Why do bakers put simple syrup on cakes?

Bakers put simple syrup on cakes for a few key reasons. The main purpose is to keep the cake moist. Simple syrup helps prevent the cake from drying out. It also adds sweetness and flavor to the cake. Using simple syrup can result in a cake that stays fresher for longer. Read on to learn more about why bakers use simple syrup and how it impacts cakes.

What is Simple Syrup?

Simple syrup is a mixture of equal parts sugar and water that is heated until the sugar dissolves. It results in a thick, sweet liquid. Simple syrup can be flavored in many ways by adding extracts, herbs, spices, citrus zest, vanilla, or other ingredients. Simple syrup is easy to make at home, requiring just two ingredients.

The basic simple syrup recipe is:

  • 1 cup sugar
  • 1 cup water

Heat the sugar and water together in a small saucepan over medium heat. Stir continuously until the sugar fully dissolves. Remove from heat and allow to cool. Store leftover simple syrup in the refrigerator for 2-3 weeks. Simple syrup can be reheated as needed before use.

Keeping Cakes Moist

The main reason bakers use simple syrup is to keep cakes moist and prevent them from drying out. Cakes inherently dry out over time due to a few factors:

  • Evaporation – Moisture escapes the cake through evaporation.
  • Starch Retrogradation – Starches begin to recrystallize as the cake cools, squeezing out moisture.
  • Gluten Formation – Gluten networks form during baking, then contract as the cake cools.

As cakes lose moisture, they become dry, crumbly, and stale tasting. Simple syrup helps counteract these effects by reintroducing moisture into the cake. The syrup permeates the cake, interacting with starch molecules and gluten strands to keep them from tightening up. This leaves the interior soft and moist.

Brushing simple syrup on baked cakes can revive dryness and extend the cake’s freshness. It is commonly used for this purpose with sponge cakes, pound cakes, white cakes, and other delicate crumbed cakes prone to drying out. The syrup is brushed on top of just-baked cakes while they are still warm so that it can properly soak in.

Adding Sweetness

In addition to moisture, simple syrup adds sweetness to cakes. Sugar itself has hydrophilic properties, meaning it attracts and retains moisture. So the sugar in simple syrup further improves moisture retention.

Simple syrup often contains more sugar than cake batters themselves. Cake recipes typically use around 1 cup sugar for 2-3 cups of flour. Simple syrup is a 1:1 ratio of sugar to water. So brushing syrup on a cake effectively increases the overall sugar content. This added sweetness enhances flavor.

The type of sugar used can also impact flavor. Simple syrup made with granulated white sugar has a clean sweetness. Brown sugar or coconut sugar will provide deeper caramel and molasses notes. The syrup can also be infused with vanilla, spices, citrus, or other flavorings to complement the cake.

Improving Texture

Simple syrup doesn’t just improve moisture – it also enhances the texture of cakes. Brushing syrup on crumb cakes can give the crumbs a chewy, sticky quality. It helps bind together the crumble topping so it doesn’t become too dry and flaky over time. The syrup also cascades down the sides of Bundt cakes and pound cakes, giving a sweet, lacquered glaze effect.

Syrup paired with a chocolate ganache or frosting helps seal in the ganache, preventing it from melting or sliding off the cake. The thin syrup layer improves adhesion of thicker frostings as well.

Soaking a sponge cake or genoise with flavored simple syrups provides an extra layer of taste. Each bite bursts with syrupy moisture laden with notes of citrus, vanilla, caramel or other flavors. The syrup prevents the open crumb structure from becoming too dry.

Preventing Fruit from Drying Out

Fruit-filled cakes and fruit cakes also benefit from a soak with simple syrup. Fruits like berries, stone fruits, and citrus dry out easily. They tend to lose moisture faster than the surrounding cake does. Simple syrup helps keep the fruit stays plump, moist, and juicy. This prevents it from shriveling up into dry pieces.

The syrup also coaxes out more vibrant fruit flavor. Fruits soaked in syrup take on a candied quality. Cooking the fruit into the simple syrup further intensifies the flavor. It allows bakers to highlight and enhance the natural flavors of the fruit.

Allowing Time for Glazes to Set

Using simple syrup buys more time for glazes to set properly on cakes. Brushing syrup on the cake first creates a tacky surface for the glaze to adhere to. It prevents the icing or glaze from sliding off if the cake hasn’t cooled fully or if the environment is humid.

It also allows moisture to fully absorb into the outer layers of the cake before applying a glaze. This helps prevent the glaze from melting. Simple syrup acts as a moisture barrier so the glaze remains intact.

Adding Decorative Elements

In addition to flavor and function, simple syrup can provide decorative appeal on cakes. Drizzling syrup over finished cakes creates streaks of shine and color. Syrups infused with fruit juices or colored with food gels naturally tint the glaze.

