Study says chemical reactions are answer to toast’s appealing smell

The study says chemical reactions caused when bread is toasted create caramel and strawberry aromas (Photo: René Ehrhardt)

Scientists believe they have uncovered the chemical code behind why the smell of toast in the morning is so appealing.

Existing research has already shown that smell is the strongest sensory memory trigger for people, with people favouring smells that remind them of pleasant childhood memories.

The smell of toast has topped a number of favourite smell surveys in the UK; something which researchers at Cardiff University believe is down to the chemical make-up of one of our favourite breakfast foods.

Reactions that take place when bread is toasted cause scents similar to caramel and strawberries to be released:

The laboratory tests conducted found four main odours – the chemical names are followed by their commonly ascribed aromas:

  • 2-acetyl-1,4,5,6-tetrahydropyridine (caramel)
  • 2-furfuryl methyl disulphide (roasted coffee, sulphurous cooked meat and liver, onion and garlic nuances)
  • 2-acetylpyridine (corn-like with a musty nutty nuance )
  • 2-furfural (almonds)

This closely mirrors another historical study, conducted by Rychlik and Grosch (1996) which found two additional odours, as being the predominant contributors to toasted bread smell:

  • 2-acetyl-1-pyrroline (roasty, nutty, ham, sweet)
  • 4-hydroxy-2, 5-dimethyl (2H)-furanone (strawberry-like/caramel)

The study speculates that these added ‘good smells’ combined with the use of toast as a ‘comforter’ for many people have contributed to the scents popularity and its success as a sensory memory trigger.

The study adds that with around 80% of the UK population regularly eating toast for breakfast at one point during the week, the scents familiarity allows it to be more intrinsically linked with memories than other smells:

“Because of the unique frequency and universality of exposure, toast, and the odour of toast, has a greater capacity than perhaps any other odour to evoke early childhood memories and these memories will, for the most part, be happy, comforting and pleasant memories.” explains Professor Tim Jacobs, author of the study.

“It is entirely conceivable that we can sniff our way back to happy childhoods with the aroma of toast.”

Perhaps ironically the School of Biosciences 24-page study, which also examined the UK’s attitudes to toast, found that while the aroma was associated with happy childhood and holiday memories in most places in the UK – the lowest pro-toast results came from the study’s base in Cardiff.