Wine Appreciation Course
© Tom Cannavan, 1998
Part 4: Sparkling, sweet and fortified wine
All sparkling wines start life as still wines and have the sparkle added later. The crucial
factor in the quality of every sparkling wine is how the fizz is added.
The fermentation process naturally produces carbon dioxide gas (CO2) - the
waste product of the yeasts devouring the sugars. In still wine making this gas is allowed
to escape. In sparkling wines, the CO2 is retained, dissolving within the wine the wine which is kept under
When it is released, the CO2 bubbles to the surface.
The method for producing a wine filled with CO2 varies from the very time-consuming and
expensive Champagne method of natural, secondary fermentation in individual bottles, to
the inexpensive and easy method of squirting industrial CO2 into cheap, still wine.
The Champagne method
The Champenois are justifiably proud of their wines and the age old methods used in their
creation. Legend has it that the method was invented by a monk and winemaker named Dom
Pérignon. Champagne itself can come only from a very well defined area in the north east of
France, but many quality wines are made using the "Méthode Champenoise" (this term is no
longer allowed on labels, so the term "traditional method" is often used instead).
First of all, a high quality, dry white wine is made (usually from a blend of chardonnay,
pinot noir and pinot meunier grapes) with "ordinary" tank fermentation. Once the
wine is complete it is placed into special, heavyweight bottles and a fresh dose of
yeast and sugar is added. The bottles are then capped and placed in the cool
cellars of the winery for up to 2 years. During this time, a secondary fermentation takes
place. The yeasts and sugars create CO2
that, because it is in a sealed container,
cannot escape so dissolves into the liquid. In the early days Champagne production
was a dangerous business - cellars were destroyed by exploding wines. Controlled
production methods and stronger bottles have eliminated that risk.
The problem with this technique is the deposit of dead yeast cells that collects in the bottle.
In still wines these would simply be filtered out, but since that would also remove the bubbles,
another method had to be found. This process is known as Remuage: an action whereby each
bottle is shaken lightly, revolved and its position adjusted, so that over the course of a few weeks
the bottle ends up upside-down with the dead yeast cells captured in the neck of the bottle.
|The Remueur can precisely adjust 40,000 bottles per day.
At this stage the inverted bottles are carefully transported to a freezing tank. The necks are
dipped in, just to the level of the gathered sediment, which freezes into a solid "plug" of dead
yeast cells. The caps are removed and the gas pressure shoots the plug out. Depending on
the style of wine being made (dry, medium or sweet) the bottles are topped up with a "dosage"
of reserved wine and sugar. The bottles are corked, wired and at that stage, the Champagne is complete.
Though this process is long, expensive and labour intensive, no other method produces
wines with such fine and persistent bubbles and such a creamy complexity on the tongue.
Photo © Cephas
The tank method
This is a different process by which good quality bubblies can be made. Here the secondary fermentation
still takes place naturally, by adding new yeast and sugar to a finished wine, but instead of taking
place in bottles, the wine is held under pressure in large sealed tanks so that the equivalent of
several thousand bottles re-ferment at the same time. The wine is cleared of sediment and bottled
under pressure, directly from the tank. The bubbles are a little larger and disperse more quickly, but
the tank method can produce good results.
The transfer method
This is a less common system for creating a sparkling wine. Here, secondary fermentation takes
place in individual bottles - like Champagne - but instead of the expensive remuage process, the wine is cleared by
filtration and is then pumped, under pressure, into clean bottles.
Sweet (or dessert) wines
Like sparkling wines, there are a variety of methods for making sweet wines. These vary from
cheap and easy, to some of the most labour intensive and expensive processes in the wine
making world. We are talking here about fully sweet wines, often drunk with desserts, though
the French like to partner the finest foie-gras with a luscious Sauternes - perhaps the king of sweet wines.
Like so many aspects of wine making, the discovery that grapes left on the vine until they rot
can produce beautiful wines, was probably yet another accident.
|Botrytis is a fungus which may attacks grapes, usually in the cool of late autumn. It occurs in the
early morning mists which form in vineyards sited near large bodies of water. The fungus wraps itself
around the grapes and spores puncture the skin, drawing off water and leaving the grape shrivelled.
If left unchecked, botrytis will kill grapes and can be a big problem to vine growers. In some unique
locations (Sauternes in France, parts of Germany and Austria for example) the vineyards are sited
such that they also get maximum exposure to the sun.
In good years, the warmth of the sun as it rises
kills off the fungus, leaving the grapes shrivelled and unsightly, but tasting delicious: full of the sugar
and glycerine which was left behind.
Photo © Cephas
Vineyards for botrytis wines are harvested by hand, so that only those individual grapes
affected by the "noble rot" are selected. Often the same area will be picked over several times
so that grapes can be picked in ideal condition. The wine is then made using the normal method
for white wines, but the high sugar and glycerine content means that the wine is sweet, luscious
and full-bodied. Because grapes high in natural acidity are used (sémillon, sauvignon blanc,
riesling, gewürztraminer) the wine is not at all cloying. Though sweet, the best wines are balanced
and full of subtle flavours that linger on the palate.
Botrytis wines are always expensive and often bought by the half bottle. With the unpredictability
of the harvest and the labour intensive methods used, it is perhaps easy to see where the money goes.
