Just how fresh is an egg? Though I’ve written lots about keeping eggs fresh, all I could have told you about checking for freshness is – if the shell looks very solid, opaque and feels slightly bumpy the egg is fresher than one that feels very smooth. Then I happened across a book called How to Boil and Egg, by Rose Carraini. The book is a beautiful combination of auther paintings and good tips on using eggs. I loved the recipe but what I remember most is her tip for testing eggs. I tried her test and can assure you it works;
Put the egg in a cup or bowl and cover it with cold water. If it stays just below the surface and horizontal, it is very fresh. If it tilts slightly upward it may be as old as ten days, if it floats vertical, open it separately before using, if floats high in water – toss it!
This is a useful thing to know when you are shopping for eggs to last through an ocean passage. Not only do you want eggs that have never been refrigerated, you want them to be very fresh. If I don’t know the vendor and had no proof the eggs have been hatched within the past few days, I’d buy a few and test them. For any eggs I have had on board more than a few weeks, even if I have cared for them very carefully, I use the precaution recommended by Rose and open each egg separately, pour it into cup to be sure it is okay, then add it to my batter rather than let on bad egg spoil the whole cake.
Since we are on the subject of eggs afloat, here’s what I wrote on the subject in The Care and Feeding of Sailing Crew, 4rd edition
On Preserving Eggs
Every cruising cookbook will mention some way of preserving eggs on long voyages. I’ve personally heard of five basic ones; the choice depends on your pattern of thinking.
1. Grease each egg carefully and thoroughly with Vaseline.
2. Paint each egg with sodium silicate (water glass).
3. Boil each egg 10 seconds.
4. Deep-freeze the eggs.
5. Turn over the eggs every two or three days.
The first three methods are slightly messy and consume time when you are busiest—preparing to leave port. Greasing must be done carefully, as any void in the coating will allow the eggs to rot. Overboiling will cook the eggs so they are not good for cakes or baking, and you won’t find this out until you actually break open an egg you are about to use. These methods require no extra maintenance once you are at sea other than removing the Vaseline if you choose method 1. Neither Vaseline nor sodium silicate is dangerous to your health if a small amount should get into your food while you are breaking an egg.
Freezing works perfectly, and that is how eggs are kept in many countries where they must be imported. You can tell an egg has been frozen if it has a pale yellow yolk. If your freezer fails and the eggs even begin to defrost, they’ll start going bad in five or six days.
Turning the eggs is the method I always choose. All I have to do before we leave port is store away the eggs in regular egg cartons. Then at sea, it’s necessary to remember to turn over each carton three times a week. There is a chance of failure with this method. If the eggs aren’t turned over because you forget, or because you are too seasick, they’ll start to deteriorate. If they sit for a week without turning, they’ll start to go bad after 25 days or so.
The reason all these methods work is that they keep air from entering the semiporous eggshell. When an egg is absolutely fresh, its shell is well coated inside by the clear egg fluid, and air can’t get through. As it ages, the shell dries out inside where the air space sits, and then the shell becomes more porous. Vaseline and sodium silicate add an airtight barrier to the outside of the egg. A 10second boil adds an internal barrier. Turning the eggs works the same way—it keeps the whole inside of the shell moist.
Whichever method you choose, buy the freshest eggs you can find—ones that have never been refrigerated or kept in an air-conditioned room. Two or 3day-old eggs tend to have lumpy shells that are absolutely white and opaque. After five or six days of storage, even in refrigeration, the shells start to develop small, slightly gray spots that are easily visible if you hold the egg up to a strong light. Supermarket eggs are a poor choice: (1) these are usually bought from a central egg distributor and are at least three days old when they reach the store, and (2) they are almost always transported in air-conditioned trucks. This is vitally important. A 20degree increase in temperature will drastically affect the keeping quality of eggs. If you are sailing from a cold climate such as England, New England, or Canada, bound for the tropics, your eggs won’t last much longer than 25 days. So buy just enough to last until you reach warmer waters, such as in Spain, Bermuda, Hawaii, or Mexico. Then buy your egg supply. Going the other way, there is no problem.
Don’t wash your eggs before you store them away. They have a natural protective covering, and it’s water-soluble.
Store your eggs in the coolest part of the boat, somewhere below the waterline if possible and close to the hull but away from the heat of the engine. Water temperature in the tropics rarely gets above 76 degrees, and eggs keep naturally at this temperature; with no preserving methods at all, they will last nicely for two or three weeks.
No matter how you keep your eggs, they will change slightly as they age. After 12 to 25 days (depending on the temperature of your storage locker), the yolks will become fragile, and making sunny-side-up eggs will be a challenge. After 25 to 30 days, the eggs will only be good for scrambling, boiling, or baking. After 30 days, the whites of hard-boiled eggs may have a slightly yellow or brown tinge and the yolks will be pale in color. This doesn’t change the eggs’ cooking value, nor does it affect the flavor. But if the egg is cracked, or has a dark appearance right through the shell, I wouldn’t use it. After you’ve kept eggs 15 days, I’d also suggest breaking each egg separately into a cup so that a bad egg won’t spoil a whole cake mix or a 10egg omelet.
The longest I’ve had eggs last by turning them over three times a week is three months. Then I ran out of eggs. Out of the 144 eggs I’d started with, only five went bad—the first one 25 days out, the second after 45 days. But either of these eggs could have had a small crack in its shell.
Don’t throw away egg cartons. They might not be available in the next country you visit. Save any Styrofoam ones you get; they’ll last better than pressed paper ones and can be washed if necessary. Pressed-paper egg containers also seem to promote mold on the eggshells. In Mexico, the Mediterranean, and the Far East, you can buy plastic egg carriers in 1dozen and 2dozen sizes. These are great. They’re sturdier than Styrofoam, have a good carrying handle, and are quite crush-resistant. I still have one I bought in Mexico nine years ago.
As for quantity, I take as many eggs as I have room for. Eggs are a real bargain worldwide. A dozen of them cost less than one 12ounce can of corned beef, yet they can be a main course for five or six people. I figure on a minimum of two eggs a person per day on real long passages, one and a half a day on 1,000mile voyages. When most of your other perishables are an ancient memory and cans are the reality, eggs in all forms still taste fresh—eggs and egg salads, deviled eggs, omelets, custards, soufflés, cookies.
For our voyage south from Virginia and then around Cape Horn, I wanted provisions to last for up to 60 days at sea. I purchased small packets of powdered whole eggs from a camping supply store. They have since become a staple on board—not a substitute for fresh eggs, but a supplement. They are easier to handle than fresh eggs for baking projects—i.e., just add tablespoon of egg powder and 1/4cup of water to any recipe calling for a whole egg. They make fine scrambled eggs if you add a few drops of vinegar to the recommended mix plus some fresh or dried parsley, then beat well with a wisk before cooking. One caveat: The soft paper and foil packets are susceptible to leakage, so I store my spares in Ziploc bags until I need them. With powdered eggs on board, I can reduce my fresh egg supply by about a third