Why do you add simple syrup to cake?

There are a few key reasons why bakers add simple syrup to cakes:

  • It helps keep the cake moist – Simple syrup helps prevent baked goods like cakes, cupcakes and muffins from drying out too quickly. The sugar in the syrup binds to the starches in the flour, helping lock in moisture.
  • It adds flavor – Simple syrup can be infused with different flavors, extracts and herbs to enhance the flavor of cakes and other baked goods. Vanilla, almond, lemon, rosewater and lavender are popular flavorings.
  • It acts as a glaze – Brushing simple syrup over cakes creates a shiny, glossy glaze on the top. This helps seal in moisture and gives the cake an attractive sheen.
  • It sweetens without adding volume – Simple syrup dissolves sugars in water, giving a very concentrated sweetness without adding volume like granulated sugar would. This allows sweetening baked goods without compromising the texture.

So in summary, simple syrup gives cakes extra moisture, flavor and sweetness without negatively impacting the crumb and texture. Professional bakers rely on simple syrup to improve the quality, taste and appearance of cakes.

What is Simple Syrup?

Simple syrup is a mixture of equal parts granulated sugar and water, boiled until the sugar fully dissolves. Once cooled, it results in a clear, thick, sugary syrup.

The basic ratio for simple syrup is:

  • 1 cup sugar
  • 1 cup water

However, this can be adjusted to make a richer or thinner syrup depending on the application. More sugar dissolved into the water makes a thicker, sweeter syrup.

Simple syrup can be flavored in many ways:

  • Vanilla – Add vanilla beans or extract
  • Spices – Cinnamon sticks, cloves, cardamom pods
  • Citrus – Lemon, lime, orange zest
  • Herbs – Rosemary, thyme, mint
  • Flowers – Rose, orange blossom, lavender
  • Other extracts – Almond, coconut, peppermint

The key is to add flavorings when the syrup is hot to allow them to infuse, then strain out solids. Flavored syrups provide an easy way to add new dimensions to all kinds of baked goods.

Why Use Simple Syrup Instead of Granulated Sugar?

There are a few advantages of using simple syrup rather than regular granulated sugar:

  • Fast dissolving – Sugar dissolves almost instantly into simple syrup, whereas it takes time for granulated sugar to dissolve into batters and frostings.
  • Smoother texture – Dissolved sugar in simple syrup won’t create graininess or clumps like granulated sugar can.
  • Won’t deflate batters – Stirring in granulated sugar can knock air out of cake batters and meringues. Simple syrup incorporates smoothly without deflating.
  • Won’t crystallize – Sugar crystallization happens when there’s too much undissolved sugar in a mixture. Simple syrup avoids this issue.

So in many baking applications, simple syrup results in a more reliable end product with better moisture and texture. The dissolved sugar is able to penetrate the entire cake or cupcake more evenly.

How to Make Simple Syrup for Cakes

Here is an easy recipe and method for making basic simple syrup at home to use for cakes, cupcakes, cookies and other baked goods:


  • 1 cup granulated white sugar
  • 1 cup water
  • Pinch of salt (optional)
  • Flavorings of your choice (optional)


  1. Combine the sugar, water and salt (if using) in a small saucepan. Heat over medium-high heat, stirring frequently, until the sugar fully dissolves.
  2. Once dissolved, bring the mixture to a simmer and cook for about 2-3 minutes. Remove from heat and allow to cool slightly.
  3. Add any flavorings, extracts or herbs. Vanilla and almond extracts are common options. Let stand for at least 15 minutes to allow flavors to infuse.
  4. Strain the syrup through a fine mesh sieve to remove any solids or debris. Cool to room temperature before using.
  5. Store cooled simple syrup in an airtight container in the refrigerator for up to 2 weeks.

The resulting simple syrup can be substituted 1:1 for granulated sugar in recipes for cakes, cupcakes, muffins and other baked goods. Always account for the added liquid in the syrup when balancing out your recipe.

For richer, thicker simple syrup increase the sugar to 2 cups. For thinner syrup, use more water than sugar. Adjust to your preference.

Tips for Using Simple Syrup:

  • When brushing syrup onto baked goods, it’s best when warm. Reheat before using for optimal penetration.
  • Don’t over-saturate or soak cakes with too much syrup. It can make the texture soggy.
  • For maximum shelf life, brush syrup on cakes and cupcakes once they have cooled completely.
  • Store cakes brushed with syrup at room temperature, not refrigerated or they can become sticky.
  • Make flavored syrups to match the flavors in a cake recipe, like vanilla, almond, coconut, etc.

With the right technique, simple syrup elevates the flavor, moisture and presentation of cakes for a bakery-quality product.

How Simple Syrup Keeps Cakes Moist

The sugar in simple syrup acts as a natural humectant in cakes and quick breads. This means it helps retain and preserve moisture in baked goods. Here’s how it works to keep cakes deliciously moist and soft:

Sugar Absorbs Moisture

Granulated sugar contains very little moisture – usually less than 1% water content. When sugar absorbs water, it physically binds the water molecules to itself.

