Without charcoal, there would have been no Iron Age. No Bronze Age, either. In fact, no manufacturing at all to speak of. For until the mass extraction of oil and coal, charcoal was the best fuel available: comparatively smokeless, light enough to transport easily, and crucially, capable of generating enough heat to smelt metals. Without charcoal we might still have had civilizations, but they would have been very different. Less warlike, for starters, given that it was a prerequisite for fabricating weapons, and also a key ingredient in gunpowder, first manufactured in China during the T’ang Dynasty.

The process of making charcoal begins by stacking logs neatly into a pile (known as a “clamp” in Britain) which is covered with earth or sod, or else placing the wood into a specialized kiln built of stone or brick. The material is then burnt slowly – it takes days, rather than hours – releasing moisture and gases. This creates two products. One of them, especially plentiful when pine is burnt, is tar, a sticky black residue useful for sealing ship hulls, improving the grip on baseball bats, and waterproofing clothing. (British sailors were nicknamed “Jack Tars” because they wore such garments; this is also the origin of the term tarpaulin, often abbreviated to tarp.) The other product of the controlled burn is charcoal: a dehydrated, nearly pure form of carbon.

In early nineteenth-century Italy, nothing was more daring than to be a charcoal burner. These carbonari weren’t your average forest-dwelling fuel producers (we’ll get to them in a moment), but a secret society dedicated to the establishment of a constitutional monarchy. No one is quite sure how radicalism and charcoal came to be associated in this way. One popular theory is that the Italians were inspired by earlier Scottish insurrectionists, who blended in among rural charcoal manufacturers in order to evade surveillance. It was an ideal guise. The craft is usually undertaken well away from cities, both to minimize fire risk and for ease of access to woodlands.

The name carbonari, then, had quite a lot of material intelligence in it. It suggested a position in society that was marginalized yet vitally necessary, with an added implication of explosive potential. The association with poor artisan communities – charcoal burning has never been a particularly lucrative trade – may also have helped them to recruit from the lower classes. When carbonari were among trusted friends, they might sport a twig of charcoal tied with a ribbon to indicate their allegiance. The metaphor was further extended in their closed-door meetings, in which a revolutionary unit (known as a vendita, for the rural markets where charcoal is sold) would convene in a “hut” furnished with actual tree stumps. In place of a gavel, meetings were chaired with hatchet in hand.

Just at this time, ironically, actual charcoal burners were just starting their long road to obsolescence. This was a very gradual process. As late as 1933, in the depths of the Depression, a writer for the New York Sun noted that although inhabitants of the metropolis were little aware of it, they were still dependent on charcoal makers who made fuel for factories and restaurants: “following certain by-roads in Connecticut, Massachusetts or in fact any of the New England States, there will occasionally come into view near the edge of the woods groups of mounds which tell their own story.”  During the gasoline shortages of the 1930s, there were even some cars run on charcoal in Japan and Europe – a phenomenon that has also been reported recently in North Korea.

Maybe charcoal will enjoy a wider revival as we pass peak oil and contend with whatever energy crises lay on the far side.  As long as the fossil fuels are flowing, though, it simply can’t compete, as it contains much less energy and produces even more polluting emissions. As a result, this once-crucial material has been relegated to purposes that are all but economically irrelevant – yet oh-so-pleasure-giving. One of these, of course, is outdoor grilling, a practice that vastly predates backyards (people were already cooking over charcoal in Paleolithic times), but does have a surprising connection to modern industry. Kingsford, the dominant brand in the USA today, began as a subsidiary of the Ford Motor Company, in 1919. There was a great deal of hardwood in the Model T – it was used in the frames, running boards, and joining blocks – and that also meant a great deal of wood waste. Transforming the offcuts into pillow-shaped briquettes, incorporating pulverized limestone for stability and corn starch as a binder, was an easy way to generate more value.

The problem, initially, was that there was very little demand to meet this huge supply, but Ford soon hit upon the idea of promoting barbecuing as a family pastime. Initially, their advertisements emphasized cooking out in nature, “away from the paved highways, deep in the hidden solitudes.” (The resemblance to the rhetoric of the carbonari was presumably unintentional.) After World War II, the growth of suburbia – and arguably, a deep-seated need to assert masculinity that continues unabated to this day – motivated the invention of that reassuringly patriarchal figure, the apron-wearing BBQ Dad.

Charcoal’s use as an artistic medium also goes way, way back. In fact, it is with this material that the very earliest human artworks were made (often in combination with red and yellow ochers). It is easy to imagine why this would be: when early humans first thought to make images on rock walls, the remnants of their cooking fires were sitting right there. They had discovered a medium of extraordinary subtlety, capable of making a decisive mark but also smoky, soft contours. The famous horses in the caves at Lascaux, which so powerfully express a sense of forward motion, are drawn with charcoal. So is the menagerie of the Ardèche gorge, memorably captured by Werner Herzog in his 2010 film The Cave of Forgotten Dreams, and beautifully described by the art critic John Berger: “As I draw, I ask myself whether my hand, obeying the visible rhythm of the reindeer's dance, may not be dancing with the hand that first drew them. It is still possible here to come upon a crumb of broken charcoal that fell to the floor when a line was being traced.”