Assembly Line

How cheese is made

Cheese is milk split into solid curds and liquid whey, then aged until it develops flavor.

stations
7
things upstream
5
raw sources
3
steps from the ground
2

The short version

Milk, usually pasteurized, is warmed in a vat and seeded with bacteria that turn lactose into lactic acid. Rennet is added and the milk sets into a gel. The gel is cut, heated and drained of whey, then the curd is salted, pressed into molds and ripened for weeks to years.

  1. Warm and seed the milk

    Milk goes into a vat and is brought to a temperature at which starter bacteria thrive. The bacteria eat lactose and make lactic acid, and the starter is chosen for the flavor and texture of the cheese.

    Goes in
    Pasteurized milk

  2. Set it with rennet

    Rennet contains the enzyme chymosin, which snips a protein in the casein micelles. The casein then clumps into a gel, and the milk sets like a soft custard. Many factories use rennet made by fermentation with a fungus.

  3. Cut the curd

    Wire knives slice the gel into small cubes. Smaller cubes release more whey, so they make a drier, harder cheese.

  4. Heat and stir out the whey

    For cheddar the curd is warmed to about 39 °C. The cubes shrink and squeeze out whey. The whey drains away, and the curd is stacked and turned in slabs, the process called cheddaring.

  5. Salt and mill the curd

    Slabs are milled into finger-sized pieces and mixed with salt. Salt draws out more whey and slows spoilage microbes.

    Goes in
    Table salt

  6. Press into molds

    Curd is packed into molds or hoops and pressed so it knits into one solid block or wheel.

  7. Ripen in a cool room

    Cheeses rest at controlled temperature and humidity. Hard cheeses age for months or years, while mold-ripened cheeses like Camembert ripen in weeks because surface mold works quickly.

End of the lineCheese

Worth repeating

  • The first factory for industrial cheese production opened in Switzerland in 1815.
  • In 2022, world cheese production from whole cow milk was 22.6 million tonnes, with the United States making 28%.
  • Before the 1860s mass-produced rennet, cheesemakers relied on bacteria from their surroundings or from the previous batch's whey.

Back to the ground

Follow every input upstream and cheese starts as these 3 raw sources.

Raw milkRock saltSeawater

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Sources

Cite this page: "How cheese is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/cheese

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