Do Soybeans Produce Milk? The Facts Behind this Plant-Based Beverage

November 28, 2025 •

4 min read

While a cow naturally produces milk, a soybean does not; the “milk” is actually a manufactured plant-based emulsion created through a process of soaking, grinding, and filtering soybeans with water. This popular beverage has been a staple in East Asian cuisine for over 2,000 years.

Quick Summary

Soy milk is a manufactured beverage created by grinding and filtering soaked soybeans, not a product the plant produces naturally. It is a high-protein, cholesterol-free dairy alternative enjoyed worldwide.

Key Points

Manufactured, not produced: Soy milk is a processed beverage, not a substance the soybean plant produces naturally.
The production process: Making soy milk involves soaking, grinding, heating, and filtering soybeans with water.
Nutritionally comparable: Fortified soy milk can offer a similar protein and calcium content to cow’s milk, while being cholesterol and lactose-free.
Dispelling myths: Scientific evidence does not support claims that moderate soy consumption negatively affects hormones in men, causes breast cancer, or harms the thyroid.
Functional name: The term "soy milk" is a Western name that reflects its use as a dairy substitute rather than its biological origin.
East Asian origins: This plant-based beverage has been a dietary staple in East Asia for thousands of years, predating its rise in popularity in Western countries.

Do Soybeans Naturally Produce Milk?

Contrary to the name, soybeans do not produce milk in the biological sense that mammals do. Soy milk is a plant-based beverage that is manufactured from the extraction of whole soybeans. The liquid is an aqueous extract that has a milky appearance due to its stable emulsion of oil, water, and protein. This process has been refined over centuries, with its origins traced back to China over 2,000 years ago, as an intermediate product in the manufacturing of tofu.

The Manufacturing Process: From Bean to Beverage

The journey from a small, dry soybean to a creamy liquid involves several key steps. Both traditional and modern methods follow a similar core sequence of hydration, grinding, and separation to create the final product.

The Modern Soy Milk Production Process:

Sourcing Raw Materials: High-quality soybeans, often chosen for a more neutral flavor profile, are cleaned and blended. Water and steam are also key components.
De-hulling: The soybeans are steamed and split to loosen and remove the outer hulls.
Enzyme Inactivation: The de-hulled beans are pressure-cooked with hot water to counteract an enzyme that makes them indigestible. This step also eliminates the undesirable “beany” flavor.
Grinding: The cooked beans are ground, first coarsely and then more finely, with added water to form a milky slurry.
Extracting: A centrifuge separates the liquid soy milk (called jun) from the insoluble soy fibers, known as okara.
Blending and Fortifying: The jun is mixed with other ingredients, such as vitamins (like D and B12), minerals (calcium), and flavorings (vanilla, chocolate, sugar).
Sterilizing and Homogenizing: The liquid is sterilized at high heat to ensure safety and extend shelf life. It is then homogenized, a process that uses pressure to break down fat particles and create a smooth, uniform texture.
Packaging: The finished soy milk is aseptically packaged in sealed containers to prevent contamination.

Nutritional Comparison: Soy Milk vs. Cow's Milk

One of the main reasons for the popularity of soy milk is its nutritional profile, which is remarkably similar to cow's milk when fortified. However, there are some key differences that are important for consumers to understand.


Feature	Fortified Soy Milk	Cow's Milk (2%)	Difference	Key Takeaway
Protein	~7-8 grams per cup	~8 grams per cup	Comparable	Soy is a strong plant-based protein source.
Fat	~4-5 grams per cup	~5 grams per cup	Similar	Varies by brand and type.
Cholesterol	0 grams	~20 mg	Cholesterol-free	Heart-healthy alternative.
Calcium	Often fortified	Naturally occurring	Varies by fortification	Choose a fortified brand for similar calcium levels.
Lactose	Lactose-free	Naturally occurring	Lactose-free	Ideal for those with lactose intolerance.

Debunking Common Soy Milk Myths

Despite its long history and scientific backing, soy milk is still subject to a number of misconceptions, particularly concerning its health effects.

Myth: Soy negatively impacts male hormones. Soybeans contain phytoestrogens, which are compounds that can mimic estrogen's structure, but extensive research has found no credible evidence that moderate soy consumption alters male hormone levels or fertility.
Myth: Soy increases the risk of breast cancer. Numerous studies have shown that high soy consumption is actually associated with a lower risk of breast cancer and a better prognosis for survivors, not a higher risk.
Myth: Soy is bad for the thyroid. The idea that soy consumption negatively affects thyroid function is largely based on outdated research. While soy does contain goitrogens, the effect is not significant in individuals with adequate iodine intake.

For more information on the processing of soy milk, you can review technical documents, such as those related to production standards and processes from organizations like the Small Industries Service Institute.

Why the Name “Soy Milk”?

The term “soy milk” is a Western adaptation, as in its country of origin, China, it is traditionally called doujiang, or “bean broth”. The widespread use of the term “milk” in the West led to court battles that ultimately established plant-based “milks” as a distinct food category. The name reflects its functional role as a milk substitute in cooking, baking, and as a beverage, rather than its biological origin.

Conclusion

Soybeans do not naturally produce milk, but are instead a raw material from which a liquid is extracted and processed to create the popular plant-based beverage. The multi-step manufacturing process involves soaking, grinding, heating, and filtering to create a safe and palatable product. Fortified soy milk offers a nutritional profile comparable to cow's milk, making it an excellent alternative for those with lactose intolerance or those following a vegan diet. Moreover, many of the common health concerns surrounding soy have been scientifically debunked, solidifying its place as a nutritious and versatile food.

Frequently Asked Questions

The white liquid comes from extracting the fluids from soybeans that have been soaked and ground with water. It is a manufactured emulsion of oil, protein, and water, not a natural secretion.

Whether soy milk is healthier depends on individual needs, but fortified versions offer a similar nutrient profile to dairy milk, with comparable protein and added calcium. It is naturally lactose-free and cholesterol-free.

No, soy milk is a plant-based beverage and does not contain any dairy or animal milk. It is a completely lactose-free and vegan product.

No, this is a common myth. Phytoestrogens in soy do not mimic human estrogen strongly enough to have an effect on male hormone levels, even with moderate to high consumption.

No, research suggests the opposite. Multiple studies have linked moderate soy food consumption with a reduced risk of certain cancers, including breast and prostate cancer.

Soy milk is generally higher in protein and calories than almond milk, making it a more nutritionally complete substitute for cow's milk. Almond milk is typically lower in calories but also contains very little protein.

Okara is the name for the insoluble fiber residue left over after the soy milk has been extracted during the manufacturing process. It is often used as a high-fiber, high-protein animal feed.