The difference is purely physical, not chemical. Both are made from sucrose, so your body processes them the same tragic way (hello, energy crash). But the smaller crystals in caster sugar dissolve much faster. That’s the secret weapon for angel food cake and meringues—you need that sugar to disappear into your egg whites before your arm falls off whisking.
Ever made a cocktail and felt that grainy grittiness on your tongue? That’s granulated sugar being a stubborn jerk. Caster sugar slips into your drink like a spy, dissolving before you even notice. Fun fact: bartenders often use caster sugar for cold drinks because it doesn’t require two hours of aggressive stirring to actually incorporate.
Can You Cheat? (And Not Ruin a Recipe?)
Yes, you can cheat, but you have to be smart about it. If you’re making cookies or dense cakes, swapping granulated for caster is fine—just slightly chewier. But if you’re making a sponge cake or a soufflé, using granulated is like trying to run a marathon in dress shoes. It works, but you’ll suffer.
The sneaky fix: grab your food processor, dump in granulated sugar, and pulse it for 10–15 seconds. Boom—you’ve just created DIY caster sugar. Just don’t go full speed, or you’ll end up with powdered sugar and a cloud of sweet dust that makes you look like a Victorian ghost.
