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All About Eggs -- FAQ

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The "All About Eggs" FAQ

Steven A. Shaw

Questions from members

I was thrilled, on Wednesday and Thursday, to receive so many interesting egg-related questions from eGullet members. I have answered about 90% of those questions below. If you don't see your question answered here, it's probably because 1) another question covered the same material so I answered the one that arrived first; 2) your question strayed into the cookery realm and will be addressed next week in the discussions of hard-cooking, poaching, etc.; or 3) I wasn't able to find the answer to your question (this only happened in a couple of instances, and I've written to some experts in the hopes of getting answers -- I'll post those next week if they come in).


Q: My fiancé, who is from Massachusetts, remembers a commercial that claimed "Brown eggs are local eggs and local eggs are fresh." I hail from Ohio, and have never heard that commercial. I read that you said that there is no difference between a brown and a white egg other then the breed of chicken. So do the farms in New England have more chickens that produce brown eggs or was that commercial a scam? Are there regions of the country where the local chickens produce more of a certain color of egg? If so, please tell us what eggs we should buy now that we live in Virginia in order to get the freshest egg.

A: The dominant breed of egg-laying hen in use here in America today is the Single Comb White Leghorn. According to the American Egg Board, "This breed reaches maturity early, utilizes its feed efficiently, has a relatively small body size, adapts well to different climates and produces a relatively large number of white-shelled eggs, the color preferred by most consumers." In New England, however, a disproportionate number of consumers prefer brown-shelled eggs. Thus, the dominant breeds in New England are Rhode Island Red, New Hampshire, and Plymouth Rock -- which lay brown-shelled eggs. (White hens lay white eggs, and red/brown hens lay brown eggs -- there are also some hens that lay pastel-colored eggs, which also taste the same as other eggs.) These birds are somewhat larger and consume more feed than the Leghorns, so brown eggs are slightly more expensive to produce. Ultimately, though, the advertisement to which you refer (and I haven't seen it) doesn't sound particularly compelling. A date-stamped carton is far better evidence of freshness than the color of an egg.


Q: Every few dozen eggs I get a fertilized one. Is it safe to eat if I just remove the blood spot?


Sometimes in small farm raised eggs, one sees a tiny blood red spot on the yolk. I have been told that this shows the egg has been fertilized. True or False?

A: A blood spot does not indicate a fertilized egg. These spots are, simply, what they look like: blood. During formation of the egg, a blood vessel sometimes breaks, causing a spot of blood to remain on the yolk. It's safe to eat, or you can remove it with a spoon, a knife, or half of the eggshell. The reason you see more of these on small-farm eggs is that these operations don't necessarily use as advanced technology for what is called "mass candling" -- a process that detects various defects in the egg by strong illumination.

It is extremely unlikely that you will ever get a fertilized egg from a supermarket because production hens at large egg-laying operations never get anywhere near a rooster in their lifetimes, and if you get one from a small farm chances are the embryo will be too small to detect via a casual glance. Like eggs with blood spots, fertilized eggs are safe to eat -- but you probably wouldn't even know you were eating one. Some people think fertilized eggs are more healthful -- there does not seem to be any strong evidence in support of this proposition, though.

If you really, really must know whether your egg is fertilized, it is possible to do so upon careful examination and with some practice. According to Rick and Gail Luttmann, in their book Chickens in Your Backyard: A Beginner's Guide: "It's not impossible to tell whether or not an egg is fertile just by looking at it, but it's also not the casual matter some people assume. All eggs have a small white lump on the yolk called the blastoderm, which usually can be seen when the egg is cracked into a pan. People sometimes mistake this for a little chick beginning to develop.... Actually, this is where fertilization takes place, but the lump is there whether the egg is fertile or not. With close examination of the blastoderm you can distinguish between a fertile and an infertile egg. If the blastoderm is irregular and disorganized, and appears entirely opaque, then the egg was not fertilized. If it is neat and rounded with a small translucent eye in the center, you are looking at the very tiniest of baby chickens!" Thanks to Julie Layne (aka "ChickenLady") for digging this information up for us.


Q: I've heard that some recipes work better with older eggs, is this true?

A: I'm trying to avoid cookery questions in this FAQ -- we will deal with different types of whole-egg cookery next week and discuss the best egg for each task in context -- but the general idea is this: As you'll recall from our earlier discussion of grading, a really nice fresh AA egg has a very tight internal structure. It stands tall and maintains its integrity. Such an egg is ideal for poaching or frying sunny-side up. You'll also recall the discussion of the inner and outer membranes of an egg, and how those membranes begin as one and eventually get separated by an air pocket as the egg cools and loses moisture. It's not hard to imagine that such an effect makes an older egg preferable for hard-cooking: it's going to be a lot easier to peel. So, as a rule of thumb, for poaching and frying you want the freshest eggs possible, and for hard-cooking you want eggs with a week or so of age on them. Beyond that, there's little benefit to additional age and the eggs start to lose enough flavor that it's better only to buy what you'll use within a week or so.


