How is Milk Made? From Cow to Table #InternSarah


Have you ever wondered to yourself “how is milk made”? Have you ever thought about how milk gets from the cow to your table?

milk processing

Intern Sarah here! Last summer at my other internship my knowledge on dairy, specifically on the processing side grew exponentially. I was the sales and marketing intern at Sassy Cow Creamery in Columbus, WI. Pretty close to every morning, I was at the farm giving a tour for a field trip, and  pretty much every afternoon, I walked through the plant to fill an order or restock our store. Weekly, I was in grocery stores that carry our product checking how things are going and conversing with some of our customers. On a daily basis, I saw the entire milk process from start to finish.

How is milk made?

It all starts with the cows and quality feed (Read more about feed HERE). For a cow to be able to produce milk she must first have a calf. Once a cow has had a calf she can start to be milked. Most farms milk their cows twice a day, some farms will milk three times a day. (On Carrie’s farm and Sassy Cow Creamery, the cows are milked twice a day.)

How cows are milked
Two workers at Sassy Cow cleaning the cows udders and attaching the milking machine.

Milk on the farm-

When it is milking time, the cows will head over to the parlor. Different farms have a little bit of a different system for milking, but in general the cows will enter the parlor and get into a stall. The farmer will clean off the udder and apply a “pre-dip” (normally an iodine solution) to each teat. Then the farmer will dry off the teat and milk them some by hand, this is also known as stripping. It is done to promote the release of oxytocin, a hormone that promotes milk let down. It also is done to ensure that the milk is normal. Then the milking machine will be attached.

how cows are milked
Cows waiting on the parlor as they are milked.

On average it takes 5-7 minutes for a cow to be milked depending on how much milk she is producing. When she is done being milked the milking machine will automatically detach. The final step is the “post-dip” when the teats are again dipped in iodine to protect them from bacteria when they go back to the barn. The cows then will head back to the barn to enjoy a day of eating and sleeping.

Once the milk is out of the cow, it travels through pipes to a holding tank called a bulk tank. The milk comes out of a cow at around 100 degrees Fahrenheit; it is the bulk tank’s job to cool the milk down to about 38 degrees.

Testing milk-

how is milk transported
The milk truck parked at the creamery unloading the milk.

The milk will be stored in this tank until a truck comes and takes it to a processing plant. Every time a milk truck picks up milk from a farm, the driver takes a sample of milk before putting it in with the rest of the milk.

is milk tested, is milk safe,
The Sassy Cow Lab. We test all of the milk that comes into the plant.

Once the milk gets to the plant, a sample from the whole truck is taken and tested. The samples from each individual farm are also tested for quality, butterfat content, protein content, and to make sure there isn’t anything in the milk that shouldn’t be. Farmers are paid a premium if their milk has high butterfat or protein. Likewise, if the test finds something wrong with the milk, like traces of antibiotics are found, the farm will have a big problem. If the truck needs to be dumped, the farm responsible pays for the entire load. You can read more about dumping antibiotic tainted milk HERE. If the milk is safe, it will move to the next step of the process and is unloaded from the truck into another holding tank.

The milk manufacturing process-

Is milk safe, how is milk made
The pasteurizer is a set of pipes to heat up the milk quickly.

The milk will then go through a pasteurizer that heats up the milk to 167 degrees for about 10-15 seconds and then is cooled back down. Pasteurization is used to kill any organisms or pathogens that could be in the milk. While most milk is pasteurized like this, some brands of milk go through UHT Pasteurization. UHT stands for Ultra High Temperature. Milk that is UHT pasteurized is heated to 280 degrees for 2 seconds. UHT pasteurization gives milk a longer shelf life.  

how is milk processed
The separator takes the fat out of the milk and then adds the right amount back in.

After that the milk will go through a separator that separates the butterfat out of the milk. Then depending on what type (skim, 1%, 2% or whole) milk is being bottled, fat is added back in. While many people believe that water is added to milk to change the fat levels, there are very strict rules about what can and can’t be added to milk and water is never allowed to be added. You can read more about that HERE.

Milk has different components-

Butterfat percentage is the percent of the milk that is fat. When the milk is fresh from the cow, on average the butterfat percentage is 3.5%. It can be higher or lower based on the breed of cow (read more HERE). At Sassy Cow, fat that is skimmed from the milk will be put into a cream tank to be used for whipping cream or my favorite, ice cream.

How is milk processed, how is milk made
This is the homogenizer, a pressure chamber, that breaks down the fat globules.

Once the correct amount of fat is in the milk, it will go through a homogenizer. This is a mechanical process that breaks up the fat globules so they are fully suspended in the milk. If milk was not homogenized, there would be a layer of cream on top of the bottle. Homogenizing the milk also extends its shelf life.

Milk has vitamin A and D-

Now vitamin A and D can also be added to the milk. Vitamin D naturally occurs in milk, more is normally added to the milk since humans do not normally get enough in their diet. Vitamin D is important for calcium absorption to have healthy bones. Sometimes Vitamin A is added to milk.
Since Vitamin A is found in the butterfat of milk it’s removed when the fat is taken off in the separator. So it is normally added back in for lower fat or skim milks.

How is milk bottled, how is milk made
Containers are put on to a conveyor belt, filled with milk, capped and rinsed.

Now, it is time to be bottled and stored in the cooler until a truck come to pick it up to take it to the grocery store.

Finally, the milk will be brought to the store and bought by you to be kept in your refrigerator. If you want to know where the milk you buy was bottled, check out

Comments are closed.