How to use a yogurt machine to make yogurt
1. Sterilize the container of the yogurt machine with boiling water. People often overlook this problem or think it is not important. In fact, if this step is not done, it will easily affect the effect of the yogurt. Bacteria are cleaned up.
2. Selection of strains, commonly used strains include pure yogurt and yogurt starter.
It is more common to use pure and original probiotic yogurt as the fermentation source. To check the production date in detail, the closer the better; milk) into the yogurt machine, remember to stir well, and then plug in the power.
Or yogurt with appropriate amount of bacteria powder and stir well. (Generally, the amount of bacteria powder will be indicated on the bag)
3. Set the fermentation time. Generally speaking, when pure yogurt is used as the fermentation source, the fermentation time is about 6-8 hours. If you use yogurt starter When used as a fermentation source, it takes about 8-12 hours, but it will be affected by the surrounding temperature. If the temperature is too low, it will take longer. However, it is best not to use pure yogurt as a fermentation source for more than 10 hours. , When using yogurt starter as a fermentation source, it is best not to exceed 14 hours.
4. After the set time, check the yogurt, if it is solidified, it proves that it has been made successfully.
5. Put the finished yogurt in the refrigerator for 24 hours, and the flavor will be better. Of course, you can also add seasonings, honey, Juice, sugar, etc. are good.
Frequently asked questions about making yogurt with a yogurt machine 1. What is the basic principle of homemade yogurt? -42 degrees) to multiply and decompose the lactose in milk into lactic acid. Because of the lactic acid, the acidity of the milk fermentation broth gradually decreases, and when the pH value reaches about 4.6, the casein in the milk will slowly settle down to form a delicate jelly. Although other miscellaneous bacteria also exist in milk, their number is too small compared with lactic acid bacteria to form a climate. The lactic acid and other antibacterial substances produced by lactic acid bacteria also make the bacteria feel very uncomfortable and cannot reproduce in large numbers. This ensures the safety of the yogurt.
2. Can I use a yogurt machine?
It is best to use a yogurt machine for making yogurt at home. Because it can provide a stable temperature, it must be the target lactic acid bacteria, not other miscellaneous bacteria, that ensure vigorous reproduction. The temperature of the yogurt machine is 40-42 degrees Celsius, which is exactly the optimal breeding temperature of Lactobacillus bulgaricus and Streptococcus thermophilus used to make yogurt. The suitable breeding temperature for most pathogenic bacteria is 20-37 degrees Celsius, and they do not like high temperatures above 40 degrees. If the temperature difference is large, the reproduction of miscellaneous bacteria may increase and the safety will decrease.
3. It is better to use mushroom powder or yoghurt for household yogurt machine. When using bacteria powder, freeze-dried bacteria are added, and they can “wake up” to function in a warm environment. When using commercially available yogurt, you must pay attention to buying the latest refrigerated yogurt, because with the extension of storage time and the rise of storage temperature, the number of viable bacteria will continue to decline, which will affect the effect of making yogurt. It must be noted that those yogurts sold at room temperature should not be used for seeding, because they are either sterilized and cannot provide viable bacteria, or the number of viable bacteria has been severely reduced, and the safety of making yogurt cannot be guaranteed.
4. Is it okay to buy bacteria powder to buy health bacteria?
The basic requirement for yogurt production is to have enough Lactobacillus bulgaricus (L) and Streptococcus thermophilus (S), so just buy two kinds of basic bacteria powder. Other health-care bacteria, such as Lactobacillus acidophilus (A), Bifidobacterium (B), some strains of Lactobacillus casei (C), etc., have been proven to have health benefits if they can colonize the human large intestine. However, if the benefits of these bacteria are required, the premise is that there is a sufficient number of viable bacteria after fermentation.
However, the optimum fermentation conditions for these bacteria are not necessarily the same as the two basic bacteria mentioned above. In particular, bifidobacteria are strictly anaerobes, that is, they die at the sight of oxygen. Therefore, it is difficult to obtain live bifidobacteria in the yogurt making process of ordinary families. Therefore, there is no need to expect too much of the health-care bacteria in the strain.