When sugar is boiled into a syrup, it becomes fully saturated with water and can’t absorb any more. This allows it to release and deposit the moisture into low-moisture baked goods like cakes, muffins and cookies.

Sugar Competes with Starches

Starches in flour, like amylose and amylopectin, are also good at soaking up available moisture. This can result in dried out baked goods.

When simple syrup is added, the sugar competes with starches to bond with the available water. The saturated sugar in the syrup wins, blocking the starches from absorbing as much moisture.

Sugar Lowers Cooking Temperature

Sugar also helps retain moisture by lowering the gelatinization temperature of starches. This allows starches to gelatinize at lower oven temperatures during baking. More gentle heating means less moisture is evaporated from cakes.

Sugar is Hygroscopic

In finished baked goods, sugar attracts moisture from the air through a process called hygroscopy. The added humidity absorbed by the sugar then transfers into the cake to keep it moist.

So in multiple ways, the sugar in simple syrup helps lock in, retain and introduce new moisture into cakes. This moisture-preserving power is the main reason syrup leads to tender, juicy cakes with superior lasting quality.

How Much Simple Syrup to Use in Cakes

The amount of simple syrup added to cakes depends on a few factors:

  • Cake size and shape
  • Desired sweetness level
  • Number of cake layers
  • Cake flavors
  • Icing or frosting

For a typical 8-inch round 2-layer cake, here are general syrup guidelines:

Brushing Syrup:

  • 2-4 Tablespoons for subtle moisture
  • 1/4 to 1/3 cup for thorough saturation

The more syrup brushed, the sweeter and moister the final cake will be.Brush each layer separately before stacking and frosting.

Syrup Baked Inside:

  • 2-3 Tablespoons substituted for sugar in the cake batter itself

When baking syrup directly into cake batter, take care not to make the batter too thin or compromise rising.

Syrup Soaking:

  • 1/4 to 1/3 cup soaked gently into cake after baking

Poke holes and drizzle syrup over hot baked cake layers before assembly and icing. Allows maximum absorption.

For richer, sweeter cakes you can use up to 1/2 cup syrup total for more intense saturation. Scale the amount based on cake size and personal preferences.

Too much can make cakes gummy and syrupy. Start with less syrup and increase as needed to lock in moisture while maintaining a tender, cake-like crumb.

What Can You Use Instead of Simple Syrup?

While simple syrup is ideal for flavor and moisture balance in cakes, there are some substitutions you can use in a pinch:

Granulated Sugar

Replace 1 cup simple syrup with 1 cup granulated white sugar. Use half the amount when mixing into batter to avoid thinning it out too much. May need to bake slightly longer. Won’t provide as much guaranteed moisture.

Corn Syrup

Substitute 1:1 for simple syrup. Provides similar moisture benefits without altering flavor.


Replace up to 1/2 the simple syrup with an equal amount of mildly flavored honey. Adjust any other liquids to compensate. Provides moisture with some flavor change.

Maple Syrup

Swap 1:1 for simple syrup. Imparts distinct maple flavor.

Fruit Juice

Substitute an equal amount of juice, like orange, apple, or pineapple juice for some simple syrup moisture and flavor.


Boost cake flavor by replacing up to half the simple syrup with extracts like vanilla, almond, coconut or lemon. Adjust liquid amounts.

While not exact substitutes, these alternatives can provide workable options for moisture, sweetness and flavor in a cake recipe if you don’t have simple syrup on hand.

Frequently Asked Questions

Should you brush simple syrup on cake before or after frosting?

It’s best to brush simple syrup on baked cake layers while they are still warm from the oven, before assembly and frosting. This allows the syrup to fully penetrate and soak into the cake for maximum moisture.

Is simple syrup necessary for cake?

Simple syrup is not absolutely necessary, but it does improve moistness, flavor and sweetness in many types of cakes. It helps prevent drying out and gives a finer, smoother crumb. It provides the most benefit in lighter cakes like sponge and chiffon.

How long does simple syrup last?

Stored in an airtight container in the fridge, simple syrup will keep for 2-3 weeks. For maximum freshness, use within 1-2 weeks. Sugar eventually crystallizes with longer storage.

Can you flavor simple syrup?

Yes, simple syrup can be infused with many flavors by adding extracts, herbs, citrus zest or other aromatics when hot. Vanilla, almond, rosewater and lavender syrups are especially common. Let cool completely before using.

What’s the difference between simple syrup and sugar water?

Simple syrup contains equal parts sugar and water for a balanced sweetness and moisture level. Sugar water is just sugar dissolved in water at varying dilution. The syrup consistency ensures the sugar won’t recrystallize as readily.


Adding simple syrup to cake batter, brushing it on layers or soaking baked cakes provides a simple way to lock in moisture, enhance flavor and sweetness, and improve the overall quality of cakes. The dissolved sugar binds with water, prevents staling, and gives cakes a fine, tender texture. While not absolutely essential, bakers rely on this basic syrup to take their cakes to the next level. Experiment with amounts and flavors to find your perfect simple syrup for creating deliciously moist cakes.

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