Ever Wonder? What Makes Some Wines Sweet?

In wines, there is a wide spectrum of sweetness. Those that are not sweet are referred to as “dry” wines while those that are sweet are simple referred to as “sweet” wines. And, in the wine world, this all has to do with ‘residual sugar.’

When wine grapes are ready for harvest, one of the primary indicators to the winemakers is their sugar content. Using a device called a refractometer, they are able to analyze a drop of grape juice and determine its sugar content. By passing light through the juice and measuring the refraction (i.e., the amount that the light bends), the sugar content can be measured. This is referred to as Brix.

So, in simple terms, when the grapes are ready to be harvested they have ‘just the right amount’ of sugar. Anyone who’s had a glass of grape juice with breakfast knows that grape juice is naturally sweet. And, this natural sugar in the grape juice is the key to fermentation. Yeast is added to the grape juice and the live yeast feed on the sugar and converts it to alcohol. And, in general terms, once all the sugar is eaten up, fermentation ends.

But, wine makers have some control over this process. They can allow fermentation to go to the end which means that there is little to no ‘residual sugar’ in the juice that’s now wine. This is the ‘dry’ wine. But, if the fermentation is halted, or only a small amount of yeast is added to the juice, the wine ends up with significant ‘residual sugar.’ And, this results in a ‘sweet’ wine.

That’s a quick overview of sweetness in wine. For further reading, check out these past blogs:

Not All Rosé Wine is Sweet

I’ve heard it over and over - “I don’t drink rosé…it’s too sweet.” But, that’s not always the case.

Unfortunately, rosé wine’s reputations got ruined in the 1970s with wines such as Mateus, Lancers and especially White Zinfandel. Those are the stereotype rosé wines. And, yes, they were more like strawberry soda pop (hence its popularity). Not that there is anything wrong with strawberry soda or that style of white Zinfandel, it’s just that not all rosé wines are sweet. In fact, most bottles of rosé wine being sold today are not actually sweet.

While our brain naturally associates fruit aromas and flavors with sweetness, they are often not directly associated with each other when it comes to wine. Many rosé wines have aromas and flavors of tropical fruits (pineapple, mango) and red fruits (strawberries, cherries, cranberries, raspberries). These wine flavors and aromas may be processed and interpreted by your brain as being “sweet.” But, that doesn’t necessarily mean that it is sweet.

For a wine to be sweet, it must have sugar in it. In the wine world, it’s referred to as residual sugars (RS). That is, natural sugar from the grape’s juice that is not converted to alcohol during fermentation. But, most wines on the store shelf are “Dry” meaning they have a very small amount of residual sugar (1-10 g/L RS).

Today you can find a lot of very nice dry rosés being produced around the world. So try a dry rosé. They are actually not sweet. Cheers!

Ever Wonder? Can Aged Riesling Really Smell like Petrol?

Wines regularly get described by their aromas – floral, citrus, green apple, melon, herbal, cherry, plum and spice. But, Riesling – can it really including the aroma of petrol?

 A lot of people might assume a bottle of Riesling must have gone bad if they detect an aroma anything like petrol, gasoline or kerosene. But, this actually is a key characteristic of an aged Riesling!

 Not that a Riesling grape straight from the vine will have any such smell, but petrol is an aroma that forms during the fermentation process.

 There is a lot of chemistry that goes on during a wine’s fermentation. And, the development of exotic chemical compounds is one of these.

 As I started with, the fermentation of grapes can result in a tremendous range of aromas – most of which come from the chemical interactions of the juice of grapes and yeast. Other aromas can be introduced during the aging process (e.g., from oak barrels).

 It turns out that a petrol-like aroma is a natural occurrence in aged Riesling. Your glass of wine is not going to smell like a gas can, but there can be “delicate” aromas of petrol.

 Without getting into the chemistry details, the reason that an aged Riesling can smells like gasoline is due to a chemical compound called TDN (1,1,6-trimethyl-1,2-dihydronaphthalene). While the potential for TDN to be produced and noticed in most wines is pretty low, Riesling grapes have the highest chance to exhibit this distinctive aroma. Don’t lose sight of the fact that the primary aromas of Riesling will be tropical fruit, red fruit, melon, citrus and spice. But, there can be this petrol-like aroma compound. And, in combination with the other aromas, it can also result in aromas of honey, beeswax or paraffin.

Sources: GL Sacks et. al. (2012), C Black et. at. (2012)

So, try an aged bottle of Riesling. Not that petrol is an aroma you may desire, but open up mind and your nostrils and see if you can pick out the aroma. It’s not for everyone, but it’s certainly worth trying as you continue on your wine journey. Cheers!

Other Factors that Affect How a Wine Tastes

Last time we explored how terroir (the soil, terrain and climate) can affect how a single varietal of wine tastes. But, there are a host of other things that can also affect a single varietal’s taste, aroma and overall flavor.

Harvest

Maceration

Fermentation

Malolactic Conversion

Blending of Grapes in a Single Varietal

Aging

Serving Temperature

Serving Vessel

This is just a brief outline of some of the factors that can affect a single varietal’s flavor. But, there are even more! And we’ll explore those in future blogs. Cheers!

Confusing Sweetness and Fruitiness in Wine

Many wine drinkers may confuse the taste sensations of sweet and fruity. While our brain naturally associates fruit aromas and flavors with sweetness, they are often not directly associated with each other when it comes to wine.

“Fruity” is a term that gets used to describe a wine that has pronounced flavors or aromas of fruits. With wines, you may experience aromas and flavors of citrus (lemon, lime, orange), orchard fruits (apples, pears), stone fruits (apricots, peaches, plums), tropical fruits (pineapple, mango), red fruits (strawberries, cherries, cranberries, raspberries), or dark fruits (blackberries, blueberries, black currant). These wine flavors and aromas may be processed and interpreted as being “sweet.” But, fruity wines aren’t necessarily sweet. Sauvignon Blanc is a good example. While it offers bright fruit flavors of grapefruit, lime, pear and peach, it is typically low in residual sugar.

For a wine to be sweet, it must have residual sugars (RS). That is, sugar that is intentionally left in the juice that doesn’t get converted to alcohol during fermentation. The categories of wine sweetness include “Dry” (1-10 g/L RS), “Off Dry” (10-35 g/L RS), “Sweet” (35-120 g/L RS) and “Very Sweet” (120+ g/L RS).

Most wines on the store shelf are “Dry” but if you’re looking for sweeter white wines look for Kabinett or Spätlese Riesling, Chenin Blanc or Gewürztraminer. Lambrusco is a sweeter, sparkling red wine. Sweeter red wines, by brand, include Ménage á Trois Red (12 g/L RS), Apothic Red (15 g/L RS), Cocobon Red Blend (12 g/L RS), Yellow Tail Shiraz (12 g/L RS) and Jam Jar (57 g/L RS).

So, don’t be fooled. “Fruity” wine traits don’t necessarily mean it’s a sweet wine. Cheers!