Factors that Affect How Sweet a Wine Tastes

Last time, the topic of residual sugar was discussed.  Simply put, residual sugar (RS) is a measure of the sugar (typically in grams per liter) that remains in wine after fermentation.

During an uninterrupted fermentation, the yeast will continue to convert sugar to alcohol until nearly all the sugar is gone or the alcohol level reaches the point that the yeast can no longer live. But, if a wine maker decides to interrupt the fermentation, for example by lowering the temperature to the point where fermentation stops, they end up with wines having higher residual sugar.  That's one way to get a wine with higher residual sugar that tastes sweet.

In the case of sweet dessert wines, the grapes are either allowed to ripen to the point where they have very high sugar levels, dried to create a high sugar to water ratio (raisins) or, in the case of Ice Wine, the grapes are squeezed while frozen so the water does not get extracted and only a highly concentrated sugar solution results. In all these cases, fermentation starts with very high sugar levels so that upon completion of fermentation, there is a high amount of residual sugar.

Another way that wines can seem sweet has little to do with residual sugar.  Wines such as Gewürztraminer and Chenin Blanc are typically thought of as sweet wines.  But whereas a dry (very low RS) Cabernet Sauvignon or Zinfandel will have 0.5 to 1.0 grams per liter (g/L) of residual sugar, a Gewürztraminer can have as little as 1.5 g/L RS and a Chenin Blanc may have around 3.0 g/L RS.  To put this in perspective, a soda pop will typically have around 100 g/L RS!  So, yes, a Chenin Blanc may have twice the RS of a Cabernet, but it's tiny in comparison to a really sweet drink. So why are these wines often considered sweet?  Typically, it's because these wines have big, bright, bold fruit flavors and aromas that we associate with sweetness such as melon, apple, honey, rose, pineapple and grapefruit. Our nose 'fools' us into believing that the wine is sweet when it really doesn't have a significant sugar content.

On the other end of the spectrum are wines such as a sweet Riesling. These can have RS levels in the 40 g/L range. This is definitely sweeter.  One of the reasons that this sweetness is kept in-balance is by the high acidity of these grapes.  You've probably experienced this with lemonade and sodas such as colas which are very high in sugar (> 100 g/L RS) but also have very high acidity. The characteristics of sweetness and acidity balance each other out for a more enjoyable drink.

Another common wine that tends to be sweeter is White Zinfandel. It can have RS levels of 20-40 g/L.  Hence, it makes a great entry-level wine or just a sweet refreshing wine.

And, while we often think only of white wines and rosés as being the ones that can be sweet, even red wines can be a bit on the sweet side. Examples include common red wine blends found in grocery stores with brand names such as Apothic Red, Menage a Trois, Stella Rossa, Yellow Tail and Barefoot.  Even the very popular Meiomi Pinot Noir has 7 g/L of residual sugar.  Now you know why these brands are so popular!

As always, what's most important is that you drink what you like. And, if your taste buds steer you in the direction of sweetness, there are plenty of wines to explore and enjoy. Cheers!

What is Ice Wine?

Ice wine (eiswein in Austria and Germany, or the single-word icewine in Canada) is produced from the pressings of frozen grapes. 

Germany and Canada are the leading producers of traditional ice wines, but Austria, Switzerland and the United States also produce ice wine. 

Traditional ice wines are made by leaving grapes, such as Riesling, Gewürztraminer, Vidal Blanc, Sylvaner and even Cabernet Franc, on the vines until temperatures drop in the vineyard to well below freezing. In Germany, law states that the outside temperature must drop to 19.4˚F (-7˚C) or below, while Canadian law requires the temperature to 17.6˚F (-8˚C) or lower.

Grapes meant for use in producing ice wine dehydrate and concentrate during the winter, going well past their traditional harvest date. Once a deep freeze occurs, the frozen grapes are quickly harvested.

In some countries, such as the US and Canada, grapes are picked at their peak of ripeness and then put into freezers to yield frozen grapes. While this process is a lot more controlled than waiting, and hoping for a deep freeze, these wines cannot legally be called ice wine. Instead, they are often called iced wine or ice box wines.

Hydraulic pressure is then used to crush the grapes while still frozen, resulting in a very small amount of very concentrated sugary substance. Because the water is frozen solid, it is not extracted from the grape in the pressing process. This high sugar extract is then put through fermentation. With all the natural sugar, the fermentation process does convert some of the sugar to alcohol, but much of the sugar remains in the wine. This results in the very sweet ice wine that is bottled.

Ice wine ends up a golden or deep amber color with flavors of apricot, peach, mango, melon or other sweet fruits. And you may detect a nutty smell to it as well. The really nice ice wines tend to be expensive and therefore are commonly found in half-bottles. These wines are typically enjoyed as dessert wines and pair well with cheese.  If you get the opportunity, give one a try. Cheers!

Dessert Wines

In past entries we've explored fortified wines that are just one major category of dessert wines. While the list of dessert wines is too expansive to cover in one posting, we'll touch briefly on the categories of sparkling wines and the various types of Late Harvest wines.

As discussed in prior posting, sparkling wines can range from dry to sweet. Typically a wine labeled "Dry" will have little to no residual sugar (RS). But that's not true in sparkling wines. Sparkling wines on the sweeter side are called:

• Extra Dry has 12-20% residual sugar
• Dry has 17-35% residual sugar
• Demi Sec will have 35-50% residual sugar
• Doux (meaning 'sweet' in French) will have greater than 50% residual sugar

A few of the sweeter sparkling wines include Moscato d'Asti, Asti Spumante, Sparkling Gewürztraminer, Demi Sec, and Sparkling Rosé. Sparkling wines are fun and festive and will go well with most dessert courses.

The other major category of dessert wines is Late Harvest wines.  These wines can be broken down by the following production methods:

• Late Harvest of the Grapes: Simply put, the longer the grapes stays on the vine the more ripe they become and the more natural sugar they produce. During the fermentation process, the yeast is not able to convert all the natural sugar to alcohol thus resulting in a sweeter wine. Nearly any grape varietal can be used to produce a Late Harvest dessert wine. These tend to be very rich and fruity with notes of honey.
• Using Dried Grapes: A dried grape, or raisin, just tastes sweeter than a grape because the sugar is not diluted in water. Thus, using dried grapes can result in more sugar, less water. Here again, the yeast used to ferment the wine doesn't consume all the sugar before dying off resulting in a sweet wine. Grapes may be dried on the vine, on straw mats or while hanging on racks.
  • Greek Straw Wines
    • Vinsanto is made with high-acid white Assyrtiko grapes
    • Samos is a sweet wine made from Muscat grapes
    • Commandaria is a sweet wine from the Mavro grape
  • German Strohwein/Austrian Schilfwein - These are sweet wines made from Muscat and Zweigelt grapes in Austria and Germany.
  • French Vin de Paille - From the Jura region of France, these wines are produced using Chardonnay and the ancient white wine grape Savagnin.
  • Italian Passito - These wines are made with several different kinds of grapes, both white and red, but notably from the Moscato grape. These have a fruity bouquet and flavors of apricot and raisins.
  • Vin Santo - From Italy, this wine is produced from Trebbiano and Malvasia grapes. Includes nutty and date-like flavors. Commonly served with biscotti that may be dipped in the wine or eaten separately.
• Noble Rot:  The awful sounding name of this method occurs naturally in climates where there are cool damp mornings and warm dry afternoons.  This environment is where naturally occurring fungus, Botrytis, causes the grapes to shrivel on the vine, losing much of the water and leaving behind the extra concentrated sweet fruit. The 'rot' is entirely harmless and results in a highly sought-after style of wine. In Bordeaux, France, the Sauternes region is famous for its Noble Rot wines produced mostly from the Semillon grape.
• Ice Wine: This method allows the grapes to freeze on the vine, converting all the water within the grape to ice. When the grapes are immediately picked and crushed, the ice remains behind and only the sugary juice of the grape is collected. Only a fraction of this sweet juice is converted to alcohol during the fermentation process, thus creating a sweet wine.

So whether it is a fortified wine, a sparkling wine or a Late Harvest wine, there are many choices for dessert wines. A general rule for a dessert wine is that it should be sweeter than the food being served and slightly chilled. So keep these options in mind when choosing a dessert wine to go with your favorite dessert options.  But, as always, drink what you like and enjoy! Cheers!