5. How much is appropriate to use yogurt to make yogurt?
Generally speaking, it is more appropriate to add about 10% of commercially available yogurt as a strain. For example, to ferment 500 grams of milk, 50 grams (half a cup of yogurt) is enough. This amount is to allow lactic acid bacteria to establish an absolute quantitative advantage from the beginning, and to have sufficient ability to suppress various other miscellaneous bacteria. Even inexperienced people can ensure the success of yogurt production. In industrial production, because the operation is relatively standardized, the vitality of the bacteria is relatively strong, and the amount of bacteria used accounts for 1-2% of the milk to be fermented.
6. Can the prepared yogurt be used for seed fermentation?
If you use the purchased strain to make your own yogurt, you can use it for two or three times of strain fermentation. If you use the yogurt from the market for seed , can be used up to one or two more times. If you want to increase the frequency of use and reduce the production cost, the premise is that the operation of making yogurt is sufficiently standardized, and at the same time, the quality of the homemade yogurt used for seeding must be high enough.
When using the last yogurt as a strain, you need to pay attention, the yogurt must taste pure and fresh enough. The pure taste shows that there is no contamination of too many other miscellaneous bacteria, and the vitality of the bacteria in the yogurt that is moderately fermented, refrigerated in time, and has not been stored for a long time is still relatively high. If the fermentation is too long, or if it is not refrigerated in time, or if it is refrigerated for too long, the number of live lactic acid bacteria in the yogurt will decrease. If you find that the yogurt tastes like alcohol, or has a slight musty smell, it means that it has been contaminated with a lot of bacteria and must not be used anymore.
7. Does the milk need to be heated in advance when making yogurt?
Before making yogurt, if it is not the milk that has just been poured out of the sterilized Tetra Pak bag, it is best to heat the raw milk to 60-80 degrees, not boiling but can kill most bacteria, and then drop to more than 40 degrees (the hand feels a little hot, but it does not feel uncomfortable), and then inoculate. The box for making yogurt and the spoon for adding bacteria should also be scalded with boiling water, or put a spoonful of water in the cup or box for making yogurt, turn it in the microwave, and use hot steam to kill the microorganisms on it to minimize chance of contamination by bacteria.
8. Why the coagulation speed and taste of yogurt are different with different milk
If the same strain is used To make yogurt, the amount of bacteria is the same, so the coagulation of yogurt depends on the growth rate of lactic acid bacteria and the content and quality of protein in milk.
Also compared in the state just frozen, when the protein content of milk is high and the molecular weight is large, the yogurt produced is more “firm” and thicker; on the contrary, the protein content of milk is too low , or the molecular weight is small, the freezing state will be more fragile, or even unable to freeze. The molecular weight of milk protein is originally very large. If the molecular weight becomes smaller, it is usually because the content of microorganisms in the raw milk is too high, and the protease secreted by the microorganisms will also be too much. If there are too many antibiotics in the milk, it is difficult for the lactic acid bacteria to multiply rapidly, so the yogurt will freeze slowly or even difficult to freeze.
So, in a sense, a milk (regardless of the addition of thickeners) to make yogurt quickly and with a good consistency is a satisfactory quality.
9. Can you use milk powder to make your own yogurt?
Milk powder plus water is reconstituted milk, which can be used to make yogurt. The premise is that the amount of water added is appropriate, about 7 parts of water should be added to one sugar-free pure milk powder, and the fermentation can be successful by adding bacteria like ordinary milk. As long as high-quality milk powder is used, the quality of the finished yogurt is not inferior to that of ordinary fresh milk products.
It should be noted that sweet milk powder contains a lot of sugar, which dilutes the protein content, so it is necessary to add less water to make the protein content reach the level of pure milk before making yogurt curd. Generally speaking, 1 portion of sweet milk powder plus 4-5 times of water is enough. The specific ratio can be determined by the protein content of the product. For example, if the protein content of milk powder is 18%, then 1 serving of milk powder plus 5 times of water will have a protein content of 3%, which is exactly the same as ordinary milk.
