Did you know that bananas naturally contain a substance that is also used for testing gas masks?

Called isoamyl acetate, it’s one of a class of chemicals called esters1 that are strongly aromatic and are responsible for many of the smells and flavours we distinctively associate with certain foods. It’s naturally found in bananas, and also in pears, tomatoes and even coffee.

Bananas: it’s complicated

I’m interested in isoamyl acetate because I don’t like bananas, but I do like a lot of “banana flavoured” things - like banana ice cream, or banana liqueur. This never made much sense to me until I learned that most “banana flavour” is designed to emulate a different variety of banana than what you can buy in a store today!

99% of global banana exports today are of a variety known as the Cavendish banana. However, before {TODO check date} another variety - called Gros Michel or “Big Mike” - was the widespread one. Compared to Cavendish (modern) bananas, Gros Michel bananas are sweeter, firmer, and have a higher concentration of - you guessed it - isoamyl acetate. They’re more banana than (modern) bananas.

TODO reason for Gros Michel disappearance

In other words, any “banana flavoured” product developed before {TODO year} was actually meant to taste like a Gros Michel banana. And the recipe was likely not updated after the actual banana crop switched varieties worldwide. In particular, “banana candy” is often flavoured with synthetic isoamyl acetate rather than natural banana, making it even closer to the Gros Michel.

I find this fascinating. This is a kind of olfactory time travel - I’ve developed a preference for a fruit I could never have naturally tasted, without being born decades earlier.2

Banana flavour without bananas

As noted above, isoamyl acetate can be synthesised in a lab. This makes it easy to produce “banana candy” without any banana ever being involved. The ester is also produced naturally during some types of fermentation, producing the banana flavour notes in some beers and spirits.


  • Alcohol - fermentation
  • Brussels sprouts
  • Other isoamyl acetate facts - bees! Gas masks
  • Cavendish - 99% of global exports but only 47% of global consumption.


  1. Note for anyone who actually knows organic chemistry or food science: I’m no expert in this topic, and this is not novel information - more of a report of an interesting Wikipedia hole I fell down.

  2. Another example of this phenomenon is heirloom tomatoes - which is what tomatoes used to look and taste like, before supermarket economics saw them almost universally replaced by a largely tasteless variant that is bright red, smooth, round, and firm-skinned to survive long truck journeys.

    In the reverse direction, many people’s childhood dislike of Brussels sprouts wasn’t (only) because of juvenile palates or poor cooking, but because they actually tasted bitter - until the 90s, when a new variety became widely popular that was engineered to reduce bitterness.