Light vs. dark brown sugar: What's the difference?
And can I substitute one brown sugar for another?

Before we break down the difference between light and dark brown sugar, let’s review what brown sugar is. Originally, it was sugar that retained some of the natural molasses found in sugar cane juice even after processing — unlike white granulated sugar, in which all of the molasses has been removed.
Today, though, the brown sugar you commonly buy is just white granulated sugar with molasses added back in — up to 10% molasses, by weight. (That’s why you can easily make your own brown sugar substitute by combining white sugar with a small amount of molasses.)
The difference between light and dark brown sugar comes down to the amount of molasses it contains.
Dark brown sugar has a higher amount — about 6.5% — while light brown sugar hovers around 3.5%. That difference means that dark brown sugar (true to its name!) has a darker appearance and more assertive flavor, while light brown sugar is milder in both look and taste.
Yes. Though they differ slightly in color and flavor, that difference won’t be obvious in your baked goods. Neither will the small difference in acidity (as molasses is an acidic ingredient, and thus can impact how your leaveners perform). They also weigh the same, so you can interchange them whether you’re baking by weight or volume.
If your recipe specifically calls for “light” or “dark” brown sugar, you should use that type if you can. But if you only have one type of brown sugar on hand, go ahead and proceed with the recipe. And if your recipe just calls for “brown sugar” without specifying, feel free to use either.
Looking for recipes that call for brown sugar? Try Brown Sugar Sour Cream Pound Cake, Old-Fashioned Apple Cake with Brown Sugar Frosting, and Giant Brown Sugar Cinnamon Pop Tart.
Cover photo by Patrick Marinello; food styling by Lydia Fournier.
February 26, 2025 at 10:10pm
I’ve been going to “King Arthur” for my baking supplies for several years..both directly on line and in retail stores. I’ve never been dissatisfied.
Keep up the great work!
February 4, 2025 at 10:04am
I guess "super tasters" can tell the difference. I'm not one on them : )
Was there a time when molasses was stronger thus a difference between dark and light?
Or is this mainly a way to get shelf space at the store?
March 24, 2025 at 9:52am
In reply to I guess "super tasters" can… by JohnD (not verified)
Hi John, molasses still comes in stronger and milder varieties, as described in this blog post. However, I suspect the difference in dark or light brown sugar has generally been a matter of quantity. Note that in other varieties of brown sugar (muscavado), the sugar is only partially refined and the molasses that is a byproduct of sugar production is retained rather than added in.
January 29, 2025 at 9:26pm
How much molasses do you add to white sugar to get brown?
March 5, 2025 at 1:49pm
In reply to How much molasses do you add… by Pat (not verified)
Hi Pat, to make light brown sugar you will want to add 2 teaspoons of molasses for every 1 cup of granulated sugar. To make dark brown sugar, you should add 1 tablespoon of molasses for every 1 cup of granulated sugar. Hope this helps!
January 24, 2025 at 2:48pm
Some recipes specify packed brown sugar. Others do not mention packing the sugar into whatever measuring cup is used. Should brown sugar always be packed, or only if the recipe says so?
March 13, 2025 at 3:49pm
In reply to Some recipes specify packed… by Heather (not verified)
It will depend on who wrote the recipe, Heather. We recommend always using a scale when measuring out ingredients if the weight of the ingredients is listed in the recipe (a gram of sugar is a gram of sugar whether it is packed or not).