In the baking world, chiffon cakes can be said to be entry-level. However, in the eyes of many cute newcomers, the chiffon cake has become a “crazy cake” in minutes: after nn rollovers, I was finally mad… Obviously it was made according to the cake recipe, why did it finally become Egg pie?
Accidentally turned into a quiche cake
Bread has the same problem. What about cellulite? How about crispy and soft? What is this steamed bun that looks like biscuits?
“Steamed buns” like biscuits
It can be said that cakes and breads are the art of air, 80% of the whole volume is air. By understanding the detailed principles and operating skills of air entering and retaining it, you will be one step closer to the “food molecule” and one step away from “overturning”.
There are three main means of aerating a batter or dough in life:
1. Biological means. When making bread, yeast is generally used to ferment and produce gas. Under the right conditions, yeast will break down a glucose molecule into two alcohol molecules and two carbon dioxide molecules, making the dough larger.
2. Physical means. Unlike bread dough, when making cakes, we use physical stirring to aerate the raw egg whites, or whip the egg whites.
3. Chemical means. Commonly used is baking powder, which is mainly composed of sodium bicarbonate (soda powder), cornstarch and acidic materials, which can generate large amounts of carbon dioxide when exposed to water and heated.
Cake: I was “beaten” and I was “angry”
The softness of the cake mainly comes from physical means of aeration, that is, by whipping the protein molecules in the raw egg whites to change, thereby fixing a large number of air bubbles.
When you crack open an egg, the raw protein inside will flow out quickly. This is because 90% of the protein is water, and the remaining 10% is protein.
Each protein molecule consists of tens to hundreds of amino acids, and the individual amino acids are linked together in long chains and then folded into a tight clump. Because of the accumulation of negative charges on the surfaces of individual proteins, they compress and repel each other, like clumps of wool floating in water, without interfering with each other.
When the egg whites are beaten, the tension will make the hit “wool balls” unfold, and the adjacent “wool yarns” will entangle with each other to form a “wool net”, that is, a protein net. A solid network blocks the flow of water and small air bubbles, keeping the whipped raw egg whites in shape.
In the era when there was no electric egg beater, it was still very time-consuming and labor-intensive to manually beat egg whites. For example, the famous dish of snow bean paste at the imperial banquet of the Qing Dynasty was almost lost. Nowadays, with the popularity of electric egg beaters, the biggest problem when people beat egg whites is not time-consuming and laborious, but that the egg white foam is unstable. There is enough air when it is just beaten, but it collapses when baking.
Just like the song sings: “Beautiful bubbles, although a flash of fireworks. All your promises, although they are too fragile…I should have known that bubbles will burst at a touch…”
How to avoid protein “getting out”
There are three main reasons for the instability of the bubble. One is that the formation of the protein network is disturbed, making it easy for air bubbles to escape. The second is that the “hug” between the proteins is too tight, squeezing out the water, resulting in a dry and rough texture of the protein foam and becomes granular. Third, even without the above problems, water will slowly escape over time, disintegrating the structure and causing defoaming.
Accordingly, in order to stabilize the fragile foam, we have these three types of methods that can be used.
Keep the protein clean
The point is that the egg whites to be beaten should be clean, ensuring no egg yolks, no oil, and no detergents. Because these substances will compete with proteins for air and water resources, they will not play a role in supporting the foam structure, and they will also interfere with the intertwining of protein molecules.
Therefore, in addition to ensuring that the container is clean, try to use fresh refrigerated eggs when choosing eggs to ensure that the yolk membrane is complete and the egg whites will not be mixed with yolks.
Add acidic substances, do not overbeat
Proteins make a lot of “dead knots” as they wind up in a web, and too many knots can make them “hug” too tightly and the foam collapses.
Too much knotting can squeeze out moisture and cause the foam to collapse
Increasing the acidity can greatly slow down the formation of “dead knots”. For example, fresh eggs are more acidic than old eggs that have been left for a period of time, so you need to use fresh eggs as much as possible to make cakes.
In addition, you can also add acidic substances, such as cream of tartar, lemon juice or white vinegar, to the egg whites before beating. The dosage is about 0.5 grams of cream of tartar and 2 ml of lemon juice per egg white.
Of course, over-whipping will also cause too many knots, so it is very important to learn to judge the status of whipping, and there are a lot of tutorials on the Internet. If you are still not sure… Then try it with a protein to see how it survives the “beaten” life. After the test, you can also spread out an omelette and eat it without wasting it.
egg whitening process
add sugar to lock water
To lock in moisture, the most common method is to add sugar, at least 10 grams per egg white. The liquid in raw egg whites becomes thick and sticky due to sugar, which greatly eases the escape of moisture and prevents defoaming. Entering the high-temperature baking stage, the dissolved sugar hugs the water molecules tightly and does not let go, slowing down the evaporation of water, allowing time for the egg whites to solidify, and turning the foam wall into a real iron wall.
