Updated: Jan 16, 2020
Wine is fermented grape juice but its type and style depend on how it is made. Types of wine distinguish winemaking processes, resulting in still, sparkling, or fortified wine. Styles of wine are differentiated by organoleptic properties, such as color or taste. The winemaker and appellation regulations determine the style of each type of wine.
You're more likely to make better wine if you start with better grapes so in many ways viticulture is the first step of winemaking. However, this article will focus on winemaking beginning with the harvest. The timing of the harvest is affected by grape variety, weather, style of wine to be made, physiological measurements, and appellation regulations.
Grapes are harvested by hand or by machine. A manual harvest may be by cluster or by berry, Clusters allow the winemaker more options when making wine. Making several passes through the vineyard, picking berry by berry, allows wines to be made from grapes with specific traits like botrytised berries. A machine harvest is more economical but slaps the berries off the vines rather roughly, though I'd expect the technology to improve. Once harvested, handling of the grapes matters. If you put the grapes in a large container, gravity will break the skins of the berries at the bottom, exposing the released juice to oxidation. Sparing use of sulfur dioxide or a blanket of heavier than oxygen inert gas, picking when cool, and rapid transportation to the winery are the main tools to keep the grapes fresh.
After harvest the grapes are delivered to the winery and may be destemmed and sorted to remove stems, leaves, dirt, insects, critters, and diseased or sub-par grapes. Agrochemical residue, animal urine, and other MOG that cannot be removed by sorting, presumably do not survive the rest of the winemaking process as winemakers don't wash their grapes.
White, orange, pink and red still wines are made with many similar steps but in an order suitable for obtaining the desired style. White wines separate the juice from the solids before fermentation while other styles ferment first. Blue wine is an organic beverage with no denomination of origin, produced by one company; it may be generous to call it wine. Constructed wines and spirits (e.g., Replica Wine and Endless West) may or may not be regulated under the U.S. Department of the Treasury Alcohol and Tobacco Tax and Trade Bureau (TTB) or the U.S. Department of Justice Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) but I will not discuss them here.
Despite similar color, orange and pink wines taste different because of how they are made.
Orange wine is made from white grapes using the process normally used for making red wine, namely by fermenting the juice with their skins for several days or longer, and often with minimal additives. Appellations producing orange wine classify them as white wine. Pink wine is made from black grapes, fermenting the juice with their skins for a few hours.
When making white wines the grapes are crushed immediately after harvest. Crushing means the grapes are ripped open, releasing the free-run juice. If harvested by cluster the grapes are usually destemmed. Sulfur dioxide is added at this stage to prevent premature fermentation, oxidation, and spoilage, and it helps to break down sticky pectin. Sulfur dioxide passes through the cell membrane of microbes and renders them harmless by changing the properties of its proteins and enzymes. Aromatic grapes may benefit from skin contact ("maceration pelliculaire") with the free run juice at low temperatures or by leaving the grapes in a cool place overnight before crushing. To minimize extraction of harsh polyphenols, the free-run juice should be drained without disturbing the skins.
The crushed grapes are then pressed to extract the remaining juice. Pressing means releasing the remaining juice by rupturing the tougher cells near the skin under pressure.
The winemaker chooses how much of the generally inferior press juice to include in the blend depending on the style and vintage conditions. Most white wines are effectively press wine as the harvested grapes are usually pressed, not crushed, after destemming.
After pressing, the remaining solids, referred to as pomace, are disposed of or distilled into a pomace brandy known by many names including Marc (France), Grappa (Italy), Orujo (Spain), Tresterbrand (Germany), and Raki (Greece).
The juice, referred to as must, is then chilled and left to settle ("débourbage") for about a day so the larger particles can fall to the bottom of the vat. Depending on appellation regulations, acid or sugar may be added before fermentation to adjust the acidity and alcohol in the final wine.
After clarification by settling, alcoholic fermentation is started. Temperature during fermentation of white wines is usually maintained between 59-68°F (15-20°), depending on the grape variety and wine style being produced. Temperature control during fermentation is important because if the temperature is too cool a pineapple aroma dominates and if the temperature is too warm the wine becomes dull.
