More than 23 million jars of Vegemite are produced each year, but Australia's national spread was so unpopular when it launched in 1924 that it was almost scrapped.
The only reason you can still spread it on your toast (with lashings of butter) is due to the determination of its inventor, a chemist named Cyril Callister.
In Vegemite's early days Callister was so determined to promote it as delicious, and nutritious, that he sent a sample to a scientist in Britain who used it treat his sick pigeons.
The birds had something called polyneuritis - damage to their central nervous system - which is similar to beriberi, a disease in humans caused by Vitamin B1 (thiamine) deficiency.
"This was his Eureka moment," said his grandson, Jamie Callister.
In the same way food manufacturers spend millions advertising their product's health benefits today, Callister and his boss, food entrepreneur Fred Walker, started promoting Vegemite as a great source of thiamine.
When a nursing mothers association advocated Vegemite as a good food for babies, the spread's popularity started to grow.
It would finally cement itself as the country's national spread when it was included in the army rations for Australian soldiers in World War II.
The story of Cyril Callister and Vegemite remains relatively unknown, despite the spread's popularity today.
In the latest episode of Science is Golden I interview Cyril's grandson, Jamie Callister, who has spent the past two decades getting to know his grandfather, a man he never met.
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Episode 1: The untold story of Dora Lush
Episode 2: Human guinea pigs
