Josh Talks: How Dessert Wine Is Made: From Eiswein to Sauternes

So we're talking about winemaking and today we're going to focus on sweet winemaking. It's a little different than making dry wine. You know we all think about, you know, all us wine lovers think about wine. We're pretty much thinking about a dry wine, something we're going to have with a meal. But there are a lot of sweet wines and what's maybe interesting about sweet wines is, you know, you think about sweet beverages, soda, iced tea, you're adding sugar basically to make them sweet. But with wine the sugar is already there in the grapes, right? So how do you make a wine and keep that sugar in the wine because the yeasts are eating up the sugar and turning it into alcohol? Well there's a couple ways you do it and probably the most common way is to interrupt the fermentation. So you've got your grape juice, it's fermenting away and you reach a certain level of alcohol where you still have sugar in your juice. And this leftover sugar, by the way, is known as residual sugar or RS. That's a term you're going to hear a lot in the wine world. So you've got your residual sugar, you've got your level of alcohol and then you decide, well this is where we want to be in terms of, you know, the sweetness level and the balance. And so you stop the fermentation a couple of ways. A real common way to do it is to just chill it down because the yeasts stop functioning when they get too cold. So you chill it down to about 45-50 degrees and then the yeasts stop fermenting. So then you just have to filter the wine, you know, you do a sterile filtration, remove all the yeast and you have your sweet wine. The other way to do it is you can add sulfur and sulfur can kill the yeasts. And for the most part that's as effective. Sometimes it's less effective depending on the yeasts and sometimes it's not as advantageous because maybe you don't want to add so much sulfur to the wine. But those two methods are fairly common. You know, the other one that is also used for stopping fermentation is adding alcohol because alcohol will kill the yeasts. And that's generally how fermentation stops, right? You make a dry wine, you have grapes with a certain amount of sugar, the yeasts come along, they eat up that sugar, they spit out their alcohol and their CO2 to the point where it reaches about, what, 14 percent alcohol and then the alcohol level is so high that the yeasts die off. And then you have, but you have a dry wine because they've basically, they've eaten up all the sugar. You can make a sweet wine that way by adding alcohol. So for instance, there's a wine called Muscat de Beaume de Venise. You take these wonderful sweet muscat grapes, you start the fermentation, you let it go a certain length until you've got, you've still got some nice residual sugar left and then you add grape brandy generally. And it kicks up the alcohol level, kills off the yeasts, and so you've got a kind of like a wine with sort of a dry wine alcohol level, maybe 14 percent. But it's got that residual sugar, so it's sort of nice and sweet and it's, you know, it really makes something that's fun to drink. So those are a couple ways. Then there's the other way, which is where you have your grapes be super, super concentrated with sugar so that there's so much sugar that when the fermentation takes place, even if that fermentation keeps going, keeps going, you get to that 14, 15 percent alcohol and there's still more sugar, but those yeasts die off. That's generally how Sauternes is made or these sweet German wines like Barnauslaser, Trockenbarnauslaser. The grapes stay on the vine until they get really overripe and sometimes they're going to start to shrivel up and then and the sugar is very concentrated in these grapes. So the fermentation can carry on just like it would in a dry wine, but once it stops, you still have a very sweet wine at the finish. Then there's the other very unique one and that's ice wine. I'm sure you've heard of ice wine. Well, ice wine, it's a similar situation in that you have very sweet grapes, but what you'll have with ice wine is they're frozen, right? So you leave these grapes on the vine until they get really overripe and then you leave them on even longer until the weather turns and the grapes actually freeze on the vine. So you bring in the frozen grapes, you press the frozen grapes, and you get a really sweet syrup coming out of these frozen grapes. And again, this concentrated syrup, it's going to ferment with the yeast until those yeasts are finished because the wine reached a certain alcohol level, but you still have a lot of sweetness left in that wine. These wines, depending on how they're making them and what kind of grapes they're using and a lot of different factors certainly, but balance is very important that that sweetness balances with the alcohol, that balances with the nice acidity in the wine. But yeah, those are the ways that you can make sweet wine. There may be another one or two, but those are the primary ways. So a little different than dry wines, but at the same time, it can be the same depending on, you know, what kind of grapes you're using, right? Okay, that's what we got today.