However, it should be noted that adding sugar at the beginning of whisking will interfere with the unfolding of the protein “wool ball” and prevent foaming, so it should be added later. However, it is not enough to add sugar at one time at the end of the beating. On the one hand, the rough sugar particles will damage the formed protein network, resulting in a large area of defoaming. On the other hand, the large amount of sugar added at the same time is not easy to completely dissolve.
So we usually add sugar in three batches after foaming. At this time, most of the protein has been unfolded, but the network has not been fully formed. The sugar can stabilize the bubbles in the protein network to the greatest extent.
Knock on the key point, the effect of sugar on the cake is not only to increase the sweetness. For those who are afraid of fat and want to eat sugar-reduced cakes, they should be prepared for insufficient cake expansion (except for special recipes).
Of course, protein foam is not the only factor that determines the success of a cake. The ratio of water and oil, baking temperature, cooling method, etc. will all affect the final product. Therefore, try not to change the recipe privately when making cakes, and find the right temperature according to the temper of your own oven when baking. As for inversion cooling, using a hollow container can facilitate inversion (also increase the heating area and improve the success rate) and prevent the cake tissue from being squashed.
If there is only an ordinary container, it can also be sucked by an iron hook, but the premise is that the mold is not oiled, otherwise it will fall off…
gas in bread
How did it get into the dough?
Like cakes, the key to success in bread is the firmness of the structure that supports the air bubbles, and whether there are enough air bubbles.
Let’s do a multiple-choice question first:
When do air pockets in bread occur?
A. When yeast ferments or baking powder produces gas
B. When kneading the dough
C. When whipping egg whites
Unlike cakes, it is not the egg whites that support the structure of the bread, but the gluten in the flour, so the wrong answer C can be ruled out first. Flour is mainly composed of starch and gluten protein. The gluten protein content of more than 10.5% can be called high-gluten flour, which is suitable for making bread.
After adding water and kneading the dough, the independent gluten molecules in the dough will be connected end to end, and hundreds of molecules “hand in hand” form an ultra-long chain. These ultra-long chains have many twists and turns like telephone wire, and they entangle with each other, forming a disjointed network of gluten, in which the starch is embedded.
Protein ultra-long chains tangled like telephone wires
Kneading the dough makes it easier for gluten molecules to find “partners” to form long chains, and allows the scattered long chains to adjust their direction and become neat and orderly, forming a strong and stable gluten network that supports the bread tissue.
The “kneading out the glove film” often said in the bakery industry is a sign of the orderly arrangement of the gluten network.
At the same time, the kneading process will also bring air into the dough, forming small air pockets. Focus! In the process of proofing the dough by adding yeast or baking powder, no new air pockets are created, and the carbon dioxide produced will enter the existing small air pockets and then expand the volume of the large pockets. Therefore, the more air pockets are created when kneading the dough, the finer and softer the finished product will be.
So, did you just choose correct answer B?
Air bubbles are trapped in clumps of gluten and starch, giving dough a soft texture
Therefore, for most bread recipes, kneading is very important! It’s just a little bit labor-intensive (you can’t get down for ten or twenty minutes, and you can buy a chef machine if you like to make bread and feel tired).
Some people like to beat and knead the gluten protein “hand in hand”, this is also possible, but it is too loud, be careful not to be misunderstood by the neighbors that your family is fighting… But then again, this is also a kind of decompression a good way.
After kneading the dough, it is time to wait for fermentation. When the dough does not spring back when pressed, it means the fermentation is complete. This is because the dough rises during fermentation, and the helix of the protein chain like a telephone wire is pulled apart a little bit. When all the spirals are straightened, the gluten is stretched to the elastic limit, so it will not rebound when pressed, and if it continues to ferment at this time, it will only damage the gluten.
In addition to kneading and raising the dough, additives can also affect the gluten network. Salt, slightly alkaline water, and hard water containing calcium and magnesium will strengthen the gluten network and increase the volume of the finished bread. The oil can hinder the formation of the gluten network, so it is usually not added in the early stage of dough mixing.
All in all, in the recipes and recipes for making cakes and breads, when it is written, when to add this and when to add that, how to operate here and what to pay attention to, all of which are supported by physical and chemical mechanisms! Now, do you understand what happened to the flat omelettes and hard buns you made?
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