The Amish do often boil their milk at home for preservation like when making powdered milk or for safety.
Although some Amish prefer to not boil the milk and drink the milk raw.
Most Amish people and Amish communities prefer to drink raw milk and avoid any commercial pasteurization or boiling as the Amish mostly view pasteurization and boiling of the milk to be unnatural.
The Amish have varying practices when it comes to their milk and health considerations as well.
Some Amish dairies do pasteurize their milk, though using commercial pasteurization methods like High Temperature Short Time for wider sale.
Many Amish people believe that raw milk retains enzymes and bacteria that is beneficial to health, which makes raw milk healthier and easier to digest than milk that has been pasteurized, which when pasteurized the Amish see the pasteurized milk as dead.
Amish most often also maintain small farms and produce milk for their communities and prefer to keep their milk and dairy in it's natural and unhomogenized state.
When Amish do boil their milk the Amish use heat, which is sometimes from wood fires to dry the milk into powder for long term storage, which is a common method of preserving the milk without refrigeration.
And some Amish people may boil the raw milk at home as a makeshift way of killing any bacteria, although boiling the raw milk even at home is not the Amish peoples standard practice for drinking the milk.
And some Amish owned dairies use modern HTST pasteurization to sell milk to the broader markets, but they often leave the milk non homogenized.