Ever find yourself wondering why you’re willing to shell out for an expensive (albeit delicious) bowl of romaine lettuce and croutons?
A classic Caesar is one of the simplest salads out there: it’s effectively just a mix of romaine lettuce, parmesan cheese, and croutons. But sometimes the most basic dishes require the most technique.
Allow me to let you in on a little secret: a Caesar salad recipe is only as good as its dressing.
Indeed, nailing the dish—one that tastes just as good as your go-to order at your favorite restaurant—is all about prepping the perfect homemade Caesar dressing. The creamy, tangy, umami-rich sauce is the ideal complement to the crisp lettuce and crunchy croutons. When done well, it’s divine. When done poorly, it ruins everything—whether or not the salad options in the airport kiosk looked less gnarly today. (I’m actually shuddering as I think about those gloppy bottled dressings with artificial anchovies).
In today’s episode of Something to Chew On, I’ll be making a simple Caesar salad recipe. And more importantly, I’ll be walking you through everything you need to know about the science of perfecting dressing from scratch.
The secret to any delicious dressing—in addition to using quality ingredients—lies in the art of making an emulsion. What is an emulsion, exactly? As a basic definition, an emulsion is a mixture of two liquids that wouldn’t normally mix together, like oil and water.
There are three types of emulsions:
Temporary, like a basic vinaigrette that you have to shake up every time you drizzle it.
Semi-permanent, like hollandaise sauce.
Permanent, like mayonnaise or chocolate. (The latter is an emulsified mixture of cocoa butter and milk.)
In order to make an emulsion you need to add something that serves as an emulsifying agent. Simply stated, this is an ingredient that helps your two liquids come together and stay together—either temporarily or permanently—when the mixture is agitated. An emulsifying agent is like a mutual friend that holds an oil-based liquid in one hand and a water-based liquid in the other; it creates a chemical bond with each one and then serves as a bridge between the two.
The most common emulsifier is egg yolk, a key ingredient in mayonnaise (which is one of the emulsifying agents we’ll be using in our dressing recipe). Egg yolks contain a protein called lecithin which binds the oil and yolks in mayo together. Butter and mustard are two other types of emulsifying agents.
A stable emulsion means the droplets of one liquid become evenly dispersed within another, which makes the resulting liquid noticeably thicker than the two liquids you started out with (just think about the semisolid texture of mayo). In the case of our salad dressing, oil droplets are suspended within lemon juice, Worcestershire sauce, mustard, etc. Here, mayo and dijon mustard both act as emulsifiers. This is a temporary emulsion which is formed by whisking the ingredients together until well-blended.
So why do we need an emulsion to make our Caesar salad taste good?
Because lettuce leaves have a thin, waxy, water-resistant protective layer on their surface. This matters because water-based liquids like vinegar or lemon juice run right off the leaves, and oils tend to cling to them and cause them to soften and wilt. We need some sort of Goldilocks-level middle ground.
Enter: an emulsified mixture of the two types of ingredients. This is the best way to ensure that your lettuce greens keep their crisp texture, because in this state the vinegar will surround droplets of oil, keeping them trapped and preventing contact with the lettuce.
Taste and texture-wise, we’ll call that just right.