This is why your cake collapses (part 1)

This is why your cake sinks

Hands down, this is the question I hear the most.

Truth be told, there is no one-answer-fits-all.

It could be a thousand different things. A sunken sponge can be caused by any number of things - some well-known, others a little more unexpected. We’ll walk through a few of them here.

As a baker, whether you’re whipping up cakes in a home kitchen or running a pastry line, it’s essential to understand the specific pitfalls of different cake types.

A Pound cake collapses for entirely different reasons than an Angel cake. Forget to cool a Chiffon cake upside down? It’ll sink like a soufflé. A butter cake? Totally different story… you see where this is going.

Right… aprons on - let’s dive in.

Underbaking

It might sound cliché, but it’s still the top culprit. Underbaking is often the number one reason your cake sinks like a ship in the Bermuda Triangle. So don't just thrust your eyes - check for doneness with the good ol’ wooden skewer.

→ Insert it into the center of the cake at a diagonal (you’ll get a more accurate read). If it comes out clean, your cake is ready.

Too much leavening

It’s an easy mistake - especially when a recipe calls for baking soda or baking powder. However baking is a pure science, and even the tiniest tweak can throw everything off.

You’re creating airy, unstable bubbles without the structure to support them. Cue the collapse.
Sooooo… measure, measure, MEASURE.

→ Don’t: measuring spoons. Do: A quality scale and go by grams.
→ Remember: Rapid rise often means a quick collapse.

Overbeating your foam (egg foam based cakes)

This one’s similar to the ‘Too much leavening’ issue above. Sponge cakes rely on air for their lift (coming from beating it into your egg foam). Think Genoise, Chiffon and Angel cakes mainly.

But if you overwhip? You’re building a tower on shaky bubbles. The cake rises too quickly, then collapses under their weight.

→ Tip: Whip eggs until they form ribbons, not peaks. You want them thick and pale, not dry or too foamy.

Underbeating your foam (egg foam based cakes)

Surprise surprise - too little air can be just as problematic. If your egg foam doesn’t reach full volume, it won’t have the strength to support the flour and fat you fold in later. Resulting in a heavy batter, lacking lift.

But there is more —> Underbeating means fewer air bubbles and weaker structure to trap the steam and support rising. The cake may rise slightly, but will then collapse as it cools.

→ Underbeating = less air, less structure, less rise → more collapse.

Tip: Take your time. Beat the eggs until they’re thick, pale and full of volume. Don’t stop short.

STOP OPENING YOUR OVEN

Tempting? Yes. Detrimental? Absolutely. Resist the urge to have a peek and do NOT open your oven for the first 20 (better, 30) minutes of baking.

Cracking the door drops oven temp instantly, messing with the bake and weakening your cake’s structure mid-rise.

I mean, you'll have to open the oven eventually, why sabotage it now?

‘It’s too hot in here’

Yes, your oven could be too hot. This means a fast rise and that usually equals a weak structure - we’ve been here before. Why? The outside of your cake sets too quickly before the interior has had a chance to rise and stabilize.

At the same time, the middle balloons up (hello, dome effect) as air and steam expand rapidly. The interior? Still underbaked. The structure hasn’t formed properly, and as the cake cools, the soft center caves in - dragging all the work down.

Avoid the drama:
→ Check your oven temperature regularly. Get it calibrated. All ovens are different; keep that in mind
→ Skip a convection (fan-based) oven - unless the recipe calls for it. The fan-based ovens tend to overbake the outside. This is especially true for delicate cakes like Chiffon and Angel cakes. More about those in a minute.
→ Stick to the temperatures mentioned in the recipes. Seriously. Don’t be a smartass.

Beating too slow or too fast - especially true for a Genoise

Aim for medium and controlled speed. That’s the sweet spot. Bubbles stay uniform, fine and stable - which is critical for holding structure. A medium speed gives proteins the time to partially denature and strenghten the foam.

Going too slow = weak structure. Leads to either a dense cake or one that collapses
Going too fast = large unstable bubbles will deflate rapidly when you fold in the flour or during baking.

Why is this extra important for a Genoise?
→ Genoise doesn’t rely on chemical leaveners and the rise depend solely on the egg foam.
→ It’s made with whole eggs, not just whites. That yolky fat? It weakens the bubbles, making stability even trickier.

Greasing the pan (cakes that purely really on egg foam)

Wait-shouldn’t you always grease the pan? Normally, yes—if you plan to get the cake out in one piece and actually eat it.

But for some cakes, greasing the pan is one of the worst things you can do. Okay, maybe not the worst… but definitely not helpful. Here’s why:

When a cake rises - especially one that relies purely on egg foam - it needs something to grip. Greasing the pan creates a slippery slope (literally), which stops the batter from climbing the sides.

Result?
- A batter that slides down
- Cake that can’t hold its rise
- Sunken, dense or collapsed cake.

Skip greasing the pan when baking:
→ Angel food cakes – 100% egg white foam, no fat, no leavening. They rely on sugar to stabilize the foam, and absolutely need to cling to the pan to rise.

→ Chiffon cakes – Made with oil and egg whites (hence the nickname mayonnaise cake). It has fat, but still needs that grip to rise properly.

→ Important: Both Angel and Chiffon cakes should be cooled upside down right after baking. They’re delicate and tend to contract more than other cakes while cooling. Inverting helps them keep their volume and prevents a sunken middle.

That’s also why you’ll often see these cakes baked in tube pans - they’re perfect for flipping. Gravity keeps the structure stretched while the cake sets and the internal pressure evens out. Science meets sponge.

Other cake-sinking culprits you might not know (yet)

Before we wrap things up, here are couple of lesser-known troublemakers worth mentioning:

Dutch-processed Cocoa Powder

If you’re baking a chocolate cake (and I hope you are), keep an eye on the cocoa you’re using. Dutch-processed cocoa powder is treated with an alkali to neutralize its acidity. That sounds fancy - but it can interfere with protein setting, leaving your cake open and vulnerable to collapse.

Bleached vs. Unbleached flour

Flour choice matters more than you think. Bleached flour helps set the cake structure faster, which can reduce the risk of sinking - especially in extra-sensitive cakes. Unbleached flours? A little slower to set, and that might cause issues in delicate bakes. But honestly, that topic deserves its own deep dive.

That’s a wrap on Part 1. Hopefully, you picked up a few tips (or at least a couple of aha! moments).

More cake truths are on the way - so stay tuned, keep whisking smart, and let me know what surprised you the most.

PS. A quick tip on baking soda:
Want to tame that overzealous rise? Pour boiling water over your dry ingredients (yep, including the baking soda), give it a stir, and let it sit for 10 minutes.

This helps release some of the initial carbon dioxide, dialing down the leavening power and reducing the risk of your cake collapsing later on. Smart move, especially in recipes that tend to puff and sink. Give it a try.