Dessert Wines – Fortified Wine Production

There are numerous types and styles of fortified wine. All involve the addition of grape spirits to still wine to increase the total percent of alcohol in solution above a 15% threshold. Many involve adding this spirit before the still wine is finished fermenting, leaving a high percentage of residual sugar, making a sweet, and fortified wine (i.e. Port). Others involve adding a sweetening agent during the process to effect a change in residual sugar content if desired (i.e Sherry). The two most popular and well-known fortified wines are Sherry and Port.

Dessert Wines


Fortified Dessert Wines

Non-Fortified Dessert Wines


Sherry is a fortified wine (white) from Spain that employs three important aspects: aging, controlled oxidation and fractional blending (via the solera).

The aging of sherry takes place in one of two ways:

  • Biological Aging – The sherry ages in contact with a film of yeast (flor) that changes the characteristics of the wine by metabolizing elements within the wine and controlling the rate of oxidation.
  • Physiochemical Aging – The sherry is in direct contact with air and its immediate oxidizing effects.

Sherry falls into the following categories:

  • Fino (flor)
  • Manzanilla (A type of fino)
  • Amontillado (flor w/oxidation)
  • Palo Cortado (no flor)
  • Oloroso (no flor)
  • Raya (no flor)

The production of Sherry uses the following steps:

  • Pressing – Extracts more of the juice for fermentation and removes pips, seeds and stems.
  • Acidification – The addition of acid (which is a food source for the flor), if required.
  • Settling (debourbage) – Allows for some clarification before fermentation.
  • Fermentation – The conversion of grape juice into wine.
  • Classification (fino/oloroso) – Process of selecting a style of Sherry, based on quality.
  • Fortification (15% fino/18% oloroso) – Addition of neutral grape spirit.
  • Aging – The additional cask aging of the wine.
  • Flor growth (finos) – Biological aging process.
  • Aging (olorosos) – Physiochemical aging process.
  • Solera – The fractional blending of wines to establish consistency of style/type.
  • Working the scales – The transfer of newer wines to older wines to refill the solera.
  • Blending – The mixing of various wines to yield the desired style.
  • Finishing – The addition of a sweetener, if desired.


Marsala wine is produced on the island of Sicily in Italy in a process very similar to Sherry where the fortification occurs after fermentation and the wine is aged in a set of casks much like a solera. Also, for sweet style Marsala, the sweetening agent is blended into the dry, fortified wine.


Port wines (and wines called vin doux naturel in France) are fortified with alcohol during the fermentation process to allow the wine to retain considerable sweetness.

In the process of making Port, Brandy is added to the fermenting wine after about 72 hours, when the must reaches approximately 13.5 brix of sugar. At this point the wine has a percent alcohol of 20% and a residual sugar percentage of 10%.

There are two types of Port: Bottle-aged and Wood-aged.

Bottle-aged Port:

  • Vintage – horizontal blend of grapes & vineyards; unfiltered; 10 years maturity minimum.
  • Single Quinta Vintage – blend of many grapes from one vineyard.

Wood-aged Port:

  • Ruby Port – Aged in oak 3 years – vibrant.
  • Tawny Port – Aged in oak 3 years – amber.
  • LBV – Aged 4-6 years in oak – vintage dated.
  • Vintage Character – Aged 4-6 years – cross Ruby Blend.
  • Colheita – Single Vintage Tawny – At least 7 years old.


Madeira is a fortified wine made on the island of the same name off the coast of Portugal. As with Sherry there are sweet and dry style Madeira. However, unlike Sherry, the sweet varieties are made like to the Port wine process, wherein the fermentation is halted with alcohol prior to all of the sugar being fermented. Dry style Madeira is essentially like Sherry, in that the fortification of the wine occurs after a complete, dry fermentation.

Another interesting characteristic of Madeira is the heavily caramelized, maderized flavor that is the wine’s trademark. Interestingly, today this characteristic is the result of a baking process that occurs during the aging of the wine in a baking shed called an estufagem. The process was actually discovered as a result of the long sea voyages of the 17th century, where casks of Madeira were shipped in the warm, humid holds of sailing ships for months at a time. When the Madeira finally reached its destination, it was found to have greatly improved as a result of the slow baking, hence the employment of the modern technique of the baking shed today.

Madeira is considered ageless, since the usual factors that destroy a wine, heat and oxygen have already done their worst to the wine during its cask aging process. As a rule, vintage dated Madeira must spend at least 20 years in cask. Younger Madeira cannot be vintage dated. Madeira that is labeled solera will carry the date of the original cask, so a wine that is labeled solera 1815 is wine from blending casks that were first started in 1815.

The varieties of Madeira are named for the principal grape variety that goes into making the wine. The varieties of Madeira are as follows:

  • Sercial – Driest style Madeira, more appropriate as an aperitif than for dessert.
  • Verdelho – Medium-dry style, more appropriate as an aperitif or cooking wine.
  • Bual – Dark amber in color with a medium-sweet flavor, best as a dessert wine.
  • Malmsey – Dark amber and very sweet and intense, best as a dessert wine.

*A particular version of Verdelho Madeira that is a very popular aperitif wine is labeled: Rainwater.

Vin Doux Naturel

As noted in the Port section above, Vin Doux Naturels (VDN) are sweet dessert wines from France that are made in a similar process to Port. Like Port, extremely ripe grapes are fermented to a point where the residual sugar level is approximately 10%, when the fermentation is halted through the addition of neutral grape spirit, fortifying the wine to 18% to 21% alcohol by volume. VDN is made from both red and white grapes, primarily in the South of France. The white versions are typically made from the Muscat grape, while the red versions are typically made from Grenache.

Best Known White Vin Doux Naturel

  • Muscat de Beaume-de-Venise
  • Muscat de Frontignan
  • Muscat de Rivesaltes

Best Known Red Vin Doux Naturel

  • Banyuls
  • Maury
  • Rasteau
  • Rivesaltes

Next: Non-Fortified Dessert Wines >

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