All About Eggs
Basic Skills Unit I: Hard-Cooked Eggs
Steven A. Shaw
Hard-cooking an egg (we will use the term hard-cooked rather than hard-boiled because it's more accurate) seems like just about the simplest thing in the world, and if you drop an egg into boiling water and boil the heck out of it for awhile you will indeed produce a hard-cooked egg.
But it may not be a good one. It may crack while you're cooking it. It may be difficult to peel. And the yolk may take on a greenish cast.
These are the three issues with hard-cooked eggs that we'll try to tackle today, and then we'll tackle a few more.
How to keep eggs from cracking during cooking
There are two main reasons eggs sometimes crack when you hard-cook them:
First, they sometimes crack on account of impact with the cooking vessel, or each other.
Plan A: I have found that the best way to avoid this issue altogether is to place the eggs in the pot before adding the water. This works for me because I have an extension on my faucet that brings water directly to the stovetop. You may have one of these, or you may have a pot-filler spigot on your sink, or you may just wish to fill the pot from a pitcher. If you don't wish to approach it that way, I suggest you avoid taking a whole pot of eggs to the sink to fill -- the jostling about presents more of a risk of cracking than is necessary.
Plan B: Because the preferred method for hard-cooking eggs starts with cold water (more on the reasons for this later), you can simply place the eggs in the water with your hand. You need to place them in the water, though -- most people I've observed doing this simply drop them in, so they fall to the bottom and often get damaged. Stick your hand right in there and gently lay the eggs on the bottom.
Plan C: If for some reason you're in a rush and you have a pot of liquid already at a simmer, the best tool I've found for placing eggs in the pot is a pair of standard kitchen tongs. You can also, if you get the right angle, use a spoon to lower the eggs and gently roll them onto the bottom of the pot.
Do not under any circumstances place the eggs in multiple layers in the pot. This will almost certainly cause cracking as the eggs hit one another. Only cook as many eggs in a pot as can fit in one loose layer on the bottom.
The second reason eggs often crack during hard-cooking is that they usually have an air pocket at the large end. As we've mentioned several times in the introductory materials, this air pocket forms as the two layers of the shell membrane separate on account of the egg's temperature and moisture loss. When this air pocket is heated, it expands and can break open the shell. (Why doesn't the rest of the egg expand and break over the shell? Because the liquid portions of the egg are roughly 800 times as dense as air and therefore barely expand at all when heated just a couple of hundred degrees.)
The most straightforward recommendation for addressing the air-pocket problem -- and this has been repeated in a million books -- is to eliminate the air pocket by piercing the eggshell. You simply take a pin -- a safety pin is easiest to hold, or there are dedicated egg-piercing devices available at housewares stores for about a dollar -- and make a hole in the large end of the egg. When you cook the egg thus pierced, you will actually be able to see air bubbles coming out of this little hole -- that's the air that could have cracked your egg. The latest wisdom from the egg experts, however, indicates that piercing has two drawbacks: first, it can create micro-fractures around the piercing site and thus actually increase the risk of cracking; and second, the needle can introduce bacteria and provide a site for bacteria to enter the egg if it is held after cooking. Neither of these problems has affected me, but it's up to you to decide if you want to bother with pricking. I don't.
Pricking works, but is probably unnecessary if you follow all the other guidelines presented here
For the most part, starting with cold water is sufficient protection against cracking caused by gas expansion, and it certainly saves you the time and inconvenience of all that pricking: if you throw a cold or room-temperature egg into boiling water, the air pocket expands rather quickly. If you bring the temperature up slowly from cold, even if you don't prick the egg, you will reduce your risk of breakage because the egg may have time to exhale a bit of gas through its many small pores.
Some people throw a bit of white vinegar into the water. For hard-cooking, this isn't particularly necessary. It won't actually prevent the eggs from cracking. What it will do is help the whites coagulate if the eggs do crack (technically, vinegar does not aid coagulation but, rather, lowers the temperature at which coagulation occurs). But if you follow all the above guidelines, the addition of vinegar will be like a belt atop suspenders.
While we're on the subject of water, it's important to use enough of it. Cover the eggs by at least one inch and preferably two, and make sure there's enough space so that the water can actually circulate around the eggs -- if they're all jammed up against one another you can get spotty results, and if there's not enough water there won't be enough thermal energy to cook the eggs properly.
How to produce easy peelers, and how to peel them
There are two main strategies for ensuring that your hard-cooked eggs will be easy to peel:
First, avoid too-fresh eggs. The same process that causes an air pocket to form between the two layers of the shell membrane is a great ally when it comes to peeling hard-cooked eggs. Having experimented a bit, my suggestion is that you aim for eggs to be around a week old when you hard-cook them. That's not a week from purchase but, rather, a week from picking and packing -- you can use the Julian date on the carton to figure this out, but a safe rule of thumb is that in a high-turnover American supermarket your eggs will already be around 4 days old when you get them. So give your eggs 3 or so days before you hard boil them, and they will be easier to peel.