Q: You said in the introductory materials that "In 1975 Americans ate an annual average of 277 eggs per capita. The all-time low was 233 in 1995. As of 2002, consumption had rebounded to 252." But what was the all-time recorded high?

A: 402 eggs per capita in 1945. Here's a US egg industry fact sheet detailing various production and consumption figures.


Q: How long does it take a hen to produce an egg?

A: Approximately 24-26 hours. A typical egg-laying hen lays around 300 eggs per year.


Q: How old do hens have to be before they start laying production eggs?

How many months/years do laying hens last before they stop being productive?

Is it common practice to give laying hens hormones, etc. to increase production?

Do hens past their laying period get sold for food?

A: Hens start laying at around 18 weeks of age, and under standard large-scale farming conditions they're productive for about a year before their output starts falling off.

According to the Egg Nutrition Center, a US industry group, "Growth hormones are not used in the egg industry. Neither specialty eggs nor generic eggs have hormones in them. And while antibiotics are sometimes used to treat sick birds, this is not a routine industry practice."

Older hens are slaughtered and their meat is mostly used in utility applications (canned soups, etc.).


Q: What about duck, quail, and other types of eggs?

A: They're great. The chicken egg, however, is the dominant egg consumed by humans -- the hen's efficiency has put the other egg-laying animals out of business. By all means, enjoy them if you have a source of fresh ones. For the most part, anything I say here about chicken eggs can be carried over to other birds' eggs, but I won't specifically be discussing those other types.


Q: How do you tell if an egg has gone bad?

A: It will smell bad, or be slimy. There's also a lot of lore that says a bad egg will float in water. While it's true that a very fresh egg will likely be just a bit more dense than an equal volume of water (and therefore will sink) it's not necessarily true that a floating egg is bad. As we discussed before, an air pocket forms in an egg as it cools and loses moisture. As a result, a perfectly fine 1-week-old egg could potentially float. It wouldn't be necessary to throw it out. It would just be a waste of an egg.


Q: How do you pronounce chalazae

A: ka-LAY-zee


Other questions

These are questions I've heard asked about eggs in the past, questions I received from other eGCI instructors, and questions I just thought needed to be addressed.


Q: Does a hen need to "do it" with a rooster in order to lay an egg?

A: No.


Q: Not even once?

A: No. It's just like with a female human: she's going to ovulate and produce eggs on a given schedule no matter what (in the case of a human around once a month, and in the case of a hen around once a day). The difference is that chickens don't grow their young internally -- they grow them in the egg, externally. If a rooster happens to come along and "do it" with a hen while an egg is forming, that egg will be fertilized and, if properly incubated, a chick will grow in it. Otherwise, it comes out anyway and we can eat it.


Q: Can you really tell a raw egg from a hard-cooked egg by spinning it?

A: Though I've never met anybody who actually couldn't figure out which eggs were raw (they're the ones in the carton!), it is indeed true that a raw egg wobbles (on account of the liquids getting jostled around) and a hard-cooked egg spins smoothly.


Q: What's up with double yolk eggs?

A: It happens. Some hens produce a double yolk egg every time; and occasionally a hen (particularly a young hen) will produce a yolkless egg.


Q: What are all the numbers on the carton?

A: Here's one of the cartons of eggs we used the other day:


A typical egg carton, purchased in New Jersey on January 31, 2004

The expiration date is self explanatory, but the numbers on the top are somewhat cryptic. However, they're the information you want -- the expiration date isn't particularly relevant.

The first number you see on that carton is 027. That's a "Julian date," which is a series of dates running from 1 to 365, where 1 is January 1 and 365 is December 31. The 027 on our carton means the eggs were packed on January 27. Since we bought them on January 31, they were pretty fresh. Dates in January are pretty easy to convert, but if you want to know what 204 is you can use this handy Julian date converter to determine that it's July 22.

The second number you see is 1417 immediately following the letter P. This is the plant number, which tells us where the eggs were packed. If you're curious, you can enter the plant number from any carton of eggs into this tool. I learned that plant 1417 is ISE Farms, Inc., in Broadway, New Jersey.

