Cake falls down after getting out of the oven

Question

The cakes I bake at home consistently fall after getting them out of the oven. The issue is always the same: while baking in the oven the cake does rise (sometimes more than others, but it rises), but after opening the oven and taking it out it deflates slowly, but completely (absolutely no bubbles inside).

The only thing that has worked so far was modifying a recipe to add copious amounts of sunflower oil (like 400 ml - although I have not experimented with less) - the cake did retain some of the rise after. But pretty much all recipes I see do not even use oil.

Currently I trying to rule down causes, so I am repeating the same recipe in multiple ways to try to nail down the problem.

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What I have tried so far:

• Using well tried recipes from trusted sources. I want to make said recipe has already worked for multiple people
• Make sure the oven is pre-heated (180°C, no forced ventilation)
• Measure the oven temperature with a thermometer (it matches the dials very well at the centre of the oven)
• Only the cake goes into the oven (in the middle of the oven), nothing else
• Use fine cake flour pre-mixed with baking powder (bought already mixed), or
• Use regular flour (i.e. not fine flour specific for cakes) and pre-mix myself with baking powder in a separate bowl before using it in the recipe. Here I have also tried to use more baking powder than recommended
• Sift the flour
• Use a ceramic container instead of metallic (supposedly it takes longer to get hot, allowing the batter at the edges to rise better)
• Use a whisker to mix the batter (instead of a spoon). I do mix the batter energetically (no flour lumps remain), but I suppose not as much as would be possible with an electric mixer
• Mix the stiff egg whites (I turn the egg whites upside down to make sure they are done) by hand with a spatula (to avoid loosing the air). I just found this one out about a week ago, so I have not yet tried it with the fine cake flour.
• Use the toothpick test to check if the cake is done before removing it.
• Let the cake sit in the oven and gradually decrease its temperature - 5 min after turning off, open the door a few mm and leave it another 10 mins like that. This I tried only once, and since the recipe was the same, I already knew the cooking time and did not need to open the oven beforehand to check if it was done.

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Things I am unsure of/would like to explore:

• Batter consistency/stiffness: because I mix by hand, it gets hard to whisk everything together if the consistency is hard. My attempts usually end up with rather soft (i.e. easy to whisk) consistency. I am unsure if this is significant, or how important is the consistency of the batter for the end result
• (Related to the above): does my recipe have enough flour (read somewhere that this might be a cause for the cake falling).
• Is the cake really done (read somewhere that might also be a cause)? My cakes usually bake 40 - 50 min (depending on toothpick results). That sounds enough, but I have not experimented with letting them bake further. I am not sure at what point would they overbake.

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The recipe I am currently experimenting with:

• 125 g potato starch + baking powder
• 7 eggs
• 150 g sugar

Separate yolks from whites; Join suggar with yolks, then mix flour in; beat the whites stiff and add them carefully; bake everything 30 - 40 min.

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Recipe with wheat flour tried some years ago:

• 5 eggs
• 200g sugar
• 200g cooking chocolate
• 100g butter (used margerine)
• 200 ml milk
• 200g flour + teaspoon baking powder

separate yolks from whites; melt chocolate + butter in water bath; join yolks with melted butter + chocolate; add in milk and flower in small amounts while mixing; Beat whites stiff and add carefully to the batter ( I likely didn't add carefully back then); Bake at 180°C for 50 - 60 min (do not remember exact time - likely around 50 min, passed my toothpick test).

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What could I be doing wrong/could I try to find and fix this?

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Update: after trying again the chocolate cake recipe (with a bit more butter and less milk), I managed to successfully bake a cake! The result was way above my expectations.

I think the issues until now were:

• For the first recipe with potato starch, I likely do not have access to the same ingredient as my mother (we live far away), which causes the different outcome. I am also not sure about rise, but I know her cake was fluffy;
• For the second recipe, likely I used too little fat (and possibly sugar). I guess I was trying not to make a cake too unhealthy and not following the recipe to the letter. I definitely was screwing up the egg whites.

I now have a proven baseline recipe some theoretical knowledge I can use to further experiment with. Thanks a lot!

Answer 1

Rising in the oven has nothing to do with the final shape/height of the cake. Pretty much every cake is higher in the oven than afterwards. So, stop watching for rise in the oven when trying to troubleshoot. Also, as commenters said, don't declare the cake problematic just because it deflates when cooling - the way to recognize a wrongly-deflated cake is when, after cooling, the texture isn't properly spongy, no matter how high or low the cake happens to be.

The recipe you're currently making is practically predestined for falling - it's not really a cake recipe. You're using starch, which has no gluten. This makes it impossible for the cake to retain the aeration. Also, it's chock-full of eggs. What you're making is closer to a souffle than a cake, and it falls like a souffle.

I can't say why your second recipe didn't work - it looks quite reasonable, except for the high amount of milk. It does have somewhat complex steps, so maybe you made a mistake in one of them, or maybe even it wasn't that bad a cake, but now that your new non-cake is falling dramatically, you're thinking "hey, back then, it also didn't look as great as when inside the oven".

I'd recommend that you start by using a normal cake recipe. It should have wheat flour, eggs, sugar and fat, possibly some liquid in the form of dairy or a fruit puree. As long as you're having problems rising, it's better to also use a recipe that includes baking powder, as opposed to recipes that rely on egg-foam only, or recipes that combine baking soda with hopefully-the-exact-amount-of-acid-from-other-ingredients.

I don't have my usual baking books close by to give you ratios, but try using recipes that are close to 1:1 by weight for all ingredients, maybe up to 50% difference - so something between 2 and 5 eggs for 150 g flour, not 7 eggs per 150 g flour. Also, don't go for anything exotic like whole-wheat flour, alternative sweeteners, etc., these have a higher chance of not working. If you want to have any add-ins (nuts, chocolate chips, pieces of dried fruit, or similar) try to not exceed 50% of the flour weight, and only choose add-ins which are small in size and don't add much water. For example, some raisins will be OK, but not raw fruit.

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To your three specific subquestions:

• The batter consistency doesn't matter. One of my favorite cake recipes has such stiff batter, it stays in lumps when I put it into the pan. There are also very nice cakes which happen to have a liquid batter. Just stick to your recipe and don't worry about batter thickness, it's purely accidental to the recipe.
• as for flour: there are good cakes with little flour, but when troubleshooting, try staying close to classic ratios. And really use flour - starch is not flour. Flourless cakes exist, but they're more difficult to get right, and not all of them are supposed to rise.
• Is the cake really done: yes, the toothpick test is reliable on a normal cake, and 40-50 min is on the long side for a flat cake. A bundt cake may be done in that time, or need a bit longer. You can't recognize an overbaked cake in the oven, as long as you don't char it; it's only noticeable after it has cooled and the texture is all wrong, harder and dryer than the same recipe baked for the proper time.