Soy milk, or soya milk, is an affordable, nutritious and easily digestible drink made from soya beans. It is rich in proteins, vitamins A, B1 to B12, C, and D, calcium, and other minerals. Hence, it is suitable for infants, children, pregnant and lactating women, the elderly, etc.
Contrary to most other protein foods, soy milk does not contain cholesterol and possesses fats (specifically saturated fats) in low quantity. It also contains a low amount of calories, which makes it suitable for dieters.
There are two different methods of making soya milk – traditional methods and modern methods. Modern methods include the Cornell method (also known as the hot grind method), the Illinois method (also known as the Pre-blanch method), Rapid hydration hydrothermal cooking, Direct use and Solvent Extraction method, etc.
Here is a simple traditional method of processing your soy beans into soy milk at home.
- Your desired quantity of soybeans
- Clean running water
- Sugar to taste (optional)
- A sizable container for soaking your soybeans. This should be big enough to contain the soybeans when it rises or swells.
- A Blender or grinder
- A Strainer, Organic Cotton Nut Milk Bags, or Cheesecloth such as fine-meshed Butter Muslin Cheesecloth.
- A Heavy-bottom Pot or Pan. This is necessary for the even distribution of heat and to prevent the burning or scorching of the pot or pan.
Note that: You can twist your homemade soya milk recipe to adapt to your taste and desire. You may decide to add salt, spices such as cocoa and cinnamon, your preferred fruit mix, flavors such as vanilla, and other sweeteners such as agave nectar, honey, maple syrup, etc.
Also, for optimum results, use yellow soybeans to make your soy milk.
Step-by-step Instructions on How to Make Your Soy Milk at Home
- Soak your soybeans over the night or for at least eight to ten hours to soften them. Another faster way to achieve this is to parboil it for at least 15 minutes.
- Wash the soybean out of the water and rinse with clean water to remove dirt and stones.
- Rub the soybeans against each other to remove the skin. Normally, the dehulled skin floats on water, and you can remove it by decantation or skimming. Dehull as much as you can. It is okay if you cannot remove all the skin.
- Put the soybeans into your blender or grinder and blend or grind to a smooth slush or paste.
- Strain or sieve the blended mixture with a nut milk bag or cheesecloth to remove the chaff or leftover fiber, known as okara or hara. Okara can be frozen or dried and reused for cooking or as a fertilizer.
- Transfer the strained milk to your heavy-bottom pot and cook at 100 °C or 212 °F for twenty minutes. However, if you are cooking with heat that does not specify temperature, cook under moderate heat for 60 – 90 minutes. Frequently stir the mixture while it cooks to avoid burning or sticking.
Remember to closely watch your soya milk while it cooks to avoid spilling over the pot and floor. Better still, leave the pot open.
- Cool the milk and add your preferred flavors, sweeteners, and fruits.
- Refrigerate and enjoy.
How to Store and Preserve Your Soy Milk
Soy milk is vulnerable to microbial attacks and spoilage because it contains rich nutrients that encourage the growth of these microorganisms. Such microorganisms include yeasts, molds, mesophilic aerobic bacteria, and coliforms such as E. coli, etc. are responsible for the spoilage of soya milk and other unpleasant changes in taste, smell, or consistency of the soy milk.
Hence, soy milk should be properly processed, and stored to prevent microbial invasion and spoilage.
Soy milk can be stored and preserved through the following means:
- When stored in a sealed container at room temperature (25 °C), it can stay up to two days.
- By storing in an airtight container and refrigerating it. Storing soya milk in the refrigerator can help maintain its optimal consistency, smell, and taste for at least seven to fourteen days.
- By adding preservatives such as potassium-meta-bi-sulfite (KMS), Sodium-benzoate, and potassium sorbate. These preservatives can be used separately or mixed together to preserve soy milk.
- By heating soy milk at 143 °C for 60 seconds.
- By employing ohmic heating, which is an advanced thermal processing technique that involves an electric current being passed through the soya milk to increase its shelf life.
- Soy milk can be presented by High-Pressure Processing (HPP), which is a non-thermal method that inhibits the activities of vegetative microorganisms that are responsible for soy milk spoilage.
- Soy milk can be preserved by Pulse Electric Field (PEF), which is another non-thermal method. It involves the use of short pulses of high electric fields for microseconds to milliseconds.
- Drying or dehydration of soya milk can help improve its shelf life and, as well as, ease transportation, and storage.
FREQUENTLY ASKED QUESTIONS ABOUT SOY MILK
1. How Long Does Soy Milk Last?
How long soy milk lasts depends greatly on the storage or preservative procedure adopted. Under room temperature, soya milk can last for a maximum of two days. If it is refrigerated, it can last for at least seven to fourteen days. However, the shelf life might increase if other preservative techniques are employed.
2. How Do I Know Spoiled Soy Milk?
There are many ways to tell that your soya milk is spoiled. Indicators include foul smell or odor, sour or stale taste, and irregular consistency (It could be too watery or too thick beyond the normal).
3. Can a Pregnant Woman drink Soy Milk?
Soy milk has no contraindications or adverse effects during pregnancy. Hence, it is suitable for pregnant women as long as it is well-processed and stored.
4. Can a Lactating or Nursing Mother Drink Soy Milk?
Soya milk is suitable for nursing mothers as long as it is properly prepared and preserved.
5. Can a Baby or Child Drink Soy Milk?
Anybody of any age group, including children and the elderly, can drink soy milk.
Does soy milk go bad?
Yes, soy milk does produce warning signs when it has spoiled, and it is vital to be able to identify rotten milk. One primary indicator that it has gone bad is the smell. Bad soy milk releases a foul or sour odor, similar to regular milk.
List of References
Kumar, S., Upadhyay, S., Mishra, R. and Kohli, D. (2017). Preservation and processing of soymilk: A review. Available at: https://www.researchgate.net/publication/330873335 [Accessed: 16th May 2023].