Primary, or alcoholic fermentation, means yeasts, a single-celled fungi, convert the sugar in the must into ethanol and carbon dioxide. Fermentation may be started using wild yeasts (non-saccharomyces) or by adding cultured yeast (usually saccharomyces cerevisiae or saccharomyces bayanus) from companies like Lesaffre/Redstar and Lallemand. Yeasts proliferate with oxygen but must be switched to anaerobic mode after fermentation starts or water rather than alcohol would be produced. Fermentation in wood barrels achieves the greatest complexity though stainless steel tanks are often used for fresher styles.
If most of the sugar is converted into alcohol, the wine is referred to as "dry". The winemaker may also decide to leave residual sugar in a wine so it tastes "off-dry" or "sweet" by filtering out the yeast or by adding neutral grape spirit which kills the yeast.
Secondary, or malolactic fermentation (MLF), also known as malolactic conversion (MLC), means lactic acid producing bacteria (LAB) convert the malic acid in wine into lactic acid and carbon dioxide. Oenococcus, lactobacilllus, and pediococcus are the main types of LAB. MLF reduces acidity and increases complexity by generating diacetyl, the source of a buttery character. MLF also increases stability by consuming bacterial nuturients. However, MLF also reduces some fruity esters so is typically not used to make many white wines other than Chardonnay. Many sweet styles of white wine do not use MLF because they ferment grape juice that has been concentrated by noble rot, freezing, or drying, and has little malic acid to soften.
To clarify the wine it is then transferred ("racked") into another container to remove the dead yeast and particulates, referred to as "gross lees", which can impart a bitter taste.
After fermentation, the wine may rest on its lees ("sur lie") for many months to impart greater complexity, flavor, and usually a "toasty" quality to the wine. Lees are the yeast (mostly dead) and particles of grape skin and cells that lie at the bottom of the barrel at the end of fermentation. As the yeast decomposes it creates a reductive environment which may result in hydrogen sulphide being produced. To avoid this rotten egg smell, oxygen must be introduced by stirring the lees ("batonnage") or by rotating the barrels.
The winemaker controls the style of the finished wine by blending at this point. Blending means mixing wines that have been made using different methods, or from grapes grown at different places, or from different grape varieties. Blending should occur before further clarification or stabilization treatments because it can render the wine unstable again.
The wine may then be stabilized, meaning that the wine is processed to keep it clear after bottling at both high and low temperatures. Fining wine heat stabilizes it by removing tannins and unstable proteins which cause haze. Fining agents, which have a negative charge are attracted to the unstable proteins in wine that have a positive charge and form a precipitate that can be removed by settling or filtration. Albumin (in ox blood and egg whites), gelatin (animal-, fish-, or vegetable-derived), and casein (in milk) proteins can be used as fining agents but some may wish to avoid use of animal based products, even if not a component of the final wine. In this case, bentonite (a clay formed from volcanic ash) and for white wines only, silicon dioxide (in silica sol), PVPP (a plastic), or activated charcoal may be used as fining agents. Cold stabilization follows, meaning tartaric acid is either precipitated out of the wine or its crystallization is prevented. Stabilization should not have a noticeably negative effect on the quality of a wine if properly carried out but low intervention winemaking may be the best approach.
After several months, and several rackings, the remaining particulates, referred to as "fine lees" will have settled out. If the winemaker isn't satisfied with the speed or clarity achieved by racking, a centrifuge (flushed with nitrogen to prevent oxidation) or filtering may be employed, though these methods may remove desirable flavors.
At this point white wines will be bottled, corked/capped, labelled, and packed. Some white wines, particularly those from France, Germany, and Spain will benefit from bottle age.
When making red wines, before the crusher-destemmer was introduced, grapes were fermented without destemming. This is still commonly practiced in Bourgogne (Burgundy). If uncrushed, some of the sugar in the grape berries will be converted into ethanol via enzymes rather than yeast in a process known as carbonic maceration, commonly used in Beaujolais. Stems, sometimes roasted, may also be added to absorb sugars and acids in the must and serve as channels for the liquid to run.
At this point the grapes are crushed and sulfur dioxide is added to protect the must. Although it sounds rougher than pressing, crushing simply breaks the berry skins, releasing the free-run juice. The key point is that the juice and the skins are fermented together because the skin, not the juice, imparts color to most red, pink, and orange wines.