The protein content of ordinary infant formula milk powder is lower than that of ordinary milk, but the lactose content is much higher. If you add water like ordinary milk powder, you cannot make qualified yogurt. Therefore, the amount of water added should be reduced to one-third of the amount when feeding the baby. Due to the high lactose content, the resulting yogurt will be a bit more sour. The protein content of milk powder for older babies over one year old is close to that of ordinary milk, so it can be used to make yogurt with a little less water.
10. How to make low-fat yogurt
Low-fat yogurt is easy to make, just use skim milk powder or low-fat milk as raw material, and add bacteria to ferment normally. Lactic acid bacteria are very suitable for low-fat life. If you want to add other unsaturated fats, there is no problem. For example, when making yogurt, add almond oil, olive oil, flaxseed oil, etc. to the low-fat milk raw material and stir well, and then all can be fermented normally.
11. Can you make yogurt without adding sugar?
In theory, there is no need to add sugar to make yogurt. It’s just that the yogurt produced in this way has a very sharp lactic acid taste, which is unacceptable to most people. Generally speaking, fermentation is complete as long as the yogurt is solidified. Many people leave yogurt there to ferment for more than ten hours, because the fermentation time is too long, the amount of acid production is too much, and the sour taste will be stronger. Adding sugar can balance the sugar-acid ratio and make the taste sweet and sour. However, because adding sugar will reduce the health value of yogurt and increase the calorie value, it is usually recommended to add as little sugar as possible, so that the sour taste of yogurt is less uncomfortable, and it can be eaten. The yogurt on the market usually has a sugar content of 7-10%, while the sugar content of home-made yogurt can be as low as 3-4%, which can be eaten by people. There are even a few people who can afford completely unsweetened yogurt, which is sold in many countries.
In the process of making yogurt, lactic acid bacteria do not decompose sucrose, they only decompose lactose. Therefore, adding sugar to the raw milk first and then fermenting it will not reduce the sweetness after it is made.
In order to make the yogurt have a nice sweetness without eating too much sugar, one solution is to add chopped dried fruit directly. Because dried fruits contain as high as 60-80% sugar, they also contain a lot of healthy ingredients such as potassium, iron, dietary fiber and antioxidants. From a health perspective, it is much more cost-effective than adding sugar to sweeten them.
12. Why does the yogurt you make by yourself produce yellow water after two days?
When the yogurt is over-fermented, the freezing will shrink, and yellow water will easily appear. During the storage process, there will also be cases of continuous shrinkage and deformation of freezing, and the continuous seepage of yellow water. This yellow water is called “whey”, and the whey protein powder used by athletes to build muscle and the whey powder used to formulate infant formula is extracted from the whey. It is non-toxic and harmless, and in addition to containing easily absorbed protein, it is also rich in calcium and vitamin B2. In fact, the yellow color is due to the richness of vitamin B2. So, be sure not to throw away the yellow water.
13. How to store the homemade yogurt after it is made
It is best to keep the homemade yogurt in the refrigerator in time. If you can’t eat it all at once, use a clean spoon to scoop out part of it each time, and keep the rest in the refrigerator Among them is good. The recommended storage time is no more than 3 days. With the prolongation of storage time, the gel will continue to shrink, whey will be precipitated, and the taste will gradually deteriorate.
In fact, during the fermentation process of yogurt, there is a process of coagulation. When it is just solidified, the texture of yogurt is the most delicate and the surface is extremely flat. When scooped up with a spoon, the texture is relatively viscous. If you continue to keep warm and fermented after solidification, you will find that the surface of the yogurt has water, or there are small depressions, the texture will become less delicate, the sour taste is too strong, and the total number of viable bacteria will gradually decrease. Therefore, when making yogurt, you should pay attention to opening and observing it several times. As long as it solidifies, you should take it out in time and put it in the refrigerator. Refrigeration overnight will thicken the aroma of yogurt, because although the microorganisms stop producing acid at low temperature, they will produce aroma substances that make the yogurt more delicious than when it was freshly prepared.
