There are many reasons for the yellowing of steamed bread, but no matter which reason, there are three problems. Raw material problem, formulation process problem and equipment problem, Li Ji will talk about these three problems in detail, and the corresponding solutions. The reasons for the yellowing of steamed buns are basically in this article. This article can be used as a tool guide. When you encounter the problem of steamed stuffed bun yellowing, you can find the reason in this article, and then find the appropriate solution according to your actual situation. If you have any questions after reading this article, you can leave a message for Li Ji. After reading the message, Li Ji will reply to you.

Second, the problem of raw materials.

1. Flour problem

The whiteness of flour is the most important factor to determine the whiteness of steamed buns, and there is no one.

Theoretically speaking, the higher the processing accuracy of flour, the whiter the flour and the lower the pigment content. Generally speaking, the coarser the grain size of flour, the bigger the bran star and the yellower the color; The finer the grain size of flour, the smaller the bran star, the whiter the flour and the higher the brightness. So when we see that the flour particles are coarse, but the flour is white, we can basically judge that this kind of flour contains certain additives, and some flour mills also call it improver. The most important function of these modifiers is whitening.

Therefore, when making steamed stuffed buns, we should try to use flour with relatively high processing precision, and do not use flour with coarse flour particles to make steamed stuffed buns. What needs to be emphasized here is that some small flour mills will add whitening agents such as gypsum powder and talcum powder to the flour in order to reduce the cost. These whitening agents are allowed to be added in the old standard, but they are not allowed to be added in the new standard for the use of food additives. The steamed bread made of such flour tastes bad, and some chemicals are easy to exceed the standard.

There is another important point about the use of flour. It is very important to avoid making steamed bread with flour ground from new wheat. When many friends make steamed buns, the process and formula have not changed, but there are problems with the steamed buns, and the reasons can't be found. If this happens, many of them may use flour made from new wheat. This problem is hidden and not obvious, and it is easy to be ignored by many friends. In the video program of Li Ji, Li Ji said that the seventh issue of steamed stuffed bun has been launched, and interested friends can search it.

2. Water quality problems

Besides flour, the most used material for making steamed buns is water. China has a vast territory and rich resources, and the water quality in each region is different. In some areas, the water quality is alkaline, and steamed buns made with such water are prone to yellowing. If this happens, you can add some white vinegar to the water to neutralize the alkalinity in the water. In other areas, the water quality is not very good, and there are many impurities, or well water is used to make buns. In this case, it is best to filter before using water.

Three. Formulation and process problems

1. Problems in dough mixing technology

Theoretically speaking, kneading time is the core technology to control the formation of dough gluten. Too short kneading time, insufficient conditions for gluten formation, and too long kneading time will destroy the gluten structure of dough. In severe cases, there will be oozing inside the dough, and the dough mixing time is too short. The expired dough cannot reach the state suitable for gluten expansion, and the steamed bread will turn yellow.

On this issue, Li Ji once wrote an article called: Do you have to wake up to make steamed buns? Can you wake up soon, or even not? Interested friends can have a look. This paper expounds the conditions of gluten formation and the influence of gluten formation on subsequent steamed stuffed bun making.

2. Pressing the surface problem

The purpose of dough pressing is to make the bubbles in dough disappear and form a compact hierarchical structure, which is beneficial to the subsequent proofing process to produce uniform pores. If the dough is not pressed enough here, the air in the dough cannot be completely removed and the holes are not fine enough. When the dough is fermented again, the inside of the steamed bread is not uniform enough and the steamed bread will turn yellow. Therefore, Li Ji suggested that the general pressing time should be around 8- 10 times, and the pressing times should not be too much or too little.

3. Wake-up time is too long

If it takes too long to wake up, the noodles will be sour and the buns will turn yellow. Everyone basically understands this. If the dough proofing takes too long, it can be neutralized with alkali; If it takes a long time to proofe steamed buns, you can put baking soda in advance when pressing dough, which can not only solve the problem of too fast fermentation, but also neutralize the sour taste caused by proofing to a certain extent, and also play a whitening role.

4. The humidity is too high

Theoretically, the proofing humidity should be controlled between 60% and 75%. If the humidity is too high, the oxygen in the air will combine with the surface of steamed bread to form an oxide layer, which will make steamed bread yellow. Li Ji suggested that you can buy a thermometer to measure the temperature around your hair. If the humidity is too high, reduce the humidity appropriately.

5. How to use alkali?

Theoretically, the pH of dough has a great influence on the quality of steamed stuffed bun. Li Ji once bought a pH tester and pH test paper for experiments, and wrote an article called "The process of adding alkali to old steamed bread can be standardized in this way. When the pH value of dough is around 6. 4. Steamed buns have the best effect, the best state and the whitest. When the pH value of dough increases with the increase of alkali content, and the dough gradually becomes alkaline, the color of steamed stuffed bun begins to turn dark and yellow, because the alkaline environment affects the fermentation of yeast in dough. Li Ji has this conclusion in the experimental article. Interested friends can have a look at the specific experimental steps.

So the dosage and usage of alkali are very important. In Li Ji, the general method is to melt alkali with water and then gradually mix it into flour. The main purpose of this is to add the alkali several times, and mix the alkali with the dough fully every time, otherwise it will be spent.

6. The dosage and method of baking powder

Because baking powder is an alkaline substance, too much baking powder will turn yellow. When using baking powder, be sure to mix baking powder and flour evenly before stirring; If baking powder is added when pressing the surface, remember to knead it evenly before molding, otherwise yellow spots will appear.

