Exploring how sweet wines are made.
We're back to tackle another question in our Ask The Expert series! In this edition, we explore how a winemaker produces a sweet wine - or conversely, a dry one. Whatever you prefer, whether bone dry or those that are sickly sweet, Winemaker Hal Landvoigt of Lunar Harvest breaks down how it happens!
Here is Hal's fascinating answer to the question: Why Are Some Wines So Sweet?
Wines can range from sweet to dry for a number of different factors. When we harvest grapes, we make a conscious decision to pick the grapes based on how ripe the grapes are and how mature (the balance between the sugar and the acid in the grape) they are. Generally, the longer we allow the grapes to hang on the vine, the higher the concentration of sugar in the grapes. With some wines, they are further allowed to dehydrate on the vine, like in a Late Harvest Riesling, or even by allowing the grapes to freeze so that when we press them, a portion of the water in the grapes is not pressed out because it is frozen as ice. This is where we get the term Ice Wine from.
Grapes with more sugar (higher brix, is the technical phrase) have the potential to make sweeter wines or to make higher alcohol wines. When we take the juice from the grapes and add yeast to convert the juice into alcohol, the yeast consumes the sugar and produces alcohol as the byproduct. This is true for all yeast used to make alcoholic beverages, whether it is beer, wine, cider, or even whiskey and vodka – yeast consumes the sugar and produces alcohol.
When the juice is fermenting, we then make a second decision about when to stop the fermentation. In a Riesling, for instance, if we allow the yeast to consume all the sugar in the juice, it produces a dry wine – meaning it has very little sugar in it. It would be a dry Riesling. If we stop the fermentation before all the sugar has been consumed, we end up with a wine that has residual sugar (sweetness). In the world of Riesling, you can end up with great variability typically ranging in four categories: dry, medium dry, medium sweet and sweet - which encompasses late harvest and ice wines. Lunar Harvest Riesling for example, has 1.9% residual sugar which puts it at a medium sweet level.
How do we do this? We stop the fermentation, either by adding Sulfur Dioxide (SO2) which inhibits the yeast's activity, or we run the wine through a centrifuge and "spin" the yeast out of the wine. In some situations, we may add sweetness back to the wine either with very sweet grape juice. This is done to balance out the acid in the wine, add richness (viscosity) or to bring out a more fruity expression in the wine.
Thanks to Winemaker Hal Landvoigt of Lunar Harvest for his answer to the question Why Are Some Wines So Sweet?
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