Best Substitutes for Caster Sugar
Caster sugar is refined white sugar ground to a finer consistency than regular granulated sugar. The crystals are about half the size of granulated sugar crystals, which means it dissolves faster and incorporates more easily into batters and doughs. This makes it particularly valuable in meringues, where undissolved sugar crystals create a gritty texture, and in delicate sponge cakes where you need quick dissolution. The fine texture also helps create smoother buttercreams and more tender baked goods. Caster sugar has the same sweetness level as granulated sugar (99.9% sucrose), so the main difference is physical, not chemical. When substituting, you're primarily matching the dissolving speed and crystal size rather than flavor or sweetness intensity.
Best Overall Substitute
Granulated sugar processed in a food processor for 30-60 seconds. This creates the exact same crystal size as store-bought caster sugar at a 1:1 ratio. The processing breaks down the larger crystals without creating powder, giving you the fast-dissolving properties you need.
All Substitutes
Granulated sugar (processed)
1:1Pulse granulated sugar in a food processor for 30-60 seconds until the crystals look finer but haven't turned to powder. This creates the same crystal size as caster sugar. Works identically in all recipes because you're not changing the chemical composition, just the physical structure. The finer crystals dissolve faster in batters and cream more easily with butter. Stop processing before it becomes powdered sugar.
Superfine sugar
1:1Superfine sugar is the American equivalent of caster sugar, with crystals ground to the same size. Works identically in all applications because it's essentially the same product with different regional naming. The dissolution rate and incorporation properties match exactly. No adjustments needed to recipes, timing, or technique. Look for it in the baking aisle of most supermarkets.
Honey
3/4 cup honey per 1 cup caster sugarHoney is 80% sugar and 20% water, so you need less volume but must account for the extra liquid. Reduce other liquids in the recipe by 1/4 cup for every 3/4 cup of honey used. Lower oven temperature by 25F because honey browns faster than sugar. Adds floral notes and creates moister, denser baked goods. The acidity in honey (pH 3.9) can affect leavening, so add 1/4 teaspoon baking soda per cup of honey to neutralize.
Coconut sugar
1:1Coconut sugar has larger crystals than caster sugar but similar sweetness (about 75% sucrose). The crystals don't dissolve as quickly, so cream butter and coconut sugar for an extra 2-3 minutes to ensure proper incorporation. Adds subtle caramel notes and light brown color to finished products. Contains trace minerals that don't affect baking performance. Works best in recipes where the slight color change and flavor addition are acceptable.
Light brown sugar
1:1Light brown sugar is granulated sugar with 3.5% molasses added, creating slightly larger, more moist crystals. The molasses adds subtle caramel flavor and produces more tender, chewy textures in baked goods. The extra moisture (about 2% more than white sugar) can make batters slightly wetter. Pack it firmly when measuring to ensure accurate ratios. The molasses also acts as a mild acid, which can enhance leavening.
Demerara sugar
1:1Demerara has larger, crunchier crystals than caster sugar and retains natural molasses, giving it a light amber color and mild toffee flavor. The crystals take longer to dissolve, so increase creaming time by 3-4 minutes when making buttercream or cookie dough. Creates slightly coarser textures in delicate baked goods. The molasses content (about 2%) adds moisture and enhances browning. Works well where a subtle crunch is acceptable.
How to Adjust Your Recipe
When using processed granulated sugar, no changes needed. For liquid sweeteners like honey, reduce other liquids by 1/4 cup per 3/4 cup honey used and lower oven temperature by 25F. With coconut or brown sugars, increase creaming time with butter by 2-3 minutes to ensure proper incorporation since the crystals are larger. For meringues specifically, only use caster sugar, superfine sugar, or processed granulated sugar since larger crystals won't dissolve completely and create grittiness.
When Not to Substitute
Never substitute in meringues unless using superfine sugar or processed granulated sugar. The undissolved crystals from regular granulated or brown sugars create an unpleasant grainy texture. Avoid liquid sweeteners in recipes that depend on sugar's structure for texture, like shortbread cookies or sugar cookies. Hard candy recipes require the precise crystal structure of granulated or caster sugar to set properly.
Frequently Asked Questions
Can I make caster sugar from granulated sugar?
Yes. Pulse 1 cup granulated sugar in a food processor for 30-60 seconds until crystals are finer but not powdered. This creates identical results to store-bought caster sugar at a 1:1 ratio. Don't over-process or you'll get powdered sugar, which behaves differently in recipes.
What's the difference between caster sugar and powdered sugar?
Caster sugar has fine but distinct crystals that dissolve quickly. Powdered sugar is ground to powder with 3% cornstarch added to prevent clumping. You can't substitute them directly because powdered sugar absorbs more liquid and creates different textures. Use caster sugar for structure, powdered sugar for smooth icings.
How much regular sugar equals 1 cup caster sugar?
Exactly 1 cup. They have identical sweetness and density (about 200g per cup). The only difference is crystal size. Regular granulated sugar just takes longer to dissolve, so it may create slightly grittier textures in delicate recipes like custards or meringues.
Can I use brown sugar instead of caster sugar in meringues?
No. Brown sugar contains molasses and larger crystals that won't dissolve completely in egg whites. This creates a grainy texture and prevents proper foam formation. The molasses also adds weight and interferes with the protein structure. Stick to white caster, superfine, or processed granulated sugar only.
Does coconut sugar measure the same as caster sugar?
Yes, use a 1:1 ratio by volume. However, coconut sugar has larger crystals and slightly less sweetness (about 75% vs 99% sucrose). Increase creaming time by 2-3 minutes when mixing with butter. The finished product will have light caramel notes and slightly darker color.