How do you get reduced fat milk? The industrial and at-home process explained

December 28, 2025 •

4 min read

Over half of milk sold in some regions is reduced-fat or skim, a clear indication of its popularity. But many wonder, how do you get reduced fat milk in the first place? It’s not by adding water, as a common myth suggests, but through a mechanical process that separates the cream from the milk. This guide will demystify the methods used both commercially and at home.

Quick Summary

The production of reduced fat milk is a mechanical process primarily involving centrifugal separation in factories. Simple methods can also be used at home to achieve a lower fat content.

Key Points

Centrifugal Separation: The primary industrial method for producing reduced fat milk involves spinning whole milk at high speeds to separate the lighter cream from the heavier, fat-free milk.
Not Watered Down: A common myth suggests that reduced fat milk is just whole milk with water added. In reality, the process physically removes the fat, not dilutes the product.
Fortification is Key: Since fat-soluble vitamins (A and D) are removed with the cream, commercial reduced-fat milks are fortified to ensure they have similar nutritional value to whole milk.
DIY Skimming is an Option: For an at-home method, you can manually skim the cream that rises to the top of whole milk after it has settled and been refrigerated.
Nutritional Consistency: All types of cow's milk (whole, 2%, 1%, skim) contain the same 13 essential nutrients, with the main difference being calories and fat content.
Taste and Texture Differences: The reduction of fat significantly impacts the milk's flavor and texture; whole milk is creamy and rich, while skim milk is much lighter.

Understanding the Milk Fat Separation Process

The fundamental difference between whole, reduced-fat (2%), low-fat (1%), and fat-free (skim) milk lies in their fat content. Whole milk, straight from the cow, contains about 3.25% fat. All other varieties are created by removing a portion of this fat. The process is not about watering down the product, but rather a precise and controlled mechanical separation, followed by standardization and fortification.

The Commercial Centrifugal Separation Process

In modern dairy plants, the primary method for producing reduced fat milk is a high-speed mechanical process called centrifugal separation. This method is far more efficient and sanitary than traditional manual skimming. The steps are as follows:

Milk Collection: Raw, whole milk is collected from dairy farms.
Heat Treatment: Before separation, the milk is heated to an optimal temperature of around 45°C (113°F). This warming helps facilitate a more efficient separation process.
Centrifugal Force: The warmed milk is fed into a centrifugal separator, a machine that spins the milk at extremely high speeds, ranging from 6,000 to 10,000 revolutions per minute (rpm).
Density Separation: Due to centrifugal force, the heavier, fat-free milk (skim) is pushed to the outer edges of the spinning drum, while the lighter cream (containing the fat globules) is forced towards the center.
Standardization: The separated skim milk and cream are collected in different streams. To produce reduced-fat, low-fat, or other varieties, the correct amount of cream is mixed back into the skim milk to achieve the desired fat percentage (e.g., 2% or 1%).
Fortification: During the skimming process, fat-soluble vitamins, primarily A and D, are removed along with the cream. To ensure the nutritional value remains consistent, the milk is fortified with these vitamins.
Pasteurization and Homogenization: The standardized milk is then pasteurized to kill harmful bacteria and homogenized to break down the remaining fat globules so they remain evenly dispersed throughout the milk, preventing a cream layer from forming at the top.
Packaging: The finished product is packaged and sent to stores.

Can You Make Reduced Fat Milk at Home?

While you can’t replicate the industrial centrifugation process in your kitchen, you can reduce the fat content of whole milk using simpler, traditional methods. These are not as precise but can work for certain recipes or preferences.

The Settling and Skimming Method: This method relies on gravity to separate the fat. Simply pour whole milk into a shallow, wide container and let it stand undisturbed in the refrigerator for at least 12-24 hours. The cream will naturally rise to the surface and form a distinct layer. You can then use a large spoon or ladle to skim the cream off the top. This will leave you with a milk that is lower in fat, although the exact percentage is unknown.
The Dilution Method (for cooking/recipes): For some culinary applications, you can create a lighter milk by simply diluting whole milk with water. A common ratio is combining 3/4 cup whole milk with 1/4 cup water to simulate a 2% milk, lowering both the fat and calorie content. However, this also slightly reduces the concentration of other nutrients and will result in a less creamy taste.

Comparison of Milk Types

To better understand how reduced fat milk compares to its counterparts, consider this nutritional table based on an 8-ounce (approx. 240ml) serving.


Nutritional Fact	Whole Milk (3.25%)	Reduced-Fat Milk (2%)	Low-Fat Milk (1%)	Fat-Free (Skim) Milk
Calories	~152	~122	~106	~84
Total Fat	8 g	5 g	2 g	0 g
Saturated Fat	5 g	3 g	1 g	0 g
Protein	8 g	8 g	8 g	8 g
Calcium	306 mg (25% DV)	309 mg (25% DV)	310 mg (25% DV)	325 mg (25% DV)
Vitamin D (fortified)	2.39 mcg (10% DV)	2.77 mcg (15% DV)	2.61 mcg (15% DV)	2.71 mcg (15% DV)
Vitamin A (fortified)	80 mcg (10% DV)	203 mcg (25% DV)	143 mcg (15% DV)	157 mcg (15% DV)

Conclusion: Choosing Your Milk Wisely

Whether produced commercially via centrifugal separation and fortification, or manually separated at home, the way you get reduced fat milk is a matter of science. The industrial process is highly controlled and efficient, ensuring consistent nutritional value and safety. While simple home methods exist, they are less precise and may not yield the same results. All types of cow's milk offer the same 13 essential nutrients, with the main trade-offs being fat content, calories, and taste. Your choice ultimately depends on your nutritional goals, dietary preferences, and intended use, whether for drinking, cooking, or baking.

When considering your options, remember to read the nutritional labels to understand the precise fat content and look for added vitamin fortification, which ensures you receive the essential nutrients present in whole milk.

To learn more about the nutritional science of dairy and its health implications, visit the Harvard T.H. Chan School of Public Health website.

Frequently Asked Questions

No, this is a common misconception. Reduced fat milk is made by removing the fat through a mechanical process called centrifugal separation, not by adding water.

Factories use a centrifugal separator. This machine spins the milk at high speeds, using centrifugal force to separate the lighter cream from the heavier skim milk.

The cream that is separated from the milk is collected and used to make other dairy products, such as butter, cream cheese, or sour cream.

Yes, they are. Since fat-soluble vitamins A and D are removed with the cream during separation, these vitamins are added back to reduced-fat and skim milk to ensure the nutritional content remains consistent.

You can manually get reduced fat milk at home by refrigerating whole milk until the cream rises to the top and then skimming it off. For cooking, you can also dilute whole milk with water.

Aside from the fat content and associated calories, all types of cow's milk contain the same 13 essential nutrients like protein and calcium. Reduced-fat versions are fortified to replace the vitamins lost during fat removal.

The primary difference is the fat content. 2% milk contains 2% milk fat by weight, while 1% milk contains 1% milk fat. As a result, 1% milk has fewer calories than 2% milk.