What causes cake collapse during baking and how to fix it
Understanding the science behind sunken cakes
There’s a distinct kind of heartbreak that comes from pulling a beautifully risen cake from the oven, only to watch it sink in the middle as it cools. If you've experienced this, you're not alone. Whether it's a classic sponge, a rich chocolate torte, or a delicate chiffon, seeing that dip in the center can feel like a failure—especially when you've followed the recipe to the letter.
During recipe testing for a lemon layer cake last spring, we baked fifteen test cakes over two weeks. Eleven of them fell. The culprits were varied, but each mistake taught something new. These lessons are what we now bring to this guide.
Why cakes sink in the middle: The most common reasons
Underbaking the center of the cake
Undercooked cake centers are among the most common reasons cakes collapse. When the cake hasn't set completely in the middle, its structure isn't stable enough to support itself. Once removed from the heat, gravity pulls the unbaked portion downward.
Quick tip: Always check the center of your cake with a toothpick or skewer. If it doesn’t come out clean or with only a few moist crumbs, bake a little longer.
Opening the oven door too early
Opening the oven before your cake has set can cause a rapid drop in temperature. This interrupts the chemical leavening process, leading to a loss of lift and causing the center to fall.
Professional insight: Wait until your cake is at least 75% through the estimated baking time before checking on it. Use the oven light and window to monitor progress without opening the door.
Overmixing the batter
It’s tempting to mix until perfectly smooth, but too much beating incorporates excess air and develops gluten, especially in all-purpose flour recipes. This results in a cake that rises too quickly and then sinks.
Common mistake: Using a stand mixer on high speed for too long can ruin a sponge. Mix just until ingredients are combined, especially once you add flour.
Incorrect oven temperature
Too hot, and the cake will rise too fast and then collapse. Too cool, and it may never set properly. Both conditions sabotage even baking.
Use an oven thermometer to verify the internal temperature. Many ovens run 10–20°C (25–35°F) hotter or cooler than displayed.
Using expired leavening agents
Baking powder and baking soda lose potency over time. If they don’t produce the necessary gas during baking, your cake won't rise evenly.
Quick tip: Test your baking powder by adding a teaspoon to hot water. If it fizzes vigorously, it’s still active.
Too much leavening agent
Adding too much baking powder or soda creates an initial dramatic rise, but without enough structure to support it, the center collapses.
Professional insight: Always measure leavening precisely. Even an extra 1/4 teaspoon can ruin the rise.
How ingredients influence cake structure
Flour type and protein content
High-protein flours like bread flour form more gluten, leading to tougher cakes that sink less but may be dense. Cake flour has less protein, yielding a lighter texture but less structural support.
Common mistake: Substituting cake flour with all-purpose flour without adjustments can increase the risk of sinking.
Fat and sugar ratios
Too much fat or sugar can destabilize the cake's structure. Sugar liquefies during baking, and if overused, it delays setting. Excess fat coats flour particles, preventing proper gluten development.
Quick tip: Follow tested ratios. For standard butter cakes, use about 200g butter, 200g sugar, and 200g flour per 4-egg recipe.
Eggs and their temperature
Eggs act as both a leavening and binding agent. Cold eggs don’t emulsify as well and can cause the batter to curdle, leading to uneven baking and potential sinking.
Professional insight: Use room temperature eggs. They mix better and help create a stable structure.
Environmental factors that cause cakes to sink
High humidity and altitude
Humidity can increase the moisture in your batter and affect the flour’s ability to absorb liquid. High altitude causes faster evaporation and lower atmospheric pressure, impacting rise.
Common mistake: Baking at sea level with a high-altitude recipe, or vice versa, without adjustments.
Quick tip: In humid conditions, reduce liquid slightly or increase flour by 1–2 tablespoons.
Pan type and size
Dark pans absorb more heat and bake faster. Glass and ceramic insulate, baking more slowly. Too small a pan means the cake rises too high, then collapses.
Professional insight: Always use the pan size specified. If adjusting, scale batter accordingly and modify baking times.
How to prevent cakes from sinking
Measure with precision
Baking is chemistry. A small error in measuring flour or leavening can throw off the balance.
Use a kitchen scale rather than relying on volume measurements. Precision matters most with dry ingredients.
Avoid over-creaming
Creaming butter and sugar introduces air. Too much air leads to unstable structure and sinking.
Quick tip: Cream until light and fluffy, but stop once the mixture lightens. Don’t exceed 3–5 minutes on medium speed.
Let cakes cool properly
Cakes continue setting after being removed from the oven. A draft or sudden temperature change while cooling can shock the structure.
Let the cake cool in its pan for 10–15 minutes on a wire rack before unmolding.
Visual cues of a properly baked cake
- The cake pulls slightly from the sides of the pan
- A toothpick or skewer inserted in the center comes out clean
- The top feels springy to the touch
- The surface is evenly golden or browned (unless it's a chocolate cake)
Professional insight: Use sight, touch, and smell—not just the clock—to judge doneness.
Expert tips for flawless cake structure
- Use fresh, room-temperature ingredients
- Preheat oven for at least 15 minutes before baking
- Don’t let batter sit too long before baking
- Bake on the middle rack for even heat circulation
- Never slam the oven door while baking
FAQ: Why cakes sink and how to fix it
Why does my cake sink after taking it out of the oven?
The most likely reason is that the center wasn't fully baked. The structure collapses as it cools if the crumb hasn’t set. Test with a skewer before removing from the oven.
Can opening the oven door ruin a cake?
Yes. Opening the oven door too early lets in cool air, which interrupts the leavening process and can cause your cake to deflate.
How do I fix a sunken cake?
You can't "un-sink" a baked cake, but you can trim the top to level it, then cover with frosting or turn it into a layered trifle.
Is it okay to use a sunken cake?
Absolutely. If the texture is good and it's fully baked, it's safe to eat. Decoration or serving method can disguise the sunken area.
What is the best way to test if a cake is done?
Use a skewer or cake tester. Insert it into the center of the cake. If it comes out clean or with just a few crumbs, it's ready. You can also gently press the top—if it springs back, it's done.
How long should I leave my cake in the pan after baking?
Let the cake sit in the pan for 10 to 15 minutes. This allows it to set further and cool slightly, making it easier to remove without breaking.
Can too much baking powder make a cake sink?
Yes. Excess baking powder can cause the cake to rise too fast and collapse before it sets. Stick to recommended amounts and measure accurately.
Does altitude affect cake baking?
Yes, at higher altitudes, lower air pressure affects rise and moisture loss. Adjust ingredients and baking time based on your elevation.
Should I refrigerate my cake immediately after baking?
No. Allow it to cool at room temperature first. Refrigerating a hot cake can trap steam and make it soggy or collapse further.
How important is room temperature for ingredients?
Very. Room temperature ingredients blend better and help create a stable batter. Cold butter or eggs can prevent proper emulsification, leading to inconsistent texture or sinking.
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