The best way to keep eggs fresh is to keep them in the chickens. This is one of the benefits of having your own backyard flock, along with pest control and entertainment.
One of the problems with home flocks, though, is that you get too many eggs in spring and not enough in winter. A consistent supply requires a method of preservation.
Two primary things cause eggs to go bad: bacteria penetrating their shells and causing decomposition; and liquids inside the egg evaporating out through the shell.
Fresh, unwashed eggs have a cuticle, or membrane, called the “bloom”. It helps seal their porous shells, slowing down bacteria going in as well as liquids evaporating out.
Cool temperatures will further slow down bacteria.
Assuming that you are starting with eggs collected from your own nesting boxes on the day they were laid, and that they are clean but not washed, you can reasonably expect them to last well over a month at room temperature, and around six months in a refrigerator.
So, refrigeration is the obvious solution.
But perhaps there isn’t room in your refrigerator for twenty or thirty dozen eggs. Or perhaps electricity is unreliable where you live. What a pity it would be to lose your annual stock to a power outage.
In 1898, Canada’s Department of Agriculture began a 15-year experiment with 25 different methods of preserving eggs, and concluded that immersion in limewater was “the most satisfactory".
Two other methods were nearly as effective: coating with Vaseline, and immersion in “waterglass" (sodium silicate).
Vaseline, however, tended to impart its own flavor, and who wants Vaseline and bacon for breakfast? And waterglass is somewhat expensive and unpleasant to work with.
So if you want to preserve eggs, and you don’t have refrigeration, limewater is your best option.
“Limewater" is the common name for a saturated solution of calcium hydroxide, Ca(OH)2. It is strongly alkaline, which will inhibit bacteria, but it won’t react with the egg shell and affect taste.
A saturated solution can be made by mixing one ounce (about three tablespoons, or two heaping tablespoons, or 28 grams) of calcium hydoxide with one quart of water. (It’s easiest to make a paste first. Then pour the “milk of lime” into the remaining water, and stir it, or shake it in a jar.)
Keep it well-mixed for a few hours, then allow it to settle. Some solids will precipitate out of the solution. The liquid left above is saturated. This is your “limewater", ready to be poured off to cover your eggs.
A quart of limewater is about the right amount for a half-gallon container once the eggs have been added.
Use clean-but-unwashed eggs fresh from your nesting boxes. (Dirty eggs should be washed and used rather than preserved. Store-bought eggs won’t keep well because they’ve been washed, which removes the protective “bloom” from the shells. Besides, they may already be weeks old by the time you buy them.)
Place the eggs in a wide-mouth jar, fill it to the top with limewater, which should be quite cold, and screw on the cap to prevent dehydration.
A half-gallon jar will hold up to 18 eggs depending on size; a gallon jar up to three dozen.
Make sure all the eggs stay completely submerged.
Store in a cool, dark place.
Rinse the eggs when you take them out for use.
After six months the yolks will be flatter and the whites runnier than fresh, but the taste will still be almost as good.
After about eight months, quality seems to degrade.
After a year, there will be a noticeable difference in flavor and texture, but they’ll still be okay fried or scrambled. You won’t notice the difference in baked goods.
Eventually the whites will darken slightly, and the eggs will take on a slightly stale - but not rotten - smell. But they will still be useable for at least baking.
Use only the highest quality, freshest, unwashed eggs. You get clean eggs by keeping your nesting boxes clean.
Date your containers, and try not to move them - if one egg cracks, it’ll ruin the whole batch.
Duck eggs will keep longer than chicken eggs due to their thicker shells.
Do not re-use limewater; make a fresh batch every year.
When in doubt about the edibility of an egg, do the “Sink or Swim” test. If the eggs sink in water and lay flat on their side, they're still fresh. If they sink, but stand on one end at the bottom, they're not as fresh but still edible. Eggs that float have gone bad.