The must (juice and skins) may undergo a cold soak before fermentation to extract fruit aromas without tannin. Alcoholic fermentation runs about 5°F warmer than for white wines, and lasts for up to 3 weeks. Color and tannin can be extracted from the skins by several methods that keep the skins mixed with the juice. The gentlest method, known as "punch down" ("pigeage"), pushes the skins that have floated to the top of the vat back into the must. A less labor-intensive method known as "pump over" ("remontage"), sprays juice pumped from the bottom of the vat over the top and results in a greater level of extraction. The "rack and return" method (délestage), empties the fermenting must into another tank and then returns it to the original vat where the skins remain at the bottom. This process is the fastest and most thorough of the three. The alcohol in the must extracts the pigment and tannin from the skins. Varying the timing and frequency of punch down, pump over, or rack and return allows winemakers to control how much extraction takes place.
Primary fermentation may be followed by maceration. Maceration means soaking the must to extract phenolics (tannins, color, flavors) from the skins, seeds, and stems into the juice. The free-run wine ("vin de goutte") is drained into a tank or barrel and the remaining must is put in a press to yield a more robust press wine ("vin de presse"). After pressing the remaining solids are either disposed of or distilled. The wine is then racked into another container to remove the gross lees, followed by secondary fermentation. While MLC is often skipped when making white or pink wine it is usual when making red wine.
Barrel maturation at this point allows the wine to acquire flavors from the barrel, soften its tannins, deepen its color, increase the complexity of its flavors, and slowly stabilize and clarify. Blending may occur before or after ageing in the barrel ("elevage").
Red wines are then stabilized, clarified, and bottled, corked, and labelled as with white wines. Finer red wines, as with some fine white wines, also benefit from bottle ageing.
When making pink wines winemakers may or may not have a choice as to the production method, depending on regulations and tradition. The "bleeding" method ("rosé de saignée"), also called short maceration (rosé de macération), begins as for making red wine but drains out some pink juice after macerating less than a day, and then proceeds as for making white wine. The remaining juice is used to make a more robust red wine. Making two wines from the same grapes allows the pink wine to be sold earlier than the red wine which may benefit from ageing. The "direct press" method is used to make delicate pink wine and is essentially the same as for making red wine but the juice remains in contact with the skins only a few hours. Blending red and white wines together to make pink wine ("rosé d'assemblage") is not common except for sparkling wine. Rarely, pink wines may be made by removing some color from red wines using charcoal, presumably because the lighter color boosts sales.
A few examples of appellations that make pink wine using each method may be useful.
Direct Press: Provence, though the winemaker may choose to use the bleeding method
Blending:: Champagne, though some producers (e.g., Francis Boulard & Fille) use the bleeding method. Some new world winemakers, such as some from New York and New Jersey, also blend red and white wines to make pink wine.
Sparkling wine production begins with making still wine. Top quality sparkling wines and white wines made from black grapes are often harvested by hand and pressed without destemming.
There are several methods used to make sparkling wine which all entail dissolving carbon dioxide in the wine. Most methods also involve removing the lees remaining after fermentation because the lees makes the wine cloudy. As you might suspect, the main determinant of the quality of a sparkling wine is the quality of the wines it is made from. However, since the still wines used to make sparkling wines (called base wines) are somewhat bland and quite acidic, balance is key to making more than a carbonated wine.
Both pink and sparkling winemakers believe it is more challenging to make their wine than red wine. While pink wine producers have to balance color with tannin extraction I suspect it is more challenging to make good sparkling wine because minor faults in the base wine are accentuated by the presence of bubbles and because blending ("assemblage") is more art than science. While some champagnes like Jacquesson and some grower champagnes promote vintage or terroir differences like fine still wines, most focus on producing a consistent house style, year after year. They do this by blending "reserve wines" from previous vintages (at least 15% of each harvest in Champagne is reserved for future blends) with typically 80% of the base wines from the current vintage.
Sparkling wine is usually made using the traditional, transfer, or tank methods. Each method starts by blending base wines (and optionally reserve wines) as a "cuvee" and adding sugar and yeast (referred to as liqueur de tirage). There are also variations on these methods which will be discussed below.
Second fermentation, not to be confused with secondary fermentation described above, means inducing another alcoholic fermentation and trapping the resulting carbon dioxide in the wine rather than releasing it in the air. This produces the bubbles in sparkling wine.
