Introduction: Eggs

Eggs play a very important role in baking. They act as a binder for baked goods, provide moisture, and create steam that is released during baking which acts as a leavening agent. Recipes that call for 'eggs' are referring to Grade A Large chicken eggs unless otherwise noted.

Believe it or not, chicken eggs are complex structures. Let's discuss all of the parts in detail.


Hard Outer Shell

This hard coating is made of calcium carbonate; the same chemical compound that makes up chalk, limestone, and marble. Eggshells are porous so moisture and air can pass through the shell.

Eggshells are coated with a substance called bloom which helps prevent bacteria and dust from entering the egg.

Eggshells are mostly white and shades of brown in color. The color of the shell is an indication of different breeds of chickens and does not affect or determine the quality of an egg.

In fact, a chicken egg shell color is often determined by the earlobe and feather color. There are a few exceptions, but in most cases, if a chicken (hen) has white earlobes and white feathers its eggs will be white. If a chicken (hen) has red earlobes and red feathers the eggs will be a beautiful shade of brown!


Shell Membrane

Inside the eggshell are two very thin, membranes. One that acts as a lining for the eggshell and one that surrounds the albumen, or the white, of the egg. These linings are a second defense against bacteria that may be trying to enter an egg.

There is a small pocket of air between the two membranes, called the air cell, that increases in size as the egg ages. This is most noticeable when eggs are hard boiled — the wide end of a boiled and peeled egg generally has a flat spot which was the air cell.

You can see I am pulling/peeling the membrane out of the eggshell (to show you what it is), however, it does not come out naturally when an egg is cracked.


Albumen

The albumen is the white part of the egg, although it is clear before it is cooked. There is a thin, or runnier, outer white and a thicker inner white that surrounds the egg yolk. The taller the inner white stands, the fresher the egg. It starts to break down and thin as the egg ages. The white of the egg is rich in riboflavin and is about 90% water and 10% protein.

Whites are often separated from yolks in baking. Whites can be whipped or beaten to soft and stiff peaks. Using just the white removes some fat content from a baked good and provides airiness in the finished product.

Common recipes that use only egg whites are; angel food cake, meringues, macarons, and financiers.


Yolk

The egg yolk is the yellow-orange center of an egg. This is what would eventually nourish a chicken if the egg were fertilized and allowed to mature. It is rich in healthy fats, vitamins, and minerals. The yolk is surrounded by a thin membrane that breaks down as an egg ages. Like the inner white, the taller the yolk stands indicates the freshness of an egg.

Egg yolks contain a mixture of emulsifying fats called lecithin. This means that egg yolks can bond to fats and water making it an ideal binder in baked goods.

Yolks typically aren’t used alone without an added whole egg in baked goods, however, they are great for curds or crème anglaise, which can be used as a filling or topping for many delicious baked items!


Germinal Disc

The germinal disc is located on the surface of the yolk. This is a small spot, or indentation that is barely noticeable. If the egg were to be fertilized this is where sperm would enter the yolk.


Chalazae

Pronounced KA-LAY-ZA, these two twisted, cord-like strands of membrane secure the yolk in the center of the egg white and attach to either end of the egg shell. Although it’s not necessary, many people choose to remove the chalazae before cooking or baking.


Blood Spots

I have cracked many, many eggs to find a small blood spot or two in the albumen. This occurs when stress is placed on the egg during development.

If you purchase commercial white eggs you will rarely find a blood spot because the eggs are candled (light held up behind the egg to see if there are any abnormalities). If a blood spot is seen during candling the egg is tossed out. Commercial brown eggs are also candled, however, it's harder to see through a darker colored shell, which allows for more small blood spots to pass inspection.

Small blood spots are generally harmless to eat, although, many people prefer to pick that section out. Do what makes you comfortable. I never pick them out when baking!


How to Crack an Egg

There are a few methods for cracking eggs including; cracking on a flat surface, cracking on the edge of a bowl, or using one hand. None are right or wrong. Below I will cover the different methods, but do what works best for you!

You will always want to try to crack the egg around the wide center where the shell is the weakest. The goal is to not allow any eggshell pieces to get into the egg!

Cracking on a Flat Surface

To crack an egg on a flat surface hold the egg firmly in one hand. Expose the widest (and weakest) part of the egg and hit it hard enough on the countertop to make a large crack. Press each of your thumbs into the dented crack and pull the two halves of egg shell apart. The egg inside will easily fall out...preferably into a bowl! I like to crack eggs near a garbage can so the shells can be easily and cleanly disposed of.

Cracking on the Edge of a Bowl

This method is done exactly as above, however, you hit the egg shell on the edge of a bowl instead of a flat surface. Unless you have a heavy bowl you will need to be holding the bowl securely with one hand while cracking with the other. Otherwise it will just tip over! This method produces a larger/wider crack that's easier to open.

Cracking with One Hand

This is by far the most difficult method but if you can learn to do it, it makes cracking eggs faster and leaves one hand completely mess free! Hold the egg in one hand and hit it on the side of a thin bowl. Hard enough to crack the egg shell almost half way through. With the thumb and pointer finger holding one half of the shell and the three remaining fingers holding the other half of the shell, pry the shell open and free the egg!


How to Separate an Egg

Many recipes call for egg whites only, or egg yolks only, which means they will need to be separated. I will highlight three methods below. The main goal in separating eggs is to not allow the yolk to break. If you are making something like meringue or angel food cake where achieving soft or hard peaks is necessary, small pieces of yolk could be devastating to the finished product.

As an egg comes to room temperature it will relax, so separating a cold egg is easier. If you are new to separating egg whites from yolks use cold eggs!

Separating with Fingers

In my opinion this is the easiest way to separate an egg. Crack an egg into a small bowl and dispose of the shell. With clean hands, gently reach under the yolk and lift it straight up. Let the whites drain through slightly separated fingers. It's that easy! The egg is successfully separated.

Separating with Eggshell

This method is slightly more difficult because the edges of a cracked egg shell are sharp. There is a higher chance of the yolk getting punctured on the shell.

Crack the egg on a flat surface or edge of a bowl. Break the two halves apart and immediately turn both halves (cracked side) up over a bowl. Gently pour the egg from one shell half to the other letting the egg white overflow into the bowl beneath. Repeat until only the yolk is left in the shell.

Separating with a Separator Tool

An egg separating tool has a rounded bottom where the yolk can rest and slats in the sides where egg whites can run through. This method of separating eggs is also extremely easy assuming you actually have the tool! Place the tool on the edge of a small bowl and crack an egg into the separator. Let the egg white run through the slats. If the egg is very fresh the inner white will be thicker and may require some rotating (as seen in the video) of the tool to get the white to flow through the slats. That's it! Easy peasy!


How to Whip Egg Whites

By whipping or beating whites at a fast speed, air bubbles become trapped inside the albumen. These air bubbles will hold and release steam during baking which will give a baked good rise, and result in a light and airy texture.

Lightly Beaten

Many recipes will call for lightly beaten egg whites. This simply means whisking the whites with a wire whisk to break down the inner and outer albumen into a cohesive texture. Eggs are considered lightly beaten when small air bubbles form and the mixture looks somewhat frothy.

Soft Peaks

To properly make soft peaks you will need either; room temperature egg whites and room temperature tools, or tools chilled in the refrigerator and cold eggs. Ultimately, whites and tools should be approximately the same temp.

Plastic bowls have an oily residue that can interfere with properly whipping egg whites and are not recommended. Choose metal, glass, or a ceramic bowl instead.

Using a hand mixer, beat egg whites on low speed until frothy. Turn mixer to high and beat until the bubbles become small and the whites are white in color. You will know when you achieve soft peaks by turning the mixer off and pulling the beaters straight up and out of the whites. The peaks left behind should gently fall over.

Stiff Peaks

Stiff peaks are made the same way as soft peaks; they are just beaten longer. When the beater is lifted straight out of the whites the peaks should stand straight up and retain their small mountain-like peaks without falling over.

Although it is difficult to over whip egg whites, I recommend testing often when whipping to stiff peak stage. If you whip too long the whites will become watery and grainy. They cannot be salvaged or used at this point and will need to be tossed out.


Egg Alternatives

Eggs are among the top food allergens and many people need to avoid them. Luckily there are many egg alternatives!

Chia & Flax Seeds – When chia or flax seeds (whole or ground) are mixed with water they make a sticky, gelatinous egg-like mixture. They are a great substitute for chicken eggs.

One tablespoon of ground chia or flax seeds mixed with three tablespoons of water equals one egg in baking. Just mix together and let stand for 10-15 minutes. Mixture is ready when it becomes thick enough to not run out of the bowl.

This substitute works well in cookies and muffins, but not as well in cake or quick bread recipes. Unfortunately, they cannot be whipped like normal egg whites.

Egg Replacer – Powdered substitutes are also available and may consist of wheat gluten, soy flour, corn syrup, and algae. Directions are usually the same as above. Mix one tablespoon powder with three tablespoons of water for every egg needed. This may work better in baked goods than chia or flax, however, I have never used it. If you have, please comment below on its effectiveness.


Up Next: Lesson 6 — Flours

Get ready to enter the wide world of flours. I will touch on the main types of flours, how they are made, and their role in baking.

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