(from Storey's Guide to Raising Chickens)

Thermostabilization:

Thermostabilization was regularly practiced by housewives during the
late 19th century. Heating destroys most spoilage-causing bacteria
on the shell and seals the shell by coagulating a thin layer of
albumen just beneath it. When the egg cools, the coagulated albumen
sticks to the egg membrane and cannot be seen in the opened egg.
Unlike oiling, this method does not affect an egg's foaming
properties.

Process eggs the day they are laid. Heat tap water to exactly 130
degrees F (54 degrees C). Use a thermometer, since the temperature
is critical--the water must be just warm enough to destroy spoilage
organisms but not hot enough to cook the eggs. Place eggs in a wire
basket (such as a vegetable steamer or pasta cooker). Submerge the
eggs in the water for 15 minutes if they are at room temperature, or
18 minutes if they have been refrigerated. Lift the basket and
thoroughly drain and dry the eggs. Thermostabilized eggs will keep
for two weeks at 68 degrees F (20 degrees C) and eight months at 34
degrees F (1 degree C).


Thermostabilization and Oiling:

Thermostabilization destroys bacteria and protects albumen quality.
Oiling minimizes weight loss due to evaporation and preserves yolk
quality. Combining the two improves an egg's keeping qualities
compared to either method alone. You can thermostablize eggs and
then oil them, or combine the two procedures into one. For a
combination operation, heat oil to 140 degrees F (60 degrees C) and
hold it at that temperature. Using a pair of tongs, rotate each egg
in the hot oil for 10 minutes, then set the egg on a rack to drain.
As with simple oiling, albumen foaming properties are reduced by
this process, making these eggs unsuitable for cake baking.


Water Glass:

Submerging eggs in water glass was the preferred method of storage
during the earlier part of the 20th century. Water glass is a
syrupy concentrated solution of sodium silicate, available from a
drugstore. Its purpose is to minimize evaporation and inhibit
bacteria. The water glass imparts no taste or odor and--although it
causes a silica crust to develop on the outside of the shell--does
not penetrate the shell.

Put eggs in water glass the same day they are laid. Candle them and
eliminate any with blood spots or meat spots. As with the other
processes, use only clean (not cleaned) eggs that are free of
cracks. place the eggs in a scalded glass jar with a tight fitting
lid. A 1-gallon jar will hold about 3 dozen eggs.

Combine 1 part water glass to 10 parts boiled water. If the
solution is not diluted enough, it will become a gel that makes
handling the eggs more difficult. Mix the solution thoroughly and
let it cool. Slowly pour the cooled liquid over the eggs until the
solution covers the eggs by at least 2 inches (5 cm). Do not save
leftover solution. Screw the lid onto the jar to prevent
evaporation. If you don't have many eggs at one time, continue
adding eggs and fresh solution until the jar is full, always making
sure the solution is at least 2 inches (5 cm) above the eggs.

Store the jar in a refrigerator, basement, or other cool place where
the temperature is preferably not over 40 degrees F (4.5 degrees
C). At 35 degrees F (2 degrees C), eggs in water glass will keep
for 6 months or more. If you wish to hard cook an egg, poke a tiny
hole in the big end to keep the shell from cracking as a result of
the silica crust.

Even at room temperatures as high as 55 degrees F (13 degrees C),
eggs in water glass will keep for several months and be satisfactory
for cooking. Under the best storage conditions, water glass causes
eggs to lose their fresh flavor and take on a flat taste. The
whites will eventually get thin and the yolks will flatten, making
them less suitable for frying or poaching than for scrambling or
using in a recipe.