Syrup pools attractively around textured cake decorations like crushed nuts, chocolate shavings, or candied fruit. Syrups made with different sugars like coconut sugar or brown rice syrup produce uniquely hued drizzles.

Types of Simple Syrups for Cakes

Simple syrup can be flavored in any number of ways. Bakers can customize syrups to complement the cake flavors.

Basic Simple Syrup

The basic equal parts sugar and water simple syrup works for neutral cakes. Granulated white sugar makes a clear, thin syrup.

Vanilla Simple Syrup

Vanilla simple syrup is perfect for accentuating vanilla cakes. Add 1-2 tbsp vanilla extract or vanilla bean seeds to the hot syrup and let steep 30 minutes.

Brown Sugar Simple Syrup

For deeper flavor, use brown sugar or coconut sugar. Heat the syrup longer to dissolve the sugar fully. Adds nice caramel and molasses complexity.

Herb Simple Syrup

Herbal simple syrups infuse the sugar with herb flavors. Try rosemary, lavender, basil, mint, or thyme syrups on citrus or olive oil cakes.

Spice Simple Syrup

Warming spices like cinnamon, nutmeg, ginger, and cardamom can be infused into simple syrups. Use them on spice cakes or fruit cakes.

Citrus Simple Syrup

For bright flavor, simmer citrus peels in the syrup. Try lemon, lime, orange, or grapefruit. Strain out peels before using.

How to Use Simple Syrup on Cakes

Using simple syrup on cakes is easy. There are a few techniques for getting the right coverage and absorption into your cake:

Brush on Syrup

Use a pastry brush to lightly coat the top and sides of just-baked cakes with warmed syrup. Rotate the cake and brush until the top surface appears wet and glossy. For quicker absorption, poke holes in the cake first with a toothpick or skewer. This allows the syrup to soak into the interior.

Pour Syrup

Drizzle room temperature or warm syrup over the top of finished cakes and allow it to cascade evenly over the sides. Use a spatula to coat any bare areas. Let the syrup soak in for 5-10 minutes before topping with frosting or decorations.

Syrup Soak

For maximum moisture, poke holes across the top and sides of the cooled cake using a skewer. Sprinkle a few tablespoons of syrup over top, allowing it to pool in the holes. Repeat until the surface appears saturated. Let rest 10 minutes to fully absorb before frosting or serving.

Syrup Glaze

For fruit cakes or sticky buns, cook down the syrup until thickened to a glaze consistency. Brush the glaze over cake layers or coat the entire cake for a shiny finish.

Sugar Syrup

Make a flavored sugar syrup by cooking fruit, herbs, or spices directly into the simmering simple syrup. Cool completely before using. Paint onto cakes or use to soak layers.

Simple Syrup Cake Recipes

Here are some delicious cake recipes that benefit from being brushed or soaked with simple syrup:

Lemon Simple Syrup Pound Cake

Lemon simple syrup drizzled over a classic vanilla pound cake. The citrus syrup soaks in keeping each slice moist.

Brown Sugar Cinnamon Cake

Homey brown sugar cinnamon cake soaked with a cinnamon simple syrup. The syrup adds spice and richness.

Blackberry Simple Syrup Sponge Cake

Fluffy vanilla sponge cake layered with blackberry simple syrup for fruity moisture in each bite.

Rosemary Olive Oil Cake with Lemon Syrup

Subtle rosemary olive oil cake topped with tangy lemon simple syrup for a nice contrast of flavors.

Ginger Peach Upside Down Cake

Caramelized ginger peach topping baked into an upside down cake soaked with brown sugar simple syrup.

Frequently Asked Questions

What is the ratio for simple syrup?

Simple syrup is made with equal parts sugar and water – typically 1 cup of each. The amounts can be scaled up as needed.

How long does simple syrup last?

Refrigerated simple syrup will keep for 2-3 weeks. For longer storage, freeze simple syrup for up to 3 months.

Should simple syrup be warm or room temperature when brushing on cake?

Warm or room temperature syrup works best for absorbing into cakes. Cold syrup will take longer to soak in.

Can I flavor simple syrup?

Yes, simple syrup can be infused with vanilla, herbs, spices, extracts, citrus, fruit juices, and more to create flavored syrups.

What types of cakes work well with simple syrup?

Simple syrup works nicely on pound cakes, sponge cakes, cinnamon cakes, upside down cakes, Bundt cakes, fruit cakes, and layer cakes.

How much simple syrup should be used on a cake?

A few tablespoons is usually adequate for a single layer cake. Brush on just enough to make the top glisten without pooling. Adjust amounts as needed for larger cakes.


Simple syrup is an easy secret ingredient used by bakers to keep cakes fresh and moist. The sweet liquid permeates the cake crumb, combating dryness. It also coaxes out more vibrant fruit flavors and provides a shiny, lacquered finish. Simple syrup can be infused with many flavors to customize to any cake recipe. Keeping a batch on hand allows home bakers to revive stale cakes and keep their baked goods tasting great.

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