Baking – Do eggs have to be very fresh for baking

I've been told that the shiny side should go on the inside for cooking, and the outside for freezing. In other words, do you want to reflect the heat into the food, or away