The product, wherein the iron not became liquid, but comes from a dough -like mass, is called (in translation) source iron (or drawn iron).
You load the oven (bloomer furnace) from the top with alternate layers of charcoal and ‘oer’ (primeval iron). When lit, fill every ten minutes with 6 liters charcoal and 2 liters ‘oer’, which is about 1.5 kiloframs each.

blaasbalgen10 cm above the ground is (preferably heated) air blown in with bellows along two sides. The mass sinks slowly. Near the blow holes, the temperature is 1,350°C, which is lower than the melting point of iron. This iron also takes almost no carbon.
After 12 hours and 100 kilos of charcoal and ‘oer’ the root ball is grown above the blowholes. There can pass no more air through the oven and the process stops. The crumbly lump of iron in the oven will just not be liquid. The (iron) bloom (a sponge of malleable iron and slag) weighs about 30 kilograms.
The Romans call him Lupus (German: Luppé, French: La loupe de fer, Dutch: wolf.)
What became liquefied was sand and clay run out of the furnace as lava (slag).
The newly born bloom is pulled out when it is still hot and gets immediately his first hits.
The trick is to forge out the latter part of this cake of iron and slag particles, and welding iron particles together at once. First in fact you are just knock some hot air out of it. After a dozens of times reheating and beating he begins to look like a bar. Hammering this mass expel impurities and creates gradually wrought iron.

(The Iron Age is situated roughly from -1,200 to +300. Experimental archaeology confirms that there are hundreds of ways to spill this production. In fact, with their possibilities, our ancestors did (following experience with copper,..) an amazing technically high level job.)