7. The steaming time is too long

When steaming steamed bread, the longer the steaming time, the yellower the steamed bread will be, because the starch in the flour will react with the air, which will lead to the yellowing of steamed bread. Li Ji suggested shortening the steaming time as much as possible, on the one hand, to save fuel costs, on the other hand, to ensure the quality of steamed buns.

8. Add too little water

This reason usually occurs in primary fermentation or fast-growing noodles, because secondary fermentation or long-term fermentation will produce water, so it is not obvious that steamed bread turns yellow because of too little water.

If too little water is added, the dough will dry and harden. If the dough proofing time is short, it is difficult for the pores inside the steamed stuffed bun to reach a delicate and uniform state, and the rough pore structure will lead to black spots. Accordingly, higher water addition will promote the proofing of dough, which is a fine and uniform air hole state in dough or steamed stuffed bun, further increasing the reflection of light and making steamed stuffed bun look white.

Fourth, the equipment problem.

1. The steamer, steamer and drawer cloth are not clean.

If the steamer is not cleaned, there may be water drops or even stains during steaming, and there may be water drops or other things on the surface of steamed buns. When this happens, Li Ji suggested that the cleaning equipment must be cleaned and wiped clean. When cleaning equipment or tools, try not to use alkaline cleaning solutions, such as soda ash, washing powder and decontamination powder. Try to use neutral ones. When steaming steamed bread with drawer cloth or straw mat, brush oil as little as possible or not, because brushing oil too much will make the bottom of steamed bread yellow.

2. The resistance of the steam pan or steamer to steam is too large, resulting in too high steam pressure.

Many friends do not pay attention to this. Many friends asked Li Ji why my steamed bread was always raw and steamed for a long time. Perhaps this is the problem, and this problem will also lead to the yellowing of steamed buns. When we steam steamed bread, there may be too much resistance to the whole dish or steamer or non-porous steaming. Some friends like to spread several layers of straw mats when steaming steamed bread, and then spread silicone cloth. In this case, the air pressure in the steamer or steamer will increase, and the steamed bread skin will be burned, which is a bit like burning. In this environment, steamed bread is likely to appear hot spots and turn yellow locally.

V. After editing

These problems are basically unavoidable when the steamed stuffed bun turns yellow.

Too much alkali, too short to wake up.

Too much alkaline noodles will turn yellow.

Steamed bread and steamed buns are essential staple foods in northern China. But why does steamed bread or steamed bread occasionally turn yellow?

The baking powder used in traditional steamed bread is always added at the later stage of kneading, which often leads to the reaction of baking powder.

Incomplete, the alkaline substance of baking powder will cause the steamed stuffed bun skin to turn yellow. Using old flour fermentation technology will encounter the problem of steamed stuffed bun yellowing. This is mainly because there are not only yeasts in the dough, but also many miscellaneous bacteria (such as lactic acid bacteria). After the dough is fermented, it needs to be neutralized with alkali. If the amount of alkali is too large, steamed bread will turn yellow and taste alkaline.

The quality problem of flour, some flour mills grind the flour too fine in order to pursue the whiteness of flour, which leads to the fragmentation of starch particles. When this kind of flour is used on steamed bread, there will be a double-color problem that steamed bread is white and shiny when it is just cooked, but it will turn yellow after a period of time.

First, the skin color of steamed stuffed bun is yellow and black.

Bean cake analysis:

1. Flour is not white.

2. The water quality is poor and yellow.

3. The dough is not fully kneaded or squeezed.

4. The humidity is too high when you wake up.

Bean cake action:

1. Choose whiter noodles. The original whiteness of flour basically determines the whiteness of steamed buns.

2. See if your water pipe is rusty. It is best to use stainless steel water pipes. Well water is yellow and contains a lot of impurities. You'd better filter the water before using it. The water here is yellow. Fortunately, there is a water dispenser next to us. I bought a filter element and filtered it before coming out. )

3. To ensure the number of dough pressing, I usually press the dough about 8- 10 times (this figure is a reference value, please refer to the Causes and Solutions of Steamed Buns and Steamed Breads for the specific degree of dough pressing).

4. Under the premise of ensuring no cracking, reduce the humidity to make the steamed bread skin soft and non-sticky. Generally, the humidity is controlled between 60% and 75% (if there is a proofing box, it is simple. If not, I suggest you buy a thermometer to measure the temperature around the proofing and control it appropriately.

Second, there are yellow spots on the skin of steamed buns.

Bean cake analysis:

1. Too much alkali.

2. When alkali is released, the alkali powder does not melt with water.

3. The yellowing of the bottom may be due to too much brush oil or too heavy oil color.

4. The surface is partially yellow, which may be caused by alkaline liquid dripping on it or the items that come into contact with steamed bread are alkaline.

5. There is also a situation called "browning", which generally occurs in the process of "re-steaming". You can download the specific meaning of "browning", and we will talk about it in detail when we have the opportunity.

Bean cake action:

1. Reduce the amount of alkali added, and then add it after the alkali is completely dissolved. How and why to add alkali can be seen in two other articles written by Li Ji. Baking powder is also an alkaline substance. Too much baking powder is yellow and bitter. When using, if baking powder is used when mixing flour, you must mix baking powder with flour before mixing flour. If you add baking powder when pressing powder, remember to press it evenly and then squeeze it, otherwise there will be yellow spots.

2. Avoid contact with alkaline substances.

3. When cleaning equipment, containers, mats and covers, alkaline cleaning solutions, such as soda ash, washing powder and decontamination powder, are not needed.

4. Choose a light-colored oil brush bowl, brush it as little as possible or not, and it is not sticky.

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