What could possibly be involved in simply hard-cooking a couple of innocent eggs?
Well, should they be started in tap water or boiling water? How long should they cook? How can you prevent that yucky green on the surface of the yolk? How can you cook them so that they will peel smoothly and not leave you with pitiful, pitted whites? How can you get the yolk in the center and not off to one side?
Oh, dear! There's more to this simple egg than meets the eye.
Egg experts use the term hard-cook instead of hard-boil to indicate that eggs should not be boiled. They are brought to a boil, but then the heat is turned down or off so that they will be tender and not rubbery. The secret of tenderness is gentle cooking.
There are two schools of thought about how to prepare hard-cooked eggs. In the boiling-water start, the eggs are gently lowered into boiling water, then heat is turned down to a low simmer. The eggs must be at room temperature or warm for the boiling start. An egg straight from the refrigerator will crack when it hits boiling water.
The other way is the cold-water start.
Hard-cooked eggs can be cooked gently with either technique.. I prefer a cold-water start because I don't always have time to warm the eggs before cooking.
The American Egg Board's recommended procedure for hard-cooked eggs is to start them in regular tap water (they can come straight from the refrigerator), cover them by at least an inch with tap water and set them on medium heat. Cover and bring to a full boil. Turn off the heat and let stand 15 minutes.
Pour off the hot water and rinse with cold running water for five minutes. Pour off the water, shake the pan vigorously to bang the cooked eggs against each other and the sides of the pan. Shells will crack all over. The eggs are then easy to peel under running water. Some people prefer to roll each egg on the counter to crack it all over. Because it saves time, I find the shaking method wonderful, especially if you're cooking a large number of eggs.
Older eggs (one week to 10 days old) are easier to peel. Egg researchers have found that ease of peeling is related to pH, a measure of acid/alkaline levels. Acidity/alkalinity determines how tightly the membranes between the white and the shell are bonded together. Older eggs, which have lost some of their carbon dioxide on standing, are more alkaline, with a pH of 8.7 to 8.9 or higher, and are much easier to peel.
Yolks of fresh eggs don't discolor readily. Although older eggs are easier to peel, they are more prone to the ugly discoloration around the yolk. This greenish-gray layer on the surface of the yolk is caused by the combining of iron in the yolk with sulfur in the white.
Heat, which speeds up many chemical reactions, is the primary cause. The longer the heat is on the egg, the greater the opportunity for these two chemicals to combine. Careful timing and the cold-water rinse to stop the cooking are excellent techniques to combat the green surface.
Alkalinity is also a factor. This reaction is slowed or prevented by acidic surroundings. Older eggs that are more alkaline (less acidic) and easier to peel are, unfortunately, more susceptible to discoloration. Using the recommended 15-minute standing time and an immediate cold-water rinse, you should not have any discoloration, even with older eggs.
An acidic sauce can repair some of the damage. Acids react with this green iron sulfide, changing it back to egg-colored substances. So even if you have overcooked eggs with badly discolored yolks, mixing them with acidic ingredients like mayonnaise with a little lemon juice will greatly reduce the discoloration.
Deviled eggs or sliced eggs are more appealing if the yolk is centered or at least not off to one edge. Researchers have found that eggs stored on their sides have the most consistently centered yolks (eggs stored large end down came in second). Some recommend cooking eggs in an upright position; you may have seen little wire holders or racks designed to hold an egg or several eggs upright in the pot.
At the Cordon Bleu Cooking School in London, students are instructed to twirl the eggs for several minutes at the beginning of cooking. Researchers have confirmed the validity of this technique and rollers are used to hard-cook eggs commercially. Few of us at home have the patience for twirling eggs. You can do only one at a time, which makes it out of the question for a large batch.
I prefer another technique. The night before hard-cooking eggs, I turn the carton -- tightly closed -- on its side. If you have an egg rack, cooking them standing up is effective, too.
Starting the eggs in tap water reduces the chance of the shells' cracking, but inevitably some do. Adding vinegar to the cooking water will speed up coagulation and seal any cracks fast, but it also will make the eggs more difficult to peel. Adding salt, which speeds up coagulation, is a much better solution (1 teaspoon for small batches, or 1 tablespoon for big batches).
Piercing the eggs at the broad end, where the air sack is, seems to encourage rather than prevent cracking unless the eggs are very old. Researchers report that out of batches of five dozen at a time, 5 percent of those that were not pierced cracked, while 55 percent of the pierced eggs cracked. With very old eggs that have a large air sack, piercing may be helpful.
Eggs are best kept in their carton, which holds them in an upright position and offers some protection from refrigerator odors. Cartons should be stored on a stable shelf, not the door where eggs get jarred with each movement.
Hard-cooked eggs that are dyed for Easter are safe to eat if you can minimize the time that they are unrefrigerated. You can cook and dye them, refrigerate until ready to hide, then refrigerate after several hours of hiding, finding and collecting. Hard-cooked eggs normally keep well one to two weeks refrigerated. If the egg appears slimy or pink or smells strong, discard it immediately.
Without a dated carton, is there any way that you can tell how old eggs are? As eggs age, more and more air seeps in through the shell and the air sack at the broad end of the egg gets larger and larger. If you place an egg in a clear glass bowl of water and it lies flat on the bottom, it has a relatively small air sack and is quite fresh. If the egg stands up on the bottom of the bowl, it has a larger air sack and is older. If it bobs off the bottom, it is still older. If it floats, watch out -- it may be rotten.
The Best-Ever Deviled Eggs
Makes 24 halves or 10 to 12 appetizer servings
12 large eggs, at least a week old
1 tablespoon plus 1 1/4 teaspoons salt, divided use
3 medium shallots, minced
2 tablespoons butter
1/2 cup sour cream
1/3 cup mayonnaise
1/8 teaspoon cayenne
1/4 cup finely chopped fresh chives
grated zest of 3 lemons
3 tablespoons red caviar, well chilled (see note)
The night before the eggs are to be cooked, seal the carton with piece of tape and turn it on its side to better center yolks.
When ready to cook, place eggs in a medium saucepan. Add water to cover by 1 1/2 inches. Add 1 tablespoon salt. Partially cover the pot and bring to a full rolling boil. Reduce heat to low and leave on heat, covered, 30 seconds. Remove from heat and let eggs stand, covered, in hot water 15 minutes. Pour off hot water. Rinse eggs under cold running water for 5 minutes. Pour off water. Shake pan to bump eggs against each other until all shells are well cracked. Cover with cold water.
Peel eggs under running water, rinse them and cut in half lengthwise. Transfer yolks to a bowl. Cover and chill yolks and whites separately 1 hour.
Saute shallots in butter in medium skillet over medium-high heat until soft, about 2 minutes. Set aside.
Mash yolks with a fork. Mash in sour cream. Add mayonnaise, 1 1/4 teaspoons salt and cayenne. Whisk until well blended. Whisk in shallots.
Fill egg white halves with yolk mixture, extending mixture over part of the white. Generously sprinkle each stuffed egg with chives, leaving a little yellow showing around edges. Sprinkle eggs with lemon zest. Cover and refrigerate.
When ready to serve, spoon a bit of cold caviar onto each half. Serve well chilled.
Note: If you do not like caviar, you can leave it off. They are still wonderful. But you should try them at least once with the caviar. You may find that you like it.