Beurre Blanc

Emulsions

When making an emulsification, you’re basically cramming little droplets of oil in between water molecules, making it harder for the water molecules to move around. This creates a thick and creamy consistency, which is found in classical sauces such as hollandaise and mayonnaise.

In his book “On Food and Cooking,” Author Harold McGee refers to an emulsion as “Two Liquids: Continuous and Divided.”

 “The two liquids in an emulsion can be thought of as the container and the contained: one liquid is broken up into separate droplets, and these droplets are contained in and surrounded by the intact mass of the other liquid….The dispersed liquid takes the form of tiny droplets, between a ten-thousandth and a tenth of a millimeter across…The more droplets that are crowded into the continuous phase [read emulsion base], the more they get in the water’s…way, and the more viscous the emulsion is.”

To really make an emulsion work, you need shearing power. In culinary school, the first time we made mayonnaise in our basic skills course our instructor forced us to use a metal mixing bowl and a hand whisk. No doubt this masochistic approach was to teach us how easy us modern cooks have it. The problem with using a hand whisk to make an emulsion is that it has very little shearing power.

With modern day equipment on hand, it is much easier for us to make an emulsion just because we have more shearing power at our disposal. A KitchenAid with a whisk attachment, a food processor, and a good blender all have much more shearing power than a hand powered whisk. Why is this important?

Because the more shearing power you have, the smaller your emulsified “droplets” will be, and the less chance you will have of your emulsification separating (breaking). That’s why, when at all possible, I would recommend using a blender to make your emulsions, or at the very least a food processor. But pure shearing power isn’t enough; to really make a good, stable, emulsion, you need emulsifiers.

Emulsifiers are molecules that allow oil and water to play nicely together. These emulsifiers come in two forms. The first is a string type molecule that at one end likes to bond with fat and at the other end likes to bond with water. A typical example of this is lecithin which is found in soy beans and egg yolks.

The second are large protein molecules that will basically block the oil droplets from getting to one another (aka coalesce). Since they are not able to merge, the oil stays suspended in the water, keeping the emulsion from breaking. The protein molecules found in egg yolks and the casein molecules found in cream and milk are the best protein emulsifiers.

Emulsification also affects the way your palate perceives fatty things. Think of mayonnaise. If you tasted its component parts before they were blended together, you would be just pouring oil on your tongue, and you would wonder what you'd done to deserve this kind of punishment. But once emulsified ... incredibly delicious! The emulsification causes the oil to hit you much more softly, slowly revealing its round, rich flavor rather than drown you in grease.

Lecithin

Lecithin is ideal for making airs, foams, mousses and emulsions. Most commercial lecithin is extracted from soybeans making it both vegetarian and vegan friendly. Lecithin contains both hydrophobic (water-hating) and hydrophilic (water-loving) groups, so it can also be used in making emulsions. Under normal circumstances oil and water do not mix and separate out, creating two distinct layers, but an emulsifier such as lecithin helps to combine these two layers, creating a more stable preparation.

Lecithin is typically derived from soy bean as a by-product of creating soy based vegetable oil. Lecithin is extracted from hulled cooked soy beans by crushing the beans and then mechanically separating out (via extraction, filtration and washing) crude lecithin. The crude lecithin is then either enzymaticaly modified. Lecithin can also be derived from animal sources, such as eggs and animal proteins but animal derived lecithin is more expensive than plant derived lecithin so it’s less common and plant lecithin is more commonly used.

Beurre blanc

Literally translated from French as "white butter"— is a hot emulsified butter sauce made with a reduction of vinegar and/or white wine (traditionally Muscadet) and shallots into which cold, whole butter is blended off the heat to prevent separation. Each piece of butter carries all the ingredients necessary for a new portion of the sauce, so the cook can whisk in one piece of butter, or 100. The small amounts of lecithin and other emulsifiers naturally found in butter are used to form an oil-in-water emulsion. Although similar to hollandaise in concept, it is not considered either a classic leading or compound sauce. This sauce originates in Loire Valley cuisine.

Beurre blanc will begin to separate and leak butterfat if it’s temperature rises above approximately 135 degrees. Most damaging to the beurre blanc is letting it cool to below body temperature. The butterfat solidifies and forms crystals around 85 degrees, and the crystals poke through the membrane of emulsifiers and fuse with each other, forming a continuous network of fat that separates when the sauce is reheated. Ideally the sauce should be kept at 125 degrees.

Preparation

A good beurre blanc is rich and buttery, with a neutral flavor that responds well to other seasonings and flavorings, thereby lending itself to the addition of herbs and spices. It should be light and airy yet still liquid, while thick enough to cling to food. Beurre blanc is prepared by reducing wine, shallots, and herbs, if used, until it is nearly dry. Although not necessary, cream can be added at this point to act as a stabilizer to the sauce. Lemon juice is sometimes used in place of vinegar and stock can be added as well. Cold, one-inch cubes of butter are then gradually incorporated into the sauce as the butter melts and the mixture is whisked. The sauce can separate by either over heating or cooling. If it heats past 136°F, some of the emulsifying proteins will begin to break down and release the butterfat they hold in emulsion. If the sauce cools below 80°F, the butterfat will solidify.