I have no idea what the 13 before the expiration date means. That whole line is optional under the USDA system: you don't have to put an expiration date on your eggs; only a packing date (different manufacturers use different expiration periods -- they're free to do so as long as the number is lower than the USDA's limit). Chances are the 13 is some sort of internal corporate designation that the packer uses for identification.

Those are the USDA rules. But USDA grading of eggs is actually optional, so some packers (especially smaller local ones) go with various state rules -- if your state department of agriculture has a good Web site, you should be able to find the decoding information there. If, however, your egg carton has a USDA grade shield displayed on it, as most supermarket eggs I've seen tend to, you should be able to decode the numbers using the above instructions. Note that state rules must conform at a minimum to USDA rules, so state-labeled eggs are not in any way worse than USDA-graded eggs.


Q: How long after the expiration date are eggs still good?

A: Because packers have flexibility in setting expiration dates, and because they opt for longer and shorter periods for a variety of reasons, the more relevant question is how long after packing do eggs stay good. And the answer is a long time. Especially under refrigeration, an egg that isn't smelly or slimy is most likely safe to eat for months. Certainly, you should expect that eggs will be perfectly fine for six weeks after they've been packed. Really, the greater concern is that their taste deteriorates after awhile. I wouldn't want to eat poached 2-month-old eggs but I might use them in a baking recipe.


Q: Should eggs be stored in the carton?

A: The carton is the best place to store eggs, much better than those dumb egg-shaped depressions built into some refrigerators. The shells of eggs look solid but they actually contain tens of thousands of pores through which odors can pass easily. If you leave an egg exposed in the refrigerator, it may pick up various ambient odors. Much better to leave it in the carton, which is designed to protect the egg against odors and impacts. Though even the carton won't protect you if you store your eggs adjacent to your Stilton. Occasionally, you might want to take advantage of an egg's permeability, though: for example some people like to store several eggs in a tightly closed container with fresh truffles.


Q: What determines the color of the yolk?

A: Diet. It's fairly simple to manipulate the color of an egg by adding marigolds or other foods containing xanthophylls (yellow pigments) to a hen's diet. Eggs in the US are the color they are because that's the color consumers seem to like. In Europe for whatever reason they like their eggs to be more orange in color. It's theoretically possible to make an egg with virtually no color, for example by feeding a diet of white corn. There's not necessarily a connection between color and flavor, though there can be. In the US, it's unlawful to add food coloring as such to chicken feed -- though this would be an effective strategy for coloring eggs.


Q: Are organic, "vegetarian," free range, etc., eggs preferable to regular supermarket eggs?

A: They may be preferable to certain individuals from a social justice, political, environmental, or other standpoint, but they don't necessarily taste any different. Some of the best eggs I've had have been from small farms, but they haven't been organic or free range -- and I think most of the superiority in flavor is attributable to the fact that I had them at the farm before they got wrecked by processing, transportation, and refrigeration. When purchasing from a supermarket, bear in mind that the fancier brands have lower turnover -- your label-reading skills should come in handy when it comes time to make that determination.


Q: What exactly do the designations "free range" and "organic" mean? What about "cage-free"?

A: I think that relying on label terminology -- without more -- is not particularly wise. "Organic," for example, refers mostly to feed and supplements, not humane treatment or flavor. I've visited an industrial egg producer -- it wasn't a nice place -- but you can raise hens organically and still abuse them in most every evil industrial manner. Likewise, "free range" hens (there's no such thing as a free range egg outside of cartoons, of course) may only roam free for a short time each day, or during some seasons, and their roaming space may be a five-foot patch of concrete. Other terms, like "cage free," "natural," and "sustainable" are difficult to verify and equally susceptible to abuse. Unfortunately, there is no label term that means exactly "These eggs came from chickens that were raised in a nice way, and they taste really good."

At the same time that lousy eggs can carry fancy designations, a wonderful small farmer might very well produce top-quality eggs from humanely treated chickens yet not qualify for an organic designation. I met a farmer in Manitoba in summer of '02 and really enjoyed touring his egg-laying operation. The chef I was traveling with took some of this guy's eggs back to the restaurant and we cooked them up -- they were amazingly good. I suppose, were I to live there, I'd always buy my eggs from that guy. They're not free-range and I don't think they're organic, but they're a product I'd choose over other products and pay a premium for. If I meet someone locally here in New York who produces up to that standard, I'll buy from that person whether the eggs have a special designation or not. But I'd much rather buy from a small farmer I trust than from a stranger with an organic or free-range designation.


I hope you've enjoyed the "All About Eggs" FAQ. Next week, we'll actually be cooking eggs. Lots of them. So if you go out this weekend and purchase about four dozen of them, you'll be all set to participate in next week's units. See you then.

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