It’s hard to pinpoint when popular opinion declared that good wines must be dry, but it couldn’t be farther from the truth. Whether it was the recent rosé revival that taught us to value dryness in response to the bulk blush wine of a bygone era, or bad experiences with cheap, sweet alcohol, most aficionados today choose dry wines.
However, sweet wines are made from some of the most regulated, carefully observed grapes, and they represent terroir and tradition as fiercely as any dry offering.
Consider the rigorous German Prädikatswein system, which ranks top grapes from specific regions based on their ripeness at harvest. Or there’s the serious manner by which a Port producer assesses the year’s conditions and the resulting young wine before it declares a vintage. The prediction determines if a given bottling is worth decades of guarding, and at stake is nothing less than the producer’s reputation.
An artfully made sweet wine is a labor-consuming effort with risk at every turn.
When is a wine sweet?
Whether a wine is “sweet”, isn’t such a straightforward question. But a glance at the alcohol by volume (abv) can provide a clue.
Many dry wines register at more than 14% abv. Finding alcohol below 10% on a bottle generally indicates a sweet wine, as is common with Kabinett Riesling or Moscato d’Asti. Although the category of “dessert wine” persists on wine lists and elsewhere, understanding which dessert wines are technically sweet, and to what degree, is critical to understanding and appreciating them.
How sweetness in wine is measured
The sweetness of a wine is spoken about in terms of residual sugar, measured in grams of sugar per liter, that remain in the finished wine. Wines considered dry have no perceptible residual sugar, and are typically fermented to 0–3 grams per liter, though many wines that pass as dry can contain up to 8–10 grams, or about 2 ½ teaspoons, per liter. The perception of sweetness varies depending on a number of factors, from the grapes’ natural acid to the winemaker's technique.
In addition to the taste on our palate, the presence of sugar adds perceptible weight to the wine and changes its texture. This can manifest as a touch of voluptuousness, in the case of a still Vouvray, Rhône white, or the dense syrup of aged Pedro Ximénez.
To leave some residual sugar in a wine also balances high-acid grapes, a surprisingly common technique, but these wines are still classified as dry. Though there’s no obligation to, most producers will indicate on the label if the product veers into the vague territory of off-dry, or slightly sweet, wine. In a sparkling wine, this can be labeled “extra-dry,” to the confusion of many.
Sweet wines are best made from grapes with a high acid content. Acid structures what can otherwise be a bland sweetness, while residual sugar makes acidic flavors and aromas more palatable.
Even in the sweetest wines, the role of acid cannot be overemphasized.
What are the different types of sweet wine?
How a wine was made can predict the sweetness of the final bottling. Sweet wines are either fermented directly from grapes with concentrated juice, like with late-harvest wines, or by halting an ongoing fermentation with alcohol, temperature or sulfites, or in some cases, adding a sweetening agent after fermentation. They can be made from any variety in a location suitable for growing.
Late-harvest grapes
Unfortified wines, sometimes called “naturally sweet,” come from grapes that have been concentrated in some way. This could mean grapes harvested late in the season, a style common to cooler climates. It can also be achieved from a period of drying after harvest, or inoculating the fruit with fungus like Botrytis cinerea, aka “noble rot.”
Whatever the technique, the goal is to reduce water content, which amplifies the grape’s remaining sugar, acid and flavor. The more water you let dry out, the more intense the wine.
Passito
Some grapes are picked at harvest time, but left to dry, typically on mats, from a few weeks to a few months. This ensures high acidity and supervised drying. In Italy, this style of winemaking is called passito. It’s used to make both dry and sweet Amarone, as well as Vin Santo, the sweet wine most associated with the country.
Other styles simply demand waiting until all berries on the vine resemble raisins, at which point, they’re picked meticulously by hand and pressed.
Waiting for grapes to get to this state is tricky. If rain and hail aren’t a threat, there’s always the risk of unfriendly rot, or even birds that will eat your crop. In wineries where sweet wine is not the lone style produced, vintners often must weigh potential losses when they decide whether to create a sweet or dry wine.
When sugar levels get too high, it also inhibits the yeast. In basic fermentation, yeast consumes sugar to produce alcohol and carbon dioxide. When there’s too much sugar, the yeast becomes overnourished and can’t do its job, creating another potential risk when producing wines in this style.
Botrytized wines
Wines made from grapes infected by noble rot, or Botrytis cinerea, are among the most famous and expensive in the world. This method was said to be first practiced in the Tokaj region of Hungary before it spread to Germany and France, though it’s limited to regions where the climate and fog can trigger the rot. These wines can only be made during the best vintages, and noble rot is not always guaranteed to take hold on the crop.
Ice wine
Ice wine is a method where grapes are picked when the weather becomes cold enough for them to freeze. The grapes must also be pressed while frozen. This yields a more concentrated juice by leaving much of the water behind, still frozen in the grape. This method originated in Germany, where it’s called eiswein. It’s also become particularly popular in Ontario, where it’s trademarked as icewine, generally made from Riesling, Vidal Blanc, and even a unique red variation based on Cabernet Franc.
Fortified sweet wine
Since yeast dies at alcohol levels greater than 18%, fortifying a wine to that degree, or higher, is an effective way to stop fermentation and retain any leftover sugar. Wines like Port, Madeira, and France’s vin doux naturel (VDN) are all produced this way. An entry-level bottle produced in this style typically costs less than a naturally sweet wine.
One technique to create fortified wine is by using a mutage, or unfermented grape juice, blended with a neutral spirit, and mixing it with the fermenting wine, in order to raise alcohol levels and stop the yeast. Mutage can even be consumed on its own, often with brandy being used as a base, more commonly called mistelle. While not technically a wine, mistelle can have similar aging potential and drink like a fortified wine.
How long can sweet wines age?
Sweet and fortified wines are some of the safest bets for long-term aging. Produced with an emphasis on acidity and added preservation power in the form of high sugar and sometimes alcohol, these wines are famous for their longevity.
Vintage Port is meant to be aged for at least 15 years, although multiple decades are preferred. The same applies to quality Madeira, the cooked wine said to last forever. Tokaj and Sauternes are unfortified wines that can be aged for decades, which has led to record-breaking prices at auction for antique bottles.
As these bottles age, the sweetness does not disappear, but the wine picks up darker flavors. It strikes a better balance on what may have tasted like simple sugar when the wine was young.