The traditional method (also called the classic method, Méthode Champenoise in Champagne, and Méthode Cap Classique in South Africa) then puts the cuvee in the bottle it will be served from, adds a plastic cylinder called a bidule in the neck of the bottle, then closes the bottle with a crown cap (a "beer bottle cap"). After second fermentation the wine is aged on its lees for additional complexity and then clarified by removing the lees via riddling (coaxing the lees into the neck of the bottle) and disgorging (freezing the neck then removing the crown cap so the bidule and lees pop out). The bottle is then topped up with a mixture of wine and sugar syrup known as dosage ("liqueur d'expédition") before corking and caging (securing the cork with a muselet wire cage), The dosage is used to create the desired sweetness in the wine.
brut nature (aka zero dosage): < 3
extra brut: 0-6
extra dry: 12-17
dry (aka sec): 17-32
doux: > 50
Note that the classification of sweet wine as "dry" defers to a tasting panel that noted that while Americans said they preferred "dry" wines, they actually liked sweet wines.
A variation on the traditional method, known as transversage, is usually used to fill bottles that contain other than 750 ml. After disgorgement, the wine is transferred into a pressure tank, dosage is added, and then the special size bottles are filled.
The transfer method (also known as Carstens in the U.S.) is another variation on the traditional method where riddling and disgorging are replaced by clarification in a pressure tank. After dosage is added the wine is put in a new bottle. However, the viability of this method is somewhat questionable because it still incurs the costs of second fermentation and aging in a bottle butproduces smaller and longer-lasting bubbles than the tank method.
Yeast can also be encapsulated in beads made of calcium alginate to optimize riddling. However, adoption has been slowed because the beads may break during disgorgement Yeast can also be added to a membrane cartridge in the neck of the bottle to eliminate riddling entirely. I suspect cost is the reason these technologies have not been adopted.
The tank method (also called the Charmant, Martinotti, Cuve Close, or bulk method) puts the cuvee in a pressure tank before second fermentation to eliminate the costs of second fermentation in the bottle, ageing on lees, riddling, and disgorgement. After dosage is added the wine is bottled, corked, caged,
The Asti method is a variation on the tank method intended to preserve the flowery characteristics of the Moscato Bianco variety. The must (not base wine) is added to a pressure tank with yeast but the carbon dioxide is allowed to escape until the alcohol reaches 5-6% abv at which point the valves are closed. After reaching the desired balance of sugar and alcohol the wine is cooled to freezing and held in tank until the producer is ready to bottle the wine. It is then clarified, filtered, bottled, corked, labelled, and packaged. Filtering is important to prevent the yeast starting primary fermentation again.
Very inexpensive sparkling wine can also be made using the continuous method where the base wine and tirage are pumped into a series of pressurized tanks. Yeast is added to the first tank continuously because yeast cannot grow under 5 atm of pressure. Dead yeast is trapped in the next 2 tanks and reacts with the wine. After four to five weeks, reasonably clear wine emerges after passing through the final tanks.
Sparkling wine can also be made without a second fermentation. The interesting methods start primary fermentation, stop it by cooling, then restart it by warming. The ancestral method (also called méthode rurale) is famous because it may be the first way sparkling wine was intentionally made. When wine is bottled without removing the yeast before all its residual sugar has been fermented into alcohol, primary fermentation can be restarted when the temperature of the wine rises. The resulting wine is usually sweeter and less fizzy than wine made using the traditional method. Neither tirage nor dosage is added.
The Dioise method ("dee-wah") is a variation of the ancestral method used by cooperatives (Jaillance is dominant) to make the sweet Clairette de Die sparkling wine from the Clairette and Muscat Blanc à Petits Grains grape varieties, producing wine similar to Asti. The base wines are fermented in stainless steel tanks at low temperatures for several months. The wine is then bottled after filtering out most (but not all) of the yeast and fermentation continues until it reaches 7-8.5% abv. After lees aging and disgorgement the wine is filtered again and transferred into new bottles.
Carbonation, also known as the industrial, injection, soda, or bicycle pump method, injects carbon dioxide gas into a tank of still wine which is then bottled under at least 3 atmospheres of pressure. The resulting aerated wine has many large bubbles that rapidly dissipate.