Second, shock the eggs with cold water when they're done cooking. You can either transfer the eggs into ice water with a slotted spoon or tongs, or you can put the whole pot in the sink and run cold water over them until they've cooled significantly. This shock will cause a slight contraction of the egg inside the shell, making the shells easier to remove. But you have to act quickly. If you leave the unpeeled eggs sitting in the shell for too long, they will again become difficult to peel.
Peeling methods vary, but most everybody agrees (as do I) that eggs peel better if you do them either under running water or submerged in water. In terms of the actual approach to peeling, the people who seem to have done the most research recommend crackling the egg all over by repeatedly knocking it gently against the counter, then rolling the egg between the palms to further loosen the shell, and then starting at the large end and peeling downwards. I personally have found that it's a waste of time to do all that crackling -- indeed, many of the methods recommended by the experts tend to be unworkable if you have to do, say, four dozen eggs at once. I just give the large end of the egg a few taps against the counter or the bottom of the sink and I start peeling under running water. The first few little pieces come off with some difficulty, usually, and then as I go down the egg the rest tends to come off easily in big pieces. If that doesn't work for a particular batch of eggs, though, I suggest you revert to the crackle-and-palm method.
Peel hard-cooked eggs under cool running water or with the assistance of a bowl of cool water
Piercing, discussed above, can also be helpful in this regard: it can allow some water to enter the egg, creating a layer of fluid that enables easier peeling. But, again, I don't find that it's necessary or worth the trouble. If after following all the other guidelines here, however, you're still having trouble, I think the piercing trick will put you over the top. Use a clean needle, though.
The color of the yolk
The reason egg yolks sometimes acquire a greenish cast is because of a sulfur and iron reaction that happens at near-boiling temperatures. The main way to avoid it is to make sure your eggs never actually boil. That's why I don't like to call them hard-boiled eggs.
This is what you don't want your hard-cooked egg to look like
You can handle this one of two ways:
Starting with cold water, bring the eggs near to the boil and, just as a rolling boil is about to set in, remove the pot from the heat (or just turn off the burner), and let it sit covered for 12 minutes. It helps, in this regard, to have a pot with a see-through lid. If you don't, and if you're not particularly familiar with how long it takes to boil various quantities of water on your burners, I suggest you go with uncovered so you can watch. If your eggs hit a hard boil for any significant period of time, my experience has been that they are likely to discolor. I use the 12 minute number because it works well for me with Large eggs (the American Egg Board recommends 15 minutes, but that strikes me as too long -- we recently experimented with eggs cooked for various lengths of time and found that 12 minutes or even a little less will be just fine). I recommend departing upwards or downwards 1-2 minutes per size: around 10 minutes for Medium, 13-14 minutes for Extra Large, and 14-15 minutes for Jumbo. There's a lot of leeway in these guidelines, though, and your eggs will come out fine if they spend an extra couple of minutes in the water.
Or, starting with cold water, bring the eggs near to the boil and, just as a rolling boil is about to set in, turn the heat down so you achieve a gentle simmer, and cook the eggs for about 9 minutes (with the same adjustments per size above).
Either of these methods will give you attractive, yellow, tender eggs. (In addition to ruining the color of the yolks, a hard boil will make the whites rubbery.)
The wrong way (left) and the right way (right)
It's a total pain to peel a hard-cooked egg that has been refrigerated for any significant length of time. Yet the food-safety recommendation is not to store peeled eggs. I personally disregard this recommendation: in a tightly sealed container, in a home refrigerator, working under clean conditions with clean hands, I'm willing to take the risk of storing peeled hard-cooked eggs. You can decide either way, but you're not going to be happy if you store them unpeeled. If you don't want to store peeled eggs, just cook as many as you're going to use that day and then cook more as needed.
If you want to slice hard-cooked eggs in half and lay them on a platter, there are three presentation issues to bear in mind.
First, centering of the yolk. Most of the time, if you've done everything else right, the yolk will be fairly well centered in the egg. But once in awhile you will see some yellow at the surface and this means the yolk is off center. If you slice directly into the yolk at that point, you will wind up with a cosmetically defective egg-half.
An off-center yolk showing through
An off-center egg-half
If you encounter an off-center yolk, starting with the visible yellow part at the top of the egg, rotate the egg 90 degrees along its axis. Then cut. You will wind up with one half containing a larger portion of yellow than the other, but the yellow will be centered in the white.
