What is Residual Sugar?

We’ll do our best to keep this post short and sweet.

(Get it??…sweet?)

Last time you did a wine tasting, you may have heard your server say something like, “This wine has 3.5 percent RS.” Not everyone knows this wine jargon, and its purpose in winemaking is oftentimes misunderstood. Here are a few things about residual sugar that you may not know:

RS stands for Residual Sugar. Residual sugar consists mostly of the grape sugars that are left over after the fermentation process but can also be created by small amounts added before bottling.
Residual sugar is usually a natural by-product of grape fermentation (when grape juice is crafted into yummy wine) and is preferably not something added to wine to make it sweeter.
All of our Arcturos wines are made in the process described here and will only contain a residual amount of sweetness “held-over” from the fermentation process. This is usually done by chilling the wine to a temperature close to 30 degrees Fahrenheit, to halt any yeast activity. Some of our other wines, such as the Red House series, MAY contain a small amount of sugar that was added before bottling if the winemaker felt this best served the style of the wine.

Example of someone performing a punch down during the fermentation stage of wine making.

Wine grape juice is VERY sweet and varies based on the variety. To control the sweetness in wine during the fermentation process, grape sugars are converted into alcohol with the introduction of yeast strains. Here is a simple formula to illustrate this process.

Sugar (as grape juice) + Yeast = Alcohol + CO2
Pretty simple, right?

So how does residual sugar relate to Black Star Farms wines? Our wines range from 0% RS up to 14% RS. You can find residual sugar content information on each of our products when you shop online. Choose the product you’d like to view and scroll down the page a bit. The residual sugar percentage is displayed in the summary tab on the product page.

For example, if the 2017 Arcturos Dry Riesling has an RS of .55%, that means for every 5-ounce serving, residual sugar makes up 00.55% of that serving (this is a really small amount of sugar – approximately 1/10th of 1 gram!).

Award-winning 2017 Arcturos Dry Riesling with many medals.

On the opposite side of the spectrum, the Sirius Raspberry Dessert Wine has an RS of 14%. This means a 2-ounce serving would contain 14% RS (or approximately 9 grams of sugar), which would be considered quite high. This higher sugar is present to balance the high acid of the raspberry fruit and the alcohol level created during fortification. In this case, the residual sugar and alcohol level (17%) stabilize the wine for decades of aging and create a rich and delicious wine. We recommend enjoying 2-3 ounces in a small flute alongside something sweet like cheesecake or chocolate.

Sirius Raspberry paired with chocolate at the tasting room at Black Star Farms Old Mission.

You’ll find Black Star Farms wines are all over the sweetness spectrum with many options for every taste. Scroll through our products online and find those bottles that speak to you, or give us a call if you need more information. Our free shipping on 6 or more bottles promotion is still in full swing for those of you hoping to stock your wine shelf. No coupon code is needed.

Cheers, and stay safe!

About the Writer, Olivia Kiel

As a Manager at the Old Mission Peninsula Tasting Room and blogger for Black Star Farms, I get the opportunity to write and learn about wine (two of my favorite things) every day. Over the years I’ve developed a passion for everything Black Star Farms by working alongside the company’s best and pouring its finest wines for guests from all over the world. I have a Bachelor of Science degree from Ferris State University where I studied Writing and Business and have been a Northern Michigan resident for about three years. When I’m not pouring wine, you’ll likely find me with a good book, enjoying the outdoors, or tasting something new and exciting at a local winery. Thank you for reading my posts, and don’t hesitate to say hello next time you visit Black Star Farms Old Mission. Cheers!