Each sparkling wine production method is usually dominant in specific regions:
Traditional: high quality sparkling wine made in France (Champagne and Crémant), Spain (Cava), Italy (Franciacorta, Alta Langa, Oltrepo Pavese Metodo Classico, Trento), the United States (Napa and Sonoma), and South Africa.
Transfer: sparkling wines produced in Australia.
Tank: inexpensive sparkling wines from Italy (Asti, Lambrusco, Prosecco), Germany (sekt), and the United States.
Continuous: very inexpensive sparkling wine from Russia, Germany, and Portugal
Ancestral: Blanquette Méthode Ancestrale, Clairette de Die
Carbonation: Bulk sparkling wines from Argentina, Australia, South Africa, and Oregon
Fortified wine (also known as liqueur wines) differs from still wine because brandy has been added either during (mutage) or after fermentation to raise alcohol levels. Popular styles include Port, Madeira, Sherry, Marsala, vins doux naturels, Rutherglen stickies, and aromatized wines. Note that vins de liqueur and mistela are not fortified wines because they are made by fortifying grape juice rather than wine.
Port is a fortified wine from Portugal. While a large number of grape varieties (67 black and 47 white) are authorized for the production of port, the important black varieties are Touriga Nacional, Touriga Franca (formerly known as Touriga Francesa), Aragonez (Tinta Roriz, Tempranillo), Tinto Cão, Tinta Barroca, and Trincadeira (Tinta Amarela). The important white varieties are Malvasia Fina, Viosinho, Donzelinho Branco, and Gouveio (Verdelho)
Port vineyards are planted along the steep slopes of the Douro river. The continental climate becomes drier and hotter as vineyards progress from the Atlantic Ocean to the Spanish border in three zones: the Baixo Corgo, the Cima Corgo and the Douro Superior. Grapes for most of the best Port is grown in the middle zone.
The Instituto dos Vinhos do Douro e Porto (IVDP) prepares a beneficio each year indicating how many grapes from each quality level of vineyard (A-F) can be used to make Port. This regulation is intended to allow all 33,000 growers to make a living.
Port is produced by first rapidly extracting color and tannin within 36 hours, either by treading the grapes in traditional granite "lagares" or robotic lagars or by crushing the grapes using piston-plungers or autovinifiers. Fermentation continues in lagar or tank for 1 to 4 days until the wine is 6-9% abv at which time fermentation is arrested by adding 1 part brandy (aquardente 77% abv) to 4 parts wine. After aging at least 2 years in stainless steel or wood the quality is assessed and further maturation is based on the style produced.
The major Port styles are White, Ruby, Tawny, and Vintage but there are a dozen styles including subcategories. White Port is made from white grapes, non-vintage, and usually sold off-dry to sweet within 3 years. Ruby Ports may be basic (stored in inert vessels), Reserve (cask-matured up to 5 years), Late Bottled Vintage is aged between 4-6 years (traditional LBV is bottle-matured while modern LBV is fined and filtered). Crusted Ports are blends aged in wood an average of 4 years then bottled unfiltered and aged at least 3 years. Tawny Ports may be basic (lighter colored, can be blended with White Port), Reserve (blend of wines from different vintages and cask-matured at least 7 years), with an indication of Age (10, 20, 30, or over 40 years average age), or Colheita (vintage-dated and cask-matured at least 8 years). Vintage Ports are declared by each producer but approved by the IVDP, and bottled between 18 and 36 months without fining or filtration and best enjoyed after at least 20 years. Single Quinta Vintage Ports are from a single estate ("quinta") and may be declared in years when a full Vintage Port is not. Garrafeira Port is another style produced by Niepoort, aged in wood 3 to 6 years followed by aging in 2 to 3 gallon glass demijohns, sometimes for over 50 years, but it is very rare. The higher quality ports (Vintage, Colheita, Crusted, and unfiltered LBV) need decanting before consumption.
Madeira is a fortified wine from Portugal, grown on the mountainous island of Madeira in the North Atlantic, and made from four "noble" white grape varieties. Each variety is vinified in a particular style: Sercial is dry, Verdelho is medium dry, Boal is medium sweet and Malvasia (referred to as Malmsey) is sweet. Tinta Negra, a black grape variety, may be used to make less expensive Madeira in a range of styles. Hybrid varieties, widely planted after most vines were destroyed by powdery mildew and Phylloxera in the second half of the 19th century, may not be used to produce Madeira.
