Food for thought: Why do egg-whites foam when you whisk them?

Roy Ballam
Sunday 17 January 1999 00:02 GMT
Comments

Your support helps us to tell the story

This election is still a dead heat, according to most polls. In a fight with such wafer-thin margins, we need reporters on the ground talking to the people Trump and Harris are courting. Your support allows us to keep sending journalists to the story.

The Independent is trusted by 27 million Americans from across the entire political spectrum every month. Unlike many other quality news outlets, we choose not to lock you out of our reporting and analysis with paywalls. But quality journalism must still be paid for.

Help us keep bring these critical stories to light. Your support makes all the difference.

THE METAMORPHOSIS of globular egg-white to fluffy peaks of foam is one of the many culinary facts we take for granted. But how does it work?

As liquid egg-white is whisked, the mechanical action causes its proteins to unfold and form a network, trapping air in tiny pockets. As the whisking continues, the air pockets become smaller. The change in colour (from translucent to brilliant white) is due to a trick of the light with the bubbles, rather than the egg's pigment. Essentially, the foam is composed of small gas bubbles dispersed through the egg-white. If the foam is left to stand, it will eventually collapse back into a liquid. But the physical change caused by whisking denatures the protein, depriving it of elasticity - it cannot be re-whisked successfully. If the foam is baked, protein coagulates and moisture is driven off, forming a solid foam commonly known as meringue. Roy Ballam, British Nutrition Foundation

Join our commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in