So here are five things to know about sugar and wine. I hope they will help you appreciate rather than fear a touch of sweetness in your glass.
Sugar is indispensable to wine. Vintners spend the entire growing season coaxing grapes to ripeness, trying to optimize their sugar content. Brix — a measurement of sugar in grapes — used to be the primary factor in a winemaker’s decision to harvest. Today, they also look at the color of the seeds and texture and flavor of the skins to determine ripeness, but sugar remains the most important factor.
And, of course, sugar provides food for the yeast to ferment into alcohol. A finished wine is considered bone dry if it has less than 2 grams of sugar per liter remaining after fermentation. This is called “residual sugar,” or RS. Most wines are dry, especially reds. Higher levels of RS classify a wine as medium-dry or medium-sweet. More than 45 grams per liter is considered sweet.
Wines can be enhanced with added sugar. Chaptalization is a process common for centuries, in which sugar or grape concentrate was added to fermenting grape must to boost the alcohol level in the finished wine. This used to be most prevalent in northern climes where it was difficult to ripen grapes consistently. It’s less common today, because improved viticulture helps wine growers get the grapes ripe and climate change is giving us warmer vintages.
Grape concentrate remains a common ingredient in industrial wine, which is made inexpensively in large quantities to fill shelves in supermarkets and convenience stores, especially in the popular “red blends” category. (Another pro tip: For a real red blend, look to Bordeaux.) Adding concentrate can mask shortcuts taken in the vineyard, making consistent wine from inferior grapes. You may hear wine geeks mention Mega Purple, a popular concentrate made from ruby cabernet, a workhorse grape known more for color than flavor. If your inexpensive red is intensely purple and tastes thick and sweet, that might be Mega Purple. We don’t really know, however, because wineries are not required to tell us what concentrates or other additives they use in their wines. Made from grapes, grape concentrates are a relatively benign additive, but if you taste enough wines, you can identify ones that are manipulated or enhanced with them.
Even dry wines can have “sweet” flavors. Ripe fruit tastes sweet. When I recommend wines, I try to avoid describing them as “sweet,” preferring “sweet flavors” or “ripe peaches” and such. Wines with higher alcohol levels can also taste sweet, as the glycerin in alcohol gives a perception of sweetness. Alcohol is fermented sugar, after all.
As in yoga, balance is key. Riesling can be glorious at any point on the dry-to-sweet spectrum, but it remains the world’s most underrated wine because consumers fear the sweetness. The best rieslings maintain a keen balance between residual sugar and acidity that makes the word “sweet” almost irrelevant. A group called the International Riesling Foundation has developed a sweetness scale based on a wine’s sugar and acid content. This scale on a label helps us know what we are buying before we pull the cork. But some wineries are reluctant to put the scale on their labels, fearing any marker on the sweet side of dry will actually hurt sales.
Chenin blanc is another white grape that makes fantastic wines, dry or sweet. Wines from Vouvray in France’s Loire Valley do not always indicate their dryness level. South Africa’s chenins, however, are typically dry or slyly off-dry, balanced so you won’t notice any residual sugar as sweetness.
Virginia’s winemakers are zeroing in on an ideal sugar-acid balance for petit manseng, a white grape high in acid and sugar that is rivaling viognier as the commonwealth’s signature wine. The bull’s eye appears to be just off-dry, but you could spend a delicious wine-geeky weekend comparing several labels. (My shortlist: Michael Shaps, Horton Vineyards, Early Mountain Vineyards, Hark Vineyards, Glen Manor Vineyards and Granite Heights.)
A truly sweet wine can be divine. Sauternes. Vendange tardive. Vin Doux Naturel. Trockenbeerenauslese. Ice wine. Tokaji. Port. Madeira. Pedro Ximénez sherry. These names get wine lovers salivating, even if we don’t drink them often enough. I was recently privileged to share a 1920 Malvasia Madeira with friends after a blowout dinner. The wine made a special evening truly memorable. Even less rarefied stickies can put a satisfying coda on any occasion. Now, that’s sweet.
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