When Australian chemist Cyril Callister made a food spread out of used brewer’s yeast 101 years ago, he probably didn’t know he was creating such an enigmatic national icon.

Now his grandson Jamie Callister has written a book about the tumultuous history of the product.

He told Millsy and Karl on 6PR Breakfast there’s a lot to dig into when it comes to Vegemite’s history, especially considering how difficult it was to originally get the public on board.

“It rolled off the production line and it was a complete dud, but Fred Walker and my grandfather wouldn’t give up… eventually it got some acceptance,” Mr Callister said.

Press PLAY to hear more history on Australia’s favourite spread

Image: Getty/Brendon Thorne