The curing salts that are applied to the pork belly affect flavour too, in part by changing the course of the chemical reactions the fats can take. They arrest progress down certain routes and shunt the bulk of the molecules down others.

When the cured pork bellies are smoked, they take on another set of flavour compounds. The smouldering wood releases acrid-smelling phenols as well as sweeter-smelling compounds, including the evocatively named maple lactone. “It's the combination of those two – the acrid and the sweet – that creates the real flavour of smoke,” Crosby says. “You really don't have the flavour of smoke without both of those.”

Fake bacons

The last major contributor to bacon's goodness is the Maillard Reaction, which occurs when sugars and amino acids combine under high heat and which you induce whenever you toast bread or sear meat. Crosby says the molecules generated at this phase include more furans, as well as pyrazines and thiazoles, which have nutty, caramelised tastes and aromas. As it happens, chocolate also owes some of its flavour to the Maillard Reaction, thanks to the browning of the cocoa beans. But it's not clear if this shared chemistry has anything in particular to do with why bacon chocolate bars are so delicious – the science of flavour pairings is thorny and controversial.