They are not interested in trees used as fuel. The bad news is that while ancient sources are often very interested in trees (entire books about them, in fact), they are generally interested in trees used to make things like ships, buildings, furniture and weapons essentially, elite products. But we are also told that chestnut and fir also work well, and we see a fair bit of birch in the archaeological record. Pinewood seems to have been a consistent preference, both Pliny ( NH 33.30) and Theophrastus ( HP 5.9.1-3) note it as the easiest to use and Buckwald ( op cit.) notes its use in medieval Scandinavia as well. The good news is we needn’t be too picky about what trees we use ancient writers go on at length about the very specific best woods for ships, spears, shields, or pikes (fir, cornel, poplar or willow, and ash respectively, for the curious), but are far less picky about fuel-woods. Indeed, a staggering number of trees, if iron production is to be done on a major scale. But apart from that, by and large the fuel to create all of the heat we’re going to need is going to come from trees.Īnd, as we’ll see, really quite a lot of trees. In China, development was more rapid and there is evidence that iron-working was being done with coke as early as the eleventh century. Prior to that, it seems that the use of coal in iron-production in Europe was minimal (though coal might be used as a fuel for other things like cooking and home heating). We have records of early experiments with methods of coking coal in Europe beginning in the late 1500s, but the first truly successful effort was that of Abraham Darby in 1709. Indeed, the reason we know that the Romans in Britain experimented with using local coal this way is that analysis of iron produced at Wilderspool, Cheshire during the Roman period revealed the presence of sulfur in the metal which was likely from the coal on the site. Without that conversion, the coal itself both does not burn hot enough, but also is apt to contain lots of sulfur, which will ruin the metal being made with it, as the iron will absorb the sulfur and produce an inferior alloy (sulfur makes the metal brittle, causing it to break rather than bend, and makes it harder to weld too). The problem with coal is that it has to go through a process of coking in order to create a pure mass of carbon (called ‘coke’) which is suitable for use. Instead, the fuel I gather most people assume was used (to the point that it is what many video-game crafting systems set for) was coal. Peat seems to have similar problems, although my understanding is it can be reduced to charcoal like wood I haven’t seen any clear evidence this was often done, although one assumes it must have been tried. Manure, used as cooking and heating fuel in many areas of the world where trees were scarce, doesn’t – to my understanding – reach sufficient temperatures for use in iron-working. Now it is absolutely true that there are other common fuels which were probably frequently experimented with and sometimes used, but don’t seem to have been used widely. The thing is, all of that energy has to come from somewhere and that somewhere is, by and large, wood.

The reader may be pardoned for having gotten to this point expecting to begin with exciting furnaces, bellowing roaring flames and melting all and sundry. And if you want updates whenever a new post appears, you can click below for email updates or follow me on twitter for updates as to new posts as well as my occasional ancient history, foreign policy or military history musings.īut let’s start with the single largest input for our entire process, measured in either mass or volume – quite literally the largest input resource by an order of magnitude. Warning: Many, many trees were harmed in the making of this iron.Īs always, if you like what you are reading here, please share it if you really like it, you can support me on Patreon. As we’ll see, we are going to do this by applying heat and (more importantly) chemistry: Note that this week is going to be spent just getting our iron ore into being an iron bloom, the first two steps. This week, we’re going to make our way from just rocks to an actual mass of metal rather than just some metal-bearing ore. Last week we prospected our iron ore and extracted it from the ground and did some initial mechanical processing (washing, sorting, crushing). This week we continue our four-part ( I, II, III, IVa, IVb, addendum) look at pre-modern iron and steel production.

Unyielding crude iron armor