Other sweet wines and methods of production
Some other sweet wines are produced from grapes that are over-ripened, but not rotted. This
can be done by simply leaving the grapes on the vine for longer than usual, or harvesting the grapes
as normal but leaving them spread out to dry on mats so that they shrivel in the sun and air. One
interesting, rare and expensive form of sweet wine is the ice-wine (in German, Eiswein) of Germany,
Austria and Canada. Here the grapes are left on the vine into the dead of winter - often into the new year.
On a suitably freezing cold night the grapes are harvested. Most of the water content of the grapes has
turned to ice and this is expelled from the grapes leaving only the sugars and acids behind in the pulp.
A wine is made from this which is very luscious and sweet.
Another group of sweet wines are sweet because fermentation is stopped at a fairly low alcohol level.
At that point, there is still plenty of natural sugar that has not been consumed by the yeast, so the resulting
wine is naturally sweet. Fermentation is usually stopped by filtering out the yeasts, but in some wines the
fermentation is stopped by adding spirit to the tank: this is the basis of the great sweet, fortified wines such
as Port and Madeira, as we shall see in the next section.
The cheapest method of making a dessert wine is simply to add sugar. In the best cases this will be
natural grape sugar, in the worst, sacks of cane sugar. Although these wines are sweet - and may
please some palates - they are usually lacking in balancing acidity and interesting flavours.
The term fortified indicates that the wine's alcoholic strength has been boosted by the addition
of spirit, usually a grape based spirit, like brandy. Fortified wines can be sweet or dry,
depending on whether the spirit is added during or after fermentation of the base wine. The
family of sweet fortified wines include Port, Madeira, Malmsey, Vermouth and Muscat de
Beaumes de Venise. Again, the quality of these is only as good as their components: a good
base wine and a good quality spirit.
About half way through fermentation (with an alcohol level around 5°) a measure of spirit is
added to the tank. This immediately raises the alcohol level. Yeast cannot survive in alcohol
levels much above 13/14°, so the fermentation stops and all the unfermented sugar is left in the
wine. The resulting wine is both strong and sweet. It is normally transferred to oak barrels at that
point for ageing.
Some of the world's great fortified wines include:
Originating from the Douro valley of Portugal, port comes in various styles and
quality levels. In particularly good years (usually two or three per decade) a "vintage" year is
declared and a vintage port is released. Vintage ports are the aristocrats of the port world and
often take around 30 years after release to develop into truly great wines. These should not be
confused with Late Bottled Vintage (or LBV) ports: these are ports which have been matured for
longer than ordinary ruby or tawny ports in the shippers' cellars, but they are not true vintage ports
of a great year. LBVs are ready to drink when they are released.
From the island of the same name, Madeira is unique in that after being made - in
much the same way as port - it is cooked. The wine is placed in very hot vats (over 50° centigrade)
for 90 days. Once again this was an accidentally discovered technique - Madeira wines being shipped
in the holds of sailing ships on long voyages were kept in very hot conditions which seemed to
caramelise the wines - a flavour that people seemed to enjoy.
This fortified wine (usually manufactured on an industrial scale in the north of Italy) is
flavoured with wormwood or other herbs.
Sherry, from Jerez in Spain, is perhaps the greatest wine made by the post-fermentation
method. In other words, unlike port, the spirit is only added after fermentation is complete. All
sherry therefore, starts life as a completely dry style. Varying amounts of sweet reserve wine are
added back in before bottling, according to the style of sherry being made.
Another unusual feature of sherry making is the "solera" system of ageing. In the
solera system, wine from many vintages is matured in the cellars in separate casks.
The casks containing the oldest sherry are constantly topped up with wine from the
second oldest casks. These in turn are topped up with wine from the third oldest
casks, and so on until the newest casks - from the current vintage. In this way,
the style of sherry can stay much the same from year to year as all sherry is a
blend of several vintages.
Fortified wines typically range from around 16° to 23° of alcohol - about double the strength
of ordinary wines.
Sparkling, sweet and fortified wine tastes and styles
There is a huge variation in terms of style and taste amongst these groups of wines.
Here are a few pointers:
can be made white or rosé. Although rare, there are
examples of red sparkling wines, such as the deep red, sparkling syrah from Australia.
Most Champagnes tend towards a dry, elegant style, but many other sparkling wines
(such as Asti-Spumanti for example) are lighter in alcohol and sweet, or semi-sweet.
have varying levels of sweetness and are often a golden yellow colour.
Their taste is often described as honeyed, whilst toffee and caramel notes are common too. Many
will display flavours of "white" fruits: peaches, pears, melon, etc.
here the overwhelming flavour comes not from the wine at all, but from the herbs used
as flavouring agents.
comes in many styles and quality levels, but the characteristics are just like those of fine red
wines: vintage ports can be tannic and overpowering when young, but can mature over many
years so that the fruitiness and sweetness of the grapes re-emerges.
also appears under a huge variety of guises. Most sherries are commercial blends,
made with consistency in mind: to taste the same year after year in a pleasant but uncomplicated
style. There can be a lot more to sherry than that however: some fine, old, dry sherries develop
wonderful walnutty, warm scents and flavours quite unlike any other wine. The finest, true fino sherries
are produced when a strange substance called "flor" grows on the top of the open cask as the sherry
ages. Flor is a yeast compound, which prevents the sherry from oxidising and adds subtle complexity to
the flavour. Most sherry is made principally from the palomino grape, but look out for sherry made mainly
from the Pedro Ximénez grape: these are intensely sweet: wonderful poured neat over good vanilla ice-cream!