Ready to conquer the culinary challenge of emulsifying two liquids that normally hate each other? Maybe you’re trying to add oil to a vinaigrette dressing, combine cream and stock for a luxurious soup, or even make mayonnaise with oil and egg yolks. Maybe it didn’t work. Maybe it was a disaster. I’ve been there too.
Learning how to emulsify two ingredients is a SUPER BASIC culinary skill (really… this is a first semester skill taught in every culinary school in America!). But it DOES require a bit of background knowledge to really understand and get right every time. If you want to make good food, you’ve got to learn how to do this… so let’s get to it!
What is an Emulsion?
An emulsion is a combination of two liquids that are typically immiscible ( a fancy way of saying they hate each other and will separate as soon as possible, such as oil and vinegar). In food products, it refers to a combination of fat and water molecules held together by a special ingredient called an emulsifier. Many common foods are emulsions, including mayonnaise, salad dressing, maple syrup, and even ice cream. The technique creates smooth mixtures, often used in baking and cooking. Emulsions are popular for making rich sauces that wouldn’t be possible with just two ingredients; the fats give flavor, while the waters provide volume and texture.
Because they come from natural ingredients, these food emulsions are usually healthier than premade or premixed products made from nasty chemicals, laboratory flavors, and powdered happiness.
So what are emulsions anyway?
Emulsions are a suspension of one liquid in another, such as oil and water, stabilized by an emulsifier like lecithin. An emulsifier is any microscopic particle that plays well with both oil and water – each particle has one hydrophobic”tail” which attach to the bits of oil, and a hydrophilic “head” facing out. The end result is a super-tiny sleeping bag protecting the oil droplets from the water.
Food emulsions come in many forms, from milk and dressings to chocolate, sausages, and ice cream. The two most common types are oil-in-water (O/W) and water-in-oil (W/O).
O/W emulsions are more common because they’re easier to make. These emulsions are often oils with vinegar or juice kept in suspension – like a salad dressing. W/O emulsions, such as butter or margarine, use smaller droplets of water suspended in oil. The flavor and texture of food emulsions vary depending on their ingredients and the emulsifier used. So while they are all essentially composed of the same elements – fat, water, and an emulsifying agent – these ingredients can combine to create entirely different flavors and textures.
BASIC TERMS
- Emulsion – THE RESULT – a stable mixture of two or more things which do not normally mix (are immiscible) – in the culinary world, we’re talking about fat and water;
- Emulsify – THE PROCESS – the act of creating a temporary or permanent emulsion from two things which normally don’t mix
- Emulsifier – THE CATALYST – also known as “stabilizers”
- Two Types of Emulsions with Examples
- Water in fat W/O (butter [15%], vinaigrette [25%], hot dogs)
- Fat in water O/W (milk, ice cream, espresso, ganache, chocolate)
- Breaking – when an emulsion separates – the water or fat pools due to being added too quickly, with time, or with too much heat (curdling)
OTHER EMULSION TERMS YOU SHOULD KNOW
- Immiscible – not mixable or blendable
- Suspension – the permanent or semi-permanent combination of fat and water; a uniform, homogenous solution – mayonnaise is a suspension
- Colloidal Suspension – a temporary emulsion created through limited shearing force (agitation); the oil, broken into smaller bits via brute force, is suspended briefly in water. Once the force is over, they separate once more – most vinaigrettes are colloidal suspensions… temporary emulsions
- Hydrophilic – loves water
- Hydrophobic – hates water
- Shearing Force – physical agitation (through shaking, whisking, stick blender, food processor)
EMULSIFIERS USED IN SALAD DRESSINGS
- Lecithin – the natural emulsifier found in egg yolks; a fatty substance that is soluble in both fat and water, will readily combine with both the egg yolk and the oil or butter, essentially holding the two liquids together permanently
- Mucilage – the mix of proteins and polysaccharides that surrounds the mustard seed hull and is highly effective at stabilizing emulsions
- Garlic and honey – traditionally used to thicken and flavor; limited emulsification properties; garlic must be a paste; honey must be vigorously agitated
- Soy lecithin powder– vegetable-derived emulsifier similar to the lecithin found in egg yolk
- Xanthan gum – Xanthan Gum is a plant-based thickening and stabilizing agent made from a bacteria, Xanthomonas campestris; it works as an emulsifier, encouraging liquids that normally don’t like one another to mix together. Second, it works as thickener, increasing the viscosity of liquids and batters. Third, it can create a creamy texture.
TYPES OF EMULSIONS
- Temporary – will separate after a few hours and need to be re-agitated before using – basic vinaigrette;
- Semi-Permanent – will separate as they cool – butter sauces (Hollandaise and Pan Sauces)
- Permanent – remain thickened for an extended period of time – thickened with emulsifier (mayonnaise)