bloomery furnace

The bloomery process is an ancient method of iron smelting. It involves heating iron ore with charcoal in a furnace. Because early furnaces couldn't reach iron's melting point, the result was a spongy mass called a bloom, intermingled with slag. This bloom was then reheated and hammered to remove slag and create wrought iron.1

Later advancements included low-shaft furnaces powered by water to drive bellows, producing larger blooms. High bloomery furnaces evolved into the Stuckofen, which yielded very large blooms. These bloomeries were crucial for iron production until the 15th century, when the blast furnace began to emerge.12