Spilanthol

Last September I took my first trip to Rio de Janeiro in Brazil. A food tour gave me the opportunity to taste a wide range of local cuisine. The tour’s penultimate eatery was an Amazonia restaurant where we had a traditional north Brazilian soup called tacacá. It was a cassava broth with these extremely salty dried shrimps and a funny green leafy veg that looked just like watercress. Munching on the bitter green stuff set off this unusual tingling and numbing sensation across my mouth followed by a rush of saliva. It wasn’t for me.

On the way to our final eatery, we paused for a shot of cachaça – Brazil’s national spirit – a liquor distilled from fermented sugar cane. Only this was a special cachaça, flavoured with that green stuff from the soup. ‘Before drinking it,’ our guide said, ‘dip your finger in the glass and rub the liquid around your lips.’ Eugh! There was that numbing feeling again.

Acmella oleracea is the proper name for the leafy green plant flavouring the soup and the shot. It’s an annual herb grown in tropical and sub-tropical regions with pompom-shaped red and yellow flower heads. It goes by a variety of names including Jambu, the toothache plant, paracress and electric daisies. And the compound behind the unusual effects I described is called spilanthol.