Madeira is fermented in temperature-controlled stainless steel tanks until the desired sugar level is reached. Grape spirit (96% abv) is added to stop fermentation and the wine is matured using either the canteiros or estufa method. Single varietal and vintage wines are matured in casks for at least 3 years on racks called canteiros which are heated to 86°F by the sun. Commercial non-varietal wines are pumped into stainless steel containers called estufas and heated to 113-122°F for at least 3 months before maturing in cask or vat in a cool area for at least 2 years.
Varietal wines made from noble grapes and matured by caneiros for at least 10, 15, and 20 years (and sometimes for more than a century) are referred to as Special Reserve, Extra Reserve, and Vintage (Frasqueira) respectively. Reserva wines aged at least 5 years (referred to as Colheita if vintage-dated) are usually made from Tinta Negra but may be varietally labeled if based on the noble varieties. Finest wines are made from Tinta Negra using the estufa method, aged at least 3 years, and labelled as Dry, Medium Dry (referred to as Rainwater), Medium Rich, or Rich.
Jerez-Xérès-Sherry is a fortified wine from Spain made from three white grape varieties, namely Palomino, Pedro Ximénez, and Muscat of Alexandria. The wine may be aged in the towns of Jerez de la Frontera, Sanlúcar de Barrameda, and El Puerto de Santa Maria. The wine takes its name from the town of Jerez; founded as Xera by the Phoenicians around 1100 BC, ruled as Xérès by the Romans in the first century BC, ruled as Sherish by the Moors in 711, and reclaimed as Jerez by Alfonso X of Castile in 1264. Most regions around the world that make a similar style of wine have agreed not to use the name Sherry (e.g., Australia and Canada use the name Apera, indicative of apéritif).
Sherry made from Palomino is fermented dry in stainless steel tanks. The wine is 11-12% abv when it is racked off its lees into large tanks and left unsealed so yeasts can form a thick layer on the surface called flor. Flor converts alcohol and oxygen into carbon dioxide and acetaldehyde (CH3CHO), which gives Sherry its unique flavor. Flor flourishes in the spring and fall and declines in the summer and winter because it prefers cool and humid conditions with alcohol levels below 15.5% abv. Wines with well-developed flor and a light body and color are initially classified as Fino while wines with little or no flor are classified as Oloroso. Finos are then fortified to 15% abv to promote the growth of flor while Olorosos are fortified to 17% abv to kill any flor. The wines are then racked into oak barrels for 6 to 8 months (a period called sobretabla) and reclassified. If the flor in a Fino wine has failed the wine is reclassified as Oloroso or Palo Cortado. Palo Cortados are rare Sherries of the highest quality and sell for premium prices. Amontillado is a Fino that was aged under flor (biologically) for 3 to 8 years and then matured further without flor (oxidatively). En Rama (raw) is a recent style of biologically aged sherry which is lightly filtered (1 micron versus the normal .4-.45 micron) so as to retain more flavor though it does leave flakes of yeast in the bottle. Barbadillo Manzanilla En Rama was the first such Manzanilla introduced in 1999 and Tio Pepe En Rama was the first Fino bottled in 2010.
Sherry made from Pedro Ximénez (PX) or Muscat of Alexandria (Moscatel) are sweet because the grapes are first raisinated to produce concentrated juice that yeast cannot ferment dry. The must is then fortified to 17% abv.
Most Sherry is aged for at least 3 years in 600 liter neutral oak barrels called butts kept 5/6 full. The wine matures in a bodega kept cool by the dry westerly Poniente wind or by air-conditioning. Maturation involves gradually moving younger wines into older wines in a system known as solera. Butts are arranged in levels which hold wines of different average ages. The oldest wine level is called the Solera while younger wine levels (3-14) are called criaderas. Wine for bottling is taken from the Solera level which is then replenished from every butt in first criaderas which is then replenished from every butt in the second criaderas and so on. The youngest wine is usually replenished with sobretabla wine but one solera system may feed into another solera system too. Producers may only bottle a third of the wine in a solera system each year so the blending achieved ensures consistency of style and quality.
Finos are rarely aged for more than four years and never more than 7 because the flor cannot be sustained. Oloroso, Amontillado, Pedro Ximénez, and some Moscatel Sherries are aged oxidatively. Amontillado is produced by feeding a mature Fino, fortified to 17% abv, into an Amontillado solera system. Sherries matured oxidatively can be aged up to 30 years, rising to 22% abv as water evaporates.
Sherry styles governed by the Consejo Regulador:
Vinos Generosos (dry Sherry):
Fino: 15% abv
Oloroso: up to 22% abv (can add PX)
Amontillados: up to 22% abv
Palo Cortados: similar to Oloroso and Amontillados
Vinos Dulces Naturales (naturally sweet Sherry):
PX and Moscatel
Vinos Generosos de Licor (Sherry sweetened by blending):
Pale Cream: Fino sweetened by Rectified Concentrated Grape Must (RCGM)
Cream: Oloroso blended with Vinos Dulces Naturales
Medium: Amontillado blended with Vinos Dulces Naturales
Aging for Manzanilla Sanlúcar de Barrameda DO must be carried out in Sanlúcar de Barrameda which is cool all year, ensuring a thick layer of flor all year, resulting in a more intense tangy aroma.
Manzanilla fina: Fino
Manzanilla pasada: Amontillado
Age Indicated and Vintage Sherries (Amontillado, Palo Cortados, Pedro Ximénez):
Vinum Optimum Rare Signatum (VORS): Very Old Rare Sherry is at least 30 years old
Vinum Optimum Signatum (VOS): Very Old Sherry is at least 20 years old
Añada: Vintage Sherries aged oxidatively in their original butt (not a solera).
Fortifying Jerez wine began in the 17th century to preserve it on long sea voyages. However, it is possible to make historical sherry without fortification or a solera system such as the single vintage sherries produced by Bodegas Luis Pérez. Regulations are being amended to allow wines fermented to at least 15% abv (Fino and Manzanilla) and at least 17% abv (Oloroso, Palo Cortado, Amontillado) to be classified as sherry. However, this pre-17th century method of Sherry production is not common.
Montilla, similar to Sherry, is made in the Montilla-Moriles appellation of Spain. The hot summers and cold winters impact both the viticulture (Pedro Ximenez thrives but Palomino does not) and winemaking practices (the flor is thinner). Fino and Amontillado styles are made from free-run juice while Oloroso styles are made from press juice and aged for longer in soleras.
Malaga is a fortified wine from Spain made from white grapes. (Pedro Ximenez, Alexandria Muscat and up to 30% of Doradilla, Lairen and Romé). Fortification between 15 and 22% abv may be before (Maestro) or during fermentation from fresh (Vino Dulce Natural) or raisenated (Tierno) grapes. Wines are matured in a solera system and classified by age as Pálido (less than 6 months), Noble (up to 3 years), Añejo (up to 5 years), or Trasañejo (more than 5 years). Arrope, a syrup made from unfermented grape must, may also be added to sweeten and color the wine (Dorado is uncolored, Rojo Dorado has up to 5% syrup, Oscuro has 5-10% syrup, Color has 10-15% syrup, and Negro has more than 15% syrup added). Popular styles include Pajarete (aged for at least 2 years with no syrup added), Lacrimae Christi (made from first press must and aged for at least 2 years), and styles designed for the British market that vary in sweetness.
Marsala is a fortified wine from Italy usually made only from white grapes, namely Grillo, Catarratto (Comune and Lucido), Inzolia, and Damaschino. The grape vines are best trained as bush vines ("alberello") and are aged in barrels that are not filled completely to encourage oxidation. The three main styles produced today are Marsala Fine (about 80%), Marsala Superiore (about 20%), and Marsala Vergine. These styles differ by what the wine is fortified with and how long it is aged.
Marsala Fine is intended for cooking, not drinking. It is at least 17.5% abv and matured for at least a year. Marsala Superiore is at least 18% abv and matured for at least 2 years; designated a riserva after at least 4 years in wood. These two styles are fortified with grape must that is cooked, fortified, or concentrated. These wines are designated dry ("secco" < 40 g/l RS), semi-dry (40-100 g/l RS), or sweet ("dolce" > 100 g/l RS). The color of these wines is gold ("oro"), amber ("ambra" must contain cooked grape must), or less commonly ruby ("rubino"). Rubino Marsala contains at least 70% black grapes, namely, Nero d'Avola, Perricone, and Nerello Mascalese.
Very little Marsala Vergine is produced though it is most similar to the original Marsala invented in 1773 by John Woodhouse. The wine is fortified with grape spirit ("acquavite") and/or ethanol. It is at least 18% abv and matured for at least 5 years in oak or cherry barrels; designated a riserva ("stravecchio") after at least 10 years in wood. If the wine is matured and bottled using a solera system ("perpetuo") it may be labeled "soleras". This golden-amber wine is dry and pairs well with strong cheese.
Vins doux naturels (VDN) is a fortified wine from southern France made by "mutage", that is, by stopping the conversion of sugar into alcohol before fermentation is complete. The grape spirit added to stop fermentation is 95% abv which increases the wine from about 6% abv to 15-18% abv. Although the spirit added to port has less alcohol (about 77% abv) Port has more alcohol than VDN because the added spirit is about 20% of the wine versus 5-10% for VDN.
The Roussillon region has five appellations that make VDNs in both oxidative and reductive styles. Oxidative winemaking means the winemaker deliberately exposes the wine to oxygen to achieve a particular style of wine. This contrasts with reductive winemaking where the winemaker minimizes exposure to oxygen throughout the winemaking process.
The Muscat de Rivesaltes appellation makes white VDN from Muscat Blanc à Petits Grains and Muscat d'Alexandrie. The Rivesaltes appellation makes red, pink, and white VDN based on Grenache. The Tuilé, Ambré, Hors d'Âge, and Rancio styles are oxidative while the Grenat and pink styles are reductive. The Maury appellation makes red and white VDN based on Grenache. The red Vendange/Récolte ("vintage") styles are reductive while the Hors d'Âge and Rancio styles are oxidative. The Banyuls appellation traditionally made an oxidative red wine aged in demi-johns left in the sun but many wines today are made in a non-oxidative manner. A small amount of white Banyuls is made from Grenache Gris in a reductive style. The Banyuls Grand Cru appellation makes oxidative style red wine in the best years from at least 75% Grenache Noir and is aged at least 30 months in small wooden casks.
The Languedoc region has four "Muscat de" appellations that make VDN in a reductive style from Muscat Blanc à Petits Grains: Saint Jean de Minervois, Frontignan, Mireval, and Lunel.
The southern Rhône region also has 2 appellations that produce VDN, Beaumes-de-Venise is similar to Languedoc VDNs and is the Rhône's only sweet still white wine. Rasteau makes red, amber, and brown Grenache-based VDN similar to those from Roussillon.
Rutherglen "stickies" are fortified wines from Victoria, Australia. Australia produces its sticky-sweet fortified wines from grapes that have begun to raisin on the vine (without noble rot) using mutage (fortification is performed during fermentation) and ages them in hot sheds using a solera system (so non-vintage). Rutherglen Muscat is made from Muscat a Petit Grains Rouge (Brown Muscat) while Ruthergelen Topaque (previously called Tokay) is made from Muscadelle. Both "stickies" are classified according to their residual sugar and average age proceeding from 180-250 g/l residual sugar aged 2-5 years to Classic (200-280 g/l, 5-10 years), Grand (270-400 g/l, 10-15 years), and Rare (270-400 g/l, 20 years). These delicious wines are ready to drink when bottled and do not improve with further ageing.
Aromatized wines are base wines flavored with botanicals that have been lightly fortified. They are often classified as Vermouth, Quinquina, and Americano based on by their primary botanical, namely, absinthium ("wormwood"), quinine, or gentian root. The categories are Vermouth, Quinquina, and Americano.
Vermouth is a fortified wine flavored with absinthium and other herbs and spices. Ancient cultures commonly added herbs and spices to their wines. The sweet (red) version was created in 1786 by Antonio Benedetto Carpano in Italy from Muscat Blanc à Petits Grains. The dry (white) was created in 1800 by Joseph Noilly of France.
Example brands for each style of fortified wine may be useful:
Bird, David, Understanding Wine Technology, 3rd Edition, DBQA Publishing, 2010
Robinson, Jancis, et al, The Oxford Companion to Wine, Fourth Edition, Oxford University Press, 2015
WSET, Wines and Spirits, Understanding Style and Quality, WSET, 2011
Grande Passione provides excellent study aids in the form of free spreadsheets