What To Consider When Substituting Demerara Sugar With Granulated
Sugar substitutes can be a tricky thing, especially when it comes to all the variations of "raw" sugars like demerara. It seems like it should be simple enough, as sugar is one of the most basic ingredients in cooking; but then the cake you made with brown sugar instead of white turns out dense and soggy, and you realize not all sugars are going to do the job. This has only gotten more complicated as the old brown and white options on the shelf have expanded further to include new styles like turbinado and muscovado.
Demerara sugar is something that people would have been unfamiliar with a decade ago, but it's simply a coarser grain sugar that (to compound the confusion) can be easily mistaken for turbinado at first glance. According to The Spruce Eats, demerara and turbinado are not truly raw sugar; they are just slightly less processed than white or brown sugar. That different production method is what gives demerara its distinct characteristics, as it retains some small amount of molasses and gets filtered to a consistent size that's larger than your standard sugar crystal. All those differences mean substituting granulated sugar in its place will make a difference in your recipe.
Granulated sugar has a more neutral flavor than demerara
How demerara sugar will work in place of granulated depends on how you're using it. Kitchn states that white sugar and demerara can be swapped out for each other at a one-to-one ratio as they both provide the same level of sweetness. However, the molasses in demerara means it has a bit more of a caramel flavor than refined white sugar. According to MasterClass, white sugar provides a neutral sweet flavor, so if your recipe requires the flavor of demerara instead of just using it for sweetness, white, granulated sugar won't give you the same result. You can make up for the difference by adding a small amount of molasses to the recipe if you like. And the molasses in demerara does than more than bring flavor, it's also a source of moisture. Demerara doesn't contain as much molasses as light or dark brown sugar does, so white sugar won't affect the finished product as much, but it will make a difference. If you were going for a denser, chewy texture, granulated sugar could make it a little lighter.
The biggest difference between the two is if you are using demerara as finishing sugar, like on top of a muffin. This is one spot where granulated won't cut it, as it's just too fine to give you the same crunch. In most cases, you should have no problems swapping out demerara sugar for granulated, just be prepared for slightly different results.