Due to their different densities, oil and water want to stay separated, but sometimes they put aside their differences and play nicely together!
You can find evidence of this in your kitchen- salad dressings, mayonnaise, butter, milk- all mixtures of oil and water known as emulsions. Let’s find out more from someone who knows his way around a kitchen, Chef Thad Stuckey.
You can try this for yourself by taking oil and water in a jar and shaking it. It won’t evenly mix like sugar or salt in water but will mix with small oil droplets hovering in the water… for a moment. This simple mixture barely lasts 5 minutes before separating, so how do emulsions like mayonnaise stay stable in your pantry? As it turns out, agitation is half of the process. The other half is much more important- emulsifiers.
An Egg-cellent Solution
Emulsifiers are the chemicals that make emulsions happen. The most widely used emulsifier comes from something that’s likely in your fridge right now.
“Eggs make a great emulsifier because they have this chemical compound called lecithin. So lecithin helps hold that emulsion together better than any other product out there, ” says Stuckey.
So let’s try that! Adding an egg yolk, where that lecithin lives, to our previous mixture that didn’t hold up. Notice how it doesn’t separate!
Lecithin and other emulsifiers do this well because of their chemical structure- one side loves oil while the other loves water- keeping both in a stable mixture! This is why mayonnaise, hollandaise, salad dressings use egg in them!
The eggs do the work on a molecular level, but it’s up to the chef to force that oil and water together by whisking…a lot. Thankfully there is a shortcut by using a food processer or blender.
From egg-based emulsions in your kitchen to other natural and synthetic emulsions in cosmetics and skincare- you probably use mixtures of oil and water daily.
Storm Team 2 Meteorologist David Dickson