So I take a sip and try to absorb the taste. The symphony of flavours certainly does seem more vivid – as if the conductor has suddenly turned up the orchestra’s volume. I’m also conscious of the way I can pick apart the different notes – the smoke, the rustle of silk across the tongue. It is indeed a “hard problem” when I consider how the brain constructs those many distinct “qualia” – instances of subjective experience which words can never express fully – and builds our conscious experience.

As I ponder that thought, Berman explains how his research has informed his understanding of the drink. All varieties of coffee will share a common note that comes from just one oil – caffeol. “It makes up a small portion of the bean – just 0.5%,” he tells me – yet without it, the drink would not be recognisable as coffee. In contrast, he says, there is no single “essence of tea”; tea is made from a wide variety of compounds, but no single one is essential.

Tea-ism versus coffee-ism

Berman proposes that coffee and tea therefore illustrate two different philosophical outlooks. Tea is about the way many different flavour components complement each other, he says – recalling the Eastern concept that all beings are interconnected. Coffee, by contrast, is defined by that single key ingredient caffeol, which stands apart from the other flavours – perhaps an apt metaphor for a Western tendency to draw boundaries between the body and spirit, say. I have a feeling he might not persuade everyone.

Coffee's single ingredient, however, can be deceiving. Taking a sip, I feel as though the distinctive caffeol flavour is firing up my tongue – yet this is an illusion. To explain why, Berman tells me to hold my nose as I take another sip. All I am left with is a faint ghost of the original flavour. “That’s one of the surprises in it,” he says. “You think you are tasting coffee – but if you engage in introspection, you realise it’s actually a smell that is misperceived as a taste.”