Second, cutting. A crinkle-cut garnishing knife is a nice tool to have if you're cutting and serving hard cooked eggs. These knives come in various depths-of-crinkle and make for an attractive presentation.
Shallow garnishing knife
Deeper garnishing knife
Third, garnishing. Egg halves will benefit greatly from a sprinkling of coarse salt and a grind of white pepper. In addition, a finely chopped green herb or a single herb sprig may appeal to some.
Cooking with hard-cooked eggs
A hard-cooked egg is complete in and of itself, but it can also be the basis for many excellent (and usually simple, quick, and convenient) recipes.
Eating them straight
If you haven't done it in awhile, I recommend you eat a well-prepared (using all of the above guidelines) hard-cooked egg straight, while still a bit warm, with just some coarse salt sprinkled on between bites. If you're like most people, you've forgotten how delicious and satisfying this can be. On occasion, a hard-cooked egg is a lunch for me, accompanied by whatever other snacks I have lying around in the kitchen.
As garnishes and additions to other dishes
Beyond eating them straight, halved or quartered hard-cooked eggs are excellent additions to salads as well as to many dishes where you don't typically see hard-cooked eggs: served atop pasta, or sauteed spinach, or just about anything. They are quite versatile.
Moving slightly upwards in the scale of hard-cooked egg cookery, we get to egg salad. I believe our friends in the UK call this "egg mayonnaise" -- at least that's what they call an egg-salad sandwich at Pret A Manger. Egg salad is simply a mixture of chopped hard-cooked eggs and mayonnaise, with perhaps a bit of salt and pepper added. I love egg salad because of that combination of hard-cooked eggs and a luscious egg-derived sauce (mayonnaise is, indeed, a sauce and if you need a refresher course on how to make it you can review Jack Lang's eGCI class on the subject).
There are only a couple of variables in the basic egg salad: the type of mayonnaise, and the way you chop the eggs. Egg salad comes out very well with commercially prepared mayonnaise, but it will taste even better if you make it with homemade mayonnaise. You can also make it with many of the derivatives of mayonnaise, such as garlic aioli. In terms of chopping, there are many ways to do it and I have no preference: a rough chop with a knife is nice, as are the uniform cubes you can get with a dedicate wire-mesh egg slicer/chopper. When making a portion for one person, though, I just mash the egg and the mayo together with a fork, add a little salt and pepper, and eat.
You can add most anything to your egg salad: herbs, olives, scallions, pimentos, and even other salads like potato salad.
The ratios you use in making egg salad are highly flexible, but a good rule of thumb is 1/4 cup of mayonnaise for 4 Large eggs -- in other words 1 tablespoon per Large egg. I like to use more than that -- almost twice as much -- but I've heard tell that my egg salad is too "wet" for some people's tastes.
Deviled eggs are pretty much the pinnacle of hard-cooked egg cookery. If you haven't served them at a party in awhile, you'll be amazed at how quickly they get devoured. Don't be surprised to see some guests eating eight or more halves of an egg.
For deviled eggs, you cut the hard-cooked eggs in half (you may still wish to use a garnishing knife as discussed above -- it will give an interesting appearance to the whites) and separate out the yolks. You then add, at a bare minimum, mayonnaise and prepared mustard to the yolks, mix them up, and pipe them back into the whites. Salt, pepper, herbs, and lemon juice will improve them as well.
In terms of ratios, I recommend 1 tablespoon of mayonnaise and 1/4 teaspoon mustard per 2 hard-cooked yolks. Salt, pepper, herbs, and lemon juice should be added to taste, not according to any particular formula -- but the amounts should be pretty small.
I think you'll also very much enjoy your deviled eggs if you replace half the mayonnaise with some other kind of fat. For example, on New Year's Eve this past year, Dave-the-Cook and I, following the lead of Guajolote, prepared deviled eggs with half goose-fat and half mayonnaise -- and we garnished them with duck cracklings. They were very good.
To mix the yolks with the mayonnaise or fat, you can just use a fork for small quantities. You can also pack the ingredients into a Zip-Loc-type bag and mash them together by hand. For larger quantities, though, you'll probably be happier using a KitchenAid-type mixer.
If you don't want to use a pastry tip, you can still pipe out very respectable deviled eggs with a plastic bag. Just pack the bag with the yolk mixture and squeeze it down to one corner, then snip off the corner to make about an 1/8 - 1/4 " hole. This becomes your pastry bag. It's also the best way to transport deviled eggs: keep the yolks and whites separate, and pipe the yolks into the whites when you reach your destination.
Thanks for joining in this part of "All About Eggs." Tomorrow, we poach.
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