White Wine Making

White wines are much more delicate than reds, so making white wines requires special handling techniques. Delicate or no, white wines can still be seperated into classes of light, medium or full-bodied wines.

White Wine Types & Styles

Light bodied, dry whites:

The Major varietals used for this style are Reisling, Gewurztraminer, Sylvaner, Mueller Thurgau, Pinot Gris, Muscat Gordo, Schönburger, Traminer.

The wines have low to moderate alcohol levels (9 to 12%v/v), high acidity, and Low pH. They exhibit floral aroma and flavour characters - derived from terpenes located in the skin and sometimes the juice.

There is preferably little winemaking influence on flavour and aroma [no malolactic fermentation 'buttery' character or oak flavour].

Classic examples: Riesling - premium regions = Rheingau & Mosel-Saar-Ruwer (Germany), Alsace (France), Eden and Clare Valleys, South Australia. Gewurztraminer from Alsace.

Full Bodied, Dry Whites

Major varietals used for this style are Chardonnay, Sauvignon Blanc, Semillon, Chenin Blanc, Marsanne, Verdelho, Muscadelle.

The wines have higher alcohol levels (12 to 14%v/v), lower acidity, and low pH. They often have buttery flavour characters from malo-lactic fermentation or derived from oak contact.

Classic examples: Semillon (Hunter Valley, Australia; Graves, Bordeaux, France). Chardonnay (Burgundy, France; Chablis, France; Yarra Valley, Australia; Hunter Valley, Australia) Sauvignon Blanc (Marlborough, New Zealand; Graves, Bordeaux, France; Sancerre/Pouilly Fume, France) Chenin Blanc (Vouvray, Loire Valley, France; Swan Hill, Australia). Marsanne (Côtes du Rhône, France; Goulburn Valley, Australia)

Light-bodied white wines require lower alcohol - thus grapes are picked at 10-12 degrees Baumé, whereas full-bodied white wines would be looking for 12-14 degrees Baumé.

As we discussed in must management, finer white wine grapes should be picked early in the morning to avoid high temperatures, which stimulate enzymatic or oxidative effects [eg: of mould] on the juice.

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Must Handling

When making white wines, the juice and skin are usually seperated quickly to avoid skin colour and phenolic components permeating the wine. Fuller-bodied white wines are the exception - they do involve a small degree of skin contact to add complexity.

'Free-run' juice [seperates from the grapes with minimal pressing - usually just the weight of the grapes in the container] makes the best fine white wines. Juice acquired through pressings are also usually too high in phenolics for fine wines, so are usually either used for a lesser quality wine, or perhaps treated with a tannin extraction agent to save them.

In warmer regions, acid [usually tartaric or sulphuric] is added to balance and lower the pH of the resulting wine.

The white wine must is also chilled to inhibit natural microflora [yeasts] interfering with the fermentation. This is important for fine wines - the winemaker needs control of fermentation to maintain delicacy. Broad, yeasty characters are not winners in fine Rieslings.

In some fuller-bodied white wines, though, the involvement of wild yeasts is encouraged to create greater complexity.

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Light-Bodied, Dry Whites

For Light-bodied, dry white wines, grapes must be in good condition, picked at low sugar levels and at cool temperatures, and need to be free of fungal disease.

The juice needs to be low in solids [so is clarified] and kept away from oxidation [so is kept cool and covered with inert gas blankets to fill head-space in containers].

Bitterness is not a welcome quality of these wines, so hard pressings are avoided, and usually only the free-run and gentle pressing juices are used. Hard [sometimes called 'third' pressings] are often discarded or used in base wines for cheap cask styles.

Fermentation of light-bodied dry white wines usually occurs at lower temperatures [10-15 degrees] to retain delicate aromas. The winemaker monitors fermentation several times per day to ensure it stays on track.

The resulting white wines are refined to remove any solids. What solids, you say, if the juice is clarified? Well, the yeast needs something to feed on, so sometimes the winemakers add bentonite. This, along with any other sediments produced during the fermentation process.

These white wines are usually bottled straight away or stored in stainless steel tanks if necessary with inert gas filling any head-space in the tank to avoid oxidation.

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Full-Bodied, Dry Whites

With full-bodied dry white wines, the grapes again need to be in good condition, free of disease, but picked at higher sugar levels (with consideration given to balanced acidity and flavour).

Harvesting of grapes for this style needs to take place in cool conditions, as with light bodied whites, however protection from oxidation is not as stringent. High levels of oxidation will make poor wine, so grapes are still protected with sulphur dioxide as early as harvesting stage.

Juice for full-bodied dry white wines needs to remain flavoursome and not be over the top in terms of phenolics - however some contribution is required to get that fuller body.

Again, for better quality wines without bitterness, hard pressings are not used.

Fermentation doesn't necessarily have to take place under cooler temperature conditions. This style of white can have many variations, and manipulation of the fermentation temperature is one way of increasing complexity in the resulting wine batch. Normally, the ferment temp is around 15-18 degrees. Fermentation is checked up to four times a day to monitor the wine.

Partial fermentation of fuller-bodied white wines can also take place in oak barrels. This means a portion of the wine is put into barrels, and often blended back into the batch at a later time. Too much oak is over-powering for white wines.

After fermentation, wines are chilled and given time for yeast lees to settle to the bottom. The clear wine is racked off the top, and often sulphur dioxide is again added to inhibit oxidation - particularly in hot regions.

Next the wines are clarified to different degrees - depending on the style of wine the maker is looking for, and sometimes sent to oak barrels for maturation before bottling.

Sometimes to increase a white wine's complexity, the yeast lees are left in the wine during oak barrel maturation. The winemaker stirs them through regularly. Yum.

Finally, when all this is done, wines are often blended and stabilised with fining agents before bottling.

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Sweet White Table Wines

Despite common misconception, sweet white wine is not a term reserved for dessert wines. Sweet white wines can come in a variety of styles at a variety of price and quality ranges, and raising the sugar levels in the wines can come from a variety of methods.

Cask wines

... are usually sweetened dry base wines. Sweetening is done by addition of juice of much sweeter grapes, such as Muscat Gordo.

Bottled sweet wines

... are made from grapes which have high natural sugar levels and are often late-picked to ensure these high levels.

Dessert wines

... are made from grapes infected with Botrytis cinerea - or "Noble Rot" as it's sometimes called.

These wines are fuller-bodied, and exhibit strong aromas and flavours of botrytis - ie apricots or orange peel - rather than the varietal characters of the grape, depending on the degree of infection by the rot.

Botrytis cinerea is actually a fungus or spoilage organism. It affects many fruits and vegetables - but not to the positive degree shown in wine. This fungus actually infects the grapes, causing them to shrivel with dehydration, therefore increase in sugar concentration, as well as metabolising tartaric acid in the grapes.

Botrytis also increases glycerol levels, resulting in silky, heavy and smooth mouthfeel of the wines.

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A word on Chaptalisation

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.

There's more than one way to skin a cat, they say. It's no different when it comes to increasing sugar in wines.

Other than botrytis infection, fermentation may be stopped early to leave a higher level of residual sugar in the wine. This can be done by cooling to stop fermentation, followed by filtering to remove yeast. Addition of SO2 also stops or slows fermentation but isn't the method of choice when making sweet white wines.

Or perhaps sweeter, unfermented grape juice [ironically called 'sussreserve"] or concentrate can be added.

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Further Reading: