Because we import much of our charcoal from South America via trucks and ships, distillation has to stop at about eighty percent to give the wood enough rigidity for transportation. ‘The trouble is, when it gets to its final destination, that charcoal still has to go through the final distillation process, which will only happen in the grill,’ says Mark. ‘Any lingering elements that are burnt off will stick to anything in its way, so food will pick it up.’

Not a problem, then, for local charcoal makers like Mark. ‘Because we don’t have that, we can get a really clean coal so when it cooks it’s in its most pure state.’

‘Clean’ as it may be, Mark leaves a bit of character in every species of wood, each yielding its own unique flavour. The difference in the clarity of note, he says, is like the distinction between sparkling wine and Champagne.

‘We have a strong view that each wood carries an identity because of its soil type and where it grows. For instance the Weald of Kent, where everything’s washed out of the downland, produces a certain environment that’s similar to the land in Champagne in Reims – if you took away The Channel, it’s the same thread of earth that goes underneath it.’

This thread of earth has a clay base that’s quite claggy and full of stone. What that means, as Mark says, is that you have conditions that produce a plant high in integrity. ‘It’s a harshness of climate which produces a certain type of plant, a certain type of fruit and a certain type of wine.’

And that same harshness is true of the Weald. ‘The wood that grows in that part of the downland is much slower growing than other places because the land is much harsher, but what it does to the flavour is it makes the grain tighter and the woody notes more intense.’

One species that’s become relatively ubiquitous in the Weald – due to the way it thrives – is silver birch. It’s a good growing harvest plantation crop, meaning it plants itself and regenerates easily once it’s harvested. There are two virtues to this. One is that it ensures Mark and his crew aren’t stepping heavily on the forest. The other is the ability to keep restaurants well supplied with an essential ingredient that provides zesty, citric notes to their cooking.

‘Birch sap is high in natural sugar,’ says Mark. ‘When we have that in our blend of coal, say in a Josper oven, those aromatics become part of the environment the food cooks in. It’s a very nuanced and subtle thing, and it’s like the perfect climate.’

This idea of trees possessing a sense of terroir becomes easier to understand when you look at what cider makers have been doing for the past 2,000 years or more. ‘You have two main areas for growing cider apples – Suffolk and Somerset,’ says Mark. ‘Somerset has quite a harsh soil type that produces the fruit note, whereas in Suffolk they’ve got ancient glacial flood plains, with dark sediment and clay soil, which result in a balance within the fruit.’

As you can probably tell, Mark’s been in the log business a while – since his teens, in fact, when he worked as a tree surgeon. He spent many of his former years around wood, including a spell living in the Ardennes in Belgium. Despite all this time around places where fire, wood, and food combine, and the twelve years he’s had London Log Co running, it’s only within the past five years that he’s been supplying the restaurant industry. But with all this knowledge of wood, it’s worth nothing that Mark’s principles aren’t just about trade.

‘When we work with people like Tom Adams [of Pitt Cue], we have a dialogue about what they’re trying to create. We work with The Fat Duck when they’re doing development – they talk to us about what the dish is going to be and what they’re looking for and we’ll find a note that will complement that and make it happen. The relationships are quite nuanced in that we’ll say look, there’s a methodical way of running these grills, and it can be up to you what you put in or take out.’

While home cooks might not have quite the same access to Mark’s council, London Log Company’s Deptford woodyard is open to visits from life-fire enthusiasts. ‘Or,’ says Mark, ‘if they’re at the other end of the country, we’re quite happy to point them to a company who’ll mail order. It’s not only Log Co who supply charcoal.’

As summer slowly unfolds, it could, with any luck, be a busy season for discerning live fire cooks, whether at home or in a restaurant kitchen. With the wealth of barbecue and grill joints in London, not to mention Meatopia on the horizon, the same can certainly be said of Mark. But, having got to know him, I’m not sure he’d have it any other way. ‘People like Tom Adams and restaurants like Hawksmoor have grown their profile on elemental cooking,’ he says. ‘Being a part of that is a really interesting journey.’