Wine 101: Navigating sweetness in white wines

If there’s one thing we know to be true in this industry, it’s that wine is tricky. Identifying all the nuanced aromas, understanding the intricacies of production, getting through all those dubious tasting notes (freshly opened tennis balls, anyone?) – it's hard work. And you’d think a question as simple as ‘is this wine sweet?’ would be easy enough to answer. Wrong! Sometimes wine with the highest sugar can actually taste dry, while those with less sugar can taste sweet. Huh?! Wine, we need a word.

We’ve done a little sampler of how this all works in red wine, but here, we’re doubling down on whites – riesling and pinot gris and grigio, we’re looking at you. So, let’s get stuck into it.

As mentioned, wine is a bit of a trickster, but we can’t blame it all on the liquor – our tastebuds often do us dirty, too. What does this mean? Well, for example, if we’re told that a wine tastes like passionfruit, when we drink it, we will taste passionfruit. What's this got to do with sweetness? Passionfruit is inherently sweet, so our naughty brain does this cute thing where it’s like, “Ah, that’s passionfruit for sure, what I’m drinking must be sweet”. In reality, however, the wine we’re drinking may taste of passionfruit, but it may not be that sweet at all (this happens with spirits like Scotch, too, which can have notes like caramel, chocolate and molasses). This isn’t always the case, but it’s good to keep in mind. 

If your tastebuds are acting up, another quick way to tell if the wine is sweet is to swirl it in the glass before tasting it. If the liquid runs down the glass slowly and thickly (leaving what’s known as ‘legs’ inside the glass), it means it has a higher viscosity – and also often a higher alcohol content – so it is probably sweeter. Sorry if we scared you with a bit of neuroscience there, but if a wine is well and truly sweet, you can usually tell. It’ll hit you on the tip of the tongue with a little razzle dazzle or, as the wine nerds say, a “tingle”.

You’d think because white wine comes from grapes, it’d all be sorts of sweet. In reality, whites vary a lot – even in their own varieties – with some of the best examples being pinot gris and grigio, and riesling. But why such a difference? Well, there are many reasons – it can come down to when the grapes are picked (the later, the more sugar, as in the case of dessert wines), fermentation methods, higher alcohol content, and even added sugar in the winemaking process. But it’s mostly to do with residual sugar.

What is residual sugar, you ask? It’s the natural sugar left over from the fermentation process. When the grapes are fermenting, the added yeast chows down on the sugar. The point when winemakers put the brakes on fermentation (or god forbid when the yeast gets tired and calls it quits), is what determines how sweet or dry the wine will be.

Let’s take the profoundly delicious riesling as an example. Riesling is sometimes described as a wine that’s not totally dry and referred to as “off-dry”, which means it has some sugar to it, even if it tastes drier than you expect. Confused? We don’t blame you. Riesling, unlike other white grapes, has a large amount of acid, which can be overwhelming, so to balance that acidity, winemakers will purposefully stop the fermentation process to keep some of that residual sugar in the wine. However, that doesn't mean that all riesling is sweet (though some are) – it just means there’s more natural sugars in it than other “sweeter” tasting wines. If they kept the fermentation process going and that yeast chomped up all the remaining sugars, that wine would be so acidic it’d cut your mouth up. 

Again, why purposefully stop fermentation? Well, for balance, as we’ve discussed above, or to give the wine a natural sweetness that we see in other styles like prosecco or port (via fortification, but that’s a whole other thing –  you can read up on that here).

If a wine is bone dry, it means there’s barely any residual sugar in the bottle (less than 1% sweetness). So, starting with a bone-dry muscadet, sweetness (mostly) rises through into your sauv blanc and pinot gris, then chardonnay, chenin blanc and viognier. 

Off-dry means there is a little sweetness in the drop – around 3% or more sweetness. Gewürztraminer and riesling live comfortably in this percentage, but remember, while they may not taste overly sweet, their residual sugar is balancing a lot of acidity. Anything above 5% sweetness, you can taste. Moscato is the best example of this style, and if you’ve ever had one, you’ll  know what we’re talking about. When sweetness is in the 7 to 9% range, it’s dessert wine territory – we’re talking late-harvest rieslings and semillons, and fortifieds like white ports and tawnies.