Why is there a big bulge in the middle of the cake roll when baking?

As we all know, cake rolls are a common type of cake dessert. They are made in a variety of ways, with rich flavors, sweet and delicious taste, and soft texture. Many people like to eat them. Some people find that the middle of the cake roll is bulging when making it, so what is the reason for the bulging in the middle of the cake roll? Let's take a closer look!

Reasons and solutions for bulging in the middle of baked cake rolls

1. Over-whipping the egg whites

Whipping egg whites is a very critical and most error-prone step in making chiffon cakes or cake rolls. To what extent should egg whites be whipped?

The whipping degree of chiffon cake and cake roll is different. Chiffon cake is often required to be whipped to neutral to dry foam (any state in the middle is fine), that is, when the whisk is lifted, the egg whites can be in the shape of large curved hooks, small curved hooks, long uprights, or short uprights. Only then can the chiffon cake have better fluffiness, rise higher, and have a more delicate, soft and fluffy texture.

But for the cake roll, because it needs to be rolled up, and the cake roll is not as thick as the chiffon cake, the cake roll only needs to be whipped to a neutral and slightly moist state. That is, when the egg beater is lifted, the egg whites are drooping on the egg beater.

The cake roll made in this way tastes moist and is not easy to crack. After pouring the batter into the baking pan, shake the baking pan a few times and it will basically flow smoothly. If the batter is over-beaten, the cake roll will easily bulge because the puffiness is too strong, and it will become difficult to roll it up afterwards: it is easy to crack.

2. The egg yolk paste and egg whites are not mixed evenly

You can try to break open the baked cake slices and look inside to see if the bulge is a different color from the rest of the cake? The egg whites that were not mixed well will still be white after baking. If so, this is the reason.

There are two possibilities for not mixing well:

The first is that if the egg whites are over-beaten, it is easy to cause the mixture to be difficult to mix evenly. You may not be able to see it with your naked eyes, but there are many small pieces of egg white in the batter in an uneven state. It is possible that there is a large piece of egg white in the middle, so this piece expands greatly, which is different from the other batters and naturally bulges.

The second type is that people are afraid of losing bubbles and dare not stir more. In fact, if you pay attention to the technique and make sure that all the making utensils are clean, free of water and oil, the meringue is not as "fragile" as you think. Let's take a look at the mixing technique:

That is: the scraper moves from the 12 o'clock position of the basin to the 6 o'clock position, and when it reaches the bottom, scoop up the batter at the bottom, and then let it fall naturally. At the same time, use your other hand to turn the basin 180 degrees (try it in practice, and you will become proficient after practicing a few times.)

Finally, the correctly mixed chiffon batter should be thick and uniform, and can fall like a ribbon.

Unmixed flour lumps usually do not protrude on the surface, but hide in the cake body. When you break it open, it is a hard powdery lump. In your third picture, there are many bubble-like protrusions on the surface, so I think most of them are probably because the meringue is not mixed evenly with the egg yolk paste.

3. There is a problem with the oven temperature

You can turn the cake roll over and look at the back, which is the towel side. Is it a uniform color? Or is the bulge in the middle lighter than other places? If it is serious, even the middle part will be a little concave.

This result is caused by the same reason as the concave bottom of a chiffon cake, which is often accompanied by the top of the cake rising very high and cracking very badly. It is very similar to the bulging of a cake roll.

So what is the reason?

Some friends would say that it is caused by the high temperature of the bottom fire. You can say that, but it is not entirely true. The reason is actually because during the expansion process, the overall expansion speed is greater than the condensation speed of the cake batter at the bottom. The bottom has not yet been formed, but it is "pulled" up, and naturally concave upwards.

So how to solve it? If the overall temperature is appropriate, then you need to increase the bottom heat to make the bottom condense and stick faster so that it won't be pulled up. Of course, if the overall temperature is already too high, then you can only lower it.

Another possibility is that your oven temperature is uneven. However, most household ovens are more or less uneven. As long as the temperature difference is not too large, it will not cause bulging. So you have to first check whether you have baked other types of snacks: some places are already baked and colored, while other places are not even cooked?

4. About the amount of your batter

I think it's a bit too much. Chiffon cakes, no matter what kind of mold, should be filled to 70% at most, because they have a very strong expansion force. Excess batter often breaks out of the mold and takes on strange shapes. You must have seen some cakes with mushroom tops: this is mostly caused by too much batter.

Cake roll making skills

The first thing to use is low-gluten flour, which should be sifted and set aside. This step is to sift the flour as finely as possible to avoid the appearance of granular flour, which has a direct factor in the fineness of the cake baked later.

The second step is to control the degree of whipping of egg whites. Add sugar three times and beat the egg whites into long curved hooks. Then pour one-third of the egg whites into the egg yolks and stir slightly. Then pour the stirred egg whites into the remaining egg whites and stir. The stirring process must be even, but not over-stirring to avoid the formation of defoaming.

The appearance of bubbles in the middle of the cake roll may be due to the egg whites and egg yolks not being fully mixed during the stirring process.

The third step is to pour the mixed mixture into the mold, smooth it with a scraper, then lift the mold plate appropriately and shake it on the table to expel the gas in the mixture. This will reduce the hollowness inside the baked cake.

How to make cake roll

Prepare ingredients: 3 eggs, 30 grams of milk, sugar: 30 grams of egg white, 10 grams of egg yolk, 25 grams of oil (corn oil is best), 40 grams of low-gluten flour

1. Separate the egg whites and yolks. Make sure the bowl with the egg whites is dry, without water or oil. Add three to five drops of white vinegar to the egg whites (this will remove the egg smell) and put them in the refrigerator for later use.

2. Find another bowl, put oil, sugar and milk, stir well, then add low-gluten flour and continue to stir well. Finally, add egg yolk. This is the post-egg method. The cake will be very soft.

3. Take out the egg whites and beat them with an electric whisk. Prepare 30 grams of white sugar and set it aside. When the basin is full of big bubbles for the first time, add a little white sugar. There is no special requirement for the number of grams. Add a little at first and continue beating. When it is full of fine bubbles and the egg whites become more, add sugar for the second time and continue beating. Beat until there are lines and it becomes ivory white, then put all the sugar in and continue beating until the egg whites become thick. At this time, slow down the speed, stop the whisk from time to time, pick it up to check the state of the egg whites, and beat until there are big curved corners, then it is done.

4. Preheat the oven to 170 degrees. Use a spatula to scoop one-third of the egg white into the egg yolk and stir in a "Z" shape, or as long as it is not clockwise or counterclockwise, it will be fine. When the egg white is no longer visible, add the remaining half to the egg yolk and stir as before. Pour all the mixed batter back into the remaining egg whites and stir in the same way.

5. Line a square baking pan with baking paper, pour the batter in, shake it a few times to get rid of the bubbles, and bake in the oven at 170 degrees for 20 minutes.

6. When the cake base is cool, you can make the roll. Lay the cake base flat and apply butter or various jams on it. Apply it thickly so that it will be fuller when rolled up and have a better taste when rolled up with the cake base. Or you can just roll it up without applying anything and make a plain cake roll. Some people like to use a rolling pin to help roll it, but I like to roll it directly by hand, which is more solid. After rolling it up, wrap it tightly with wax paper and put it in the refrigerator for half an hour to set, then take it out and cut it into pieces and enjoy it.