants this or not in his reds. Stems also impart tannins into the wines, adding to the structure. This might be handy if there is little other tannin input opportunity in the production method being used.

But stems have other surprising impacts on the fermentation, that you probably haven't thought of. Stems absorb alcohol and skin pigment, adding water and potassium ions at the same time. Depending on your scientific knowledge, you may understand then that inclusion of stems in the must will slightly lower alcohol, acidity and colour in the resulting wines. If you didn't, then you know now!

Acid Adjustment

Grapes in warmer regions don't achieve high levels of acidity, and in order to keep balance in the wine, tartaric acid is adjusted to the must. But it's not just about sensory charactertistics. If you have read other pages on this site, you may remember that acidity is important to stabilise colour in the wine. Balanced pH is also necessary to inhibit "off" characters which can generate in the wine during fermentation.

In cooler regions, where the acidity may be too high, this is countered by the addition of calcium or potassium carbonate.

Cold Maceration

Musts can be cooled to control fermentation - otherwise alcohol levels can get too high without adequate time for leaching of colour pigment from the skins. This practice also produces better quality wine, enhancing colour and flavour.

Juice Enhancement

Chaptalisation refers to increasing the sugar levels in wines by addition of sugar to the must or even the wine itself. This practice usually happens in colder winemaking regions, where it is legal to do so. The laws in relation to chaptalisation vary from country to country - particularly in Europe. In Australia it is not permitted except during secondary fermentation of sparkling wines, or to flavoured 'wine coolers' and brandy. It is however legal in New Zealand.

To overcome any disadvantage of stem inclusion in a must already low in sugar, grape juice can be added [Australia] or sugar [where legal in other countries].

A French method of enhancing juice - particularly in making Burgundy [or Pinot Noir] is to 'run-off' juice. The process sees a portion of the juice 'bled' or run freely from the crushed grapes prior to fermentation. The remaining juice then has better colour, flavour and structure - obviously, as there's less of it coming in contact with skins.

The Italians have another method of enhancing juice. They dry the grapes on mats to reduce juice quantity. Called 'recioto', this process is popular in the north east of the country wth Veneto wines.

In hot, dry regions of Australia, a simplified form of recioto is practiced - probably by default on many occasions - by allowing the grapes to dehydrate on the vine before harvest.

Pasteurisation

Pasteurisation of red musts would be considered where grapes have been affected by bunch rots. A method of pasteurisation called 'termo-vinification' breaks down the permeability of grape skin cells - resulting in release of tannins, flavours and pigments from the skins into the juice.

This is an appropriate practice only for drink-early, soft red wine styles for casks. It accelerates aging and loses fruit characters in the wine - not to mention running up heating bills. The process requires the wine to be heated to around 70^oC via heat-exchange and held at that temperature for up to an hour.

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Fermentation

Red grapes have a lot more wild yeast population than white grapes. So, when it comes to red wine making, the winemaker uses a larger innoculum of their selected yeast to dominate the ferment. But this isn't the only major difference when making red wines.

Temperature

Red wine ferments run much warmer than whites. This is generally to enable easy extraction of the colours and phenolics from skins. Light-bodied, fruity reds will experience ferment at around 15-18^oC, whereas a heavy-bodied, complex wine will have been submitted to as high as 25-30^oC.

Cap Management

While the fermentation process is underway, the skins, seeds, pulp etc tend to float to the top and form a cap. This isn't good, as the juice needs to be kept in contact with the fermenting debris [which actually ferments at a higher rate than the juice] to extract colour and develop structure. As the cap ferments at a higher rate, it is also up to 10^oC warmer than the juice.

To fix this, the cap needs to be kept completely in contact with as much of the juice as possible, and this is often done using anything from brooms which plunge the cap down into the juice at regular intervals during the ferment to sophisticated rotary fermenters, which provides the maximum exposure opportunity.

Not all oak comes from barrels!

Happily this 'cheat' is generally reserved for commercial quality wines that are mass produced. Oak barrels aren't cheap, so there's alternatives to provide oak influence in red wines. Artificial infusion is achieved with the use of bags of oak chips which are suspended into the wine.

Well, it beats powdered tannins, surely ... and yes, these are used too.

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Post Fermentation Processes

What about MLF?

You hear this term a lot. MLF is an acronym for Malo-Lactic Fermentation. This is a microbiological process that can occur after primary fermentation to convert L-malic acid to lactic acid. Sometimes MLF occurs naturally, but if not, it can be jump-started with a bacteria starter culture.

The main benefit is the conversion of stronger, sharper malic acid to weaker, softer lactic acid. This also means an overall deacidification effect.

Warmer weather increases the malic acid level in grapes, which results in hazy wines that release tiny gas bubbles. But overally acidity in warm weather grapes is low to start with, so MLF can actually have a detrimental affect by turning the wine flat and insipid with minimal protection against spoilage organisms.

On the plus side again, though, MLF produces some complexity to wines by imparting a buttery or butterscotch flavour.

Time on Oak

Red wines that are stored in stainless vats or in large, old barrels tend to lack complexity [granted, they do retain fresh fruitiness].

Maturation in smaller oak barrels [ranging from 80 to 500 litres] can have colour, flavour and tannin-softening effects on the red wine. Sometimes fermentation continues on in the barrels prior to maturation stage.

A full-bodied red wine can spend anywhere from 6 to 24 months on oak.

For further information on oak barrels see the Winemaking Main Page.

Final Polish

Fining, stabilisation and clarification of red wine can happen during the aging process.

Fining reduces astringency and bitterness by removing excess tannins. Egg whites and gelatin are common fining agents. The proteins in these agents bind with tannins, which then drop to the bottom of the vessel containing the wine.

Cold stabilisation can occur naturally in barrels over winter, and helps reduce haze in wine. This is more important for whites than it is for reds, though. In fact it is believed to have a detrimental effect on flavour. Haze is pretty hard to notice in dark red wines anyway. Occasionally you will notice it in the bottle after the wine has been drunk.

Clarification can be done via filtration or by settling the wine and racking it off any sediment which sinks to the bottom.

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Rosés are Red

The lightest of the red wines is Rosé. These relatively delicate red wines vary in sweetness and body depending on the grape varietal used and the production methods.

To produce Rosés with fresh fruity characters, the grapes need to be destemmed from the outset to reduce exposure to phenolics. Pressing is usually gentle in good quality production to again minimise phenolics and bitterness from grape seeds.

Rosés as juice experience a short fermentation time on skins at moderate temperatures to extract enough colour, but not tannins. Afterward the juice is often run-off rather than aggressively seperated from the skins.

Carbonic Maceration is used to make premium rosés - whole grape bunches are stored after picking in containers from which all oxygen is extracted and dry ice is placed in to create an anaerobic atmosphere. Sometimes these containers [or bags] are left out in the vineyard in the sun for 1 to 3 weeks for this part of the process. Being deprived of oxygen kicks off an enzymatic fermentation activity in the intact berries. There is no introduced yeast cells causing this fermentation. Rosés made in this way exhibit bubble-gum or lolly flavours. Yum. Obviously this can't be done with mechanically harvested grapes.

Carbonic Maceration is a technique also used to make Beaujolais in France.

The cheats' way to make Rosés is to colour-strip red wines. This makes pretty poor quality wine, which is often then turned into sparkling wine base.

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Sparkling Reds

Sparkling red wines are made pretty much the same as still red wines, with emphasis on a tannin profile that delivers softness and avoids bitterness.

Following standard sparkling techniques, the still red base wines go though tiraging and secondary fermentation either in tank or in bottle.

After tiraging, secondary fermentation can last anywhere from 1 to 10 years whilst the wine builds up in intensity, and develops a creamy, smooth and velvety mouthfeel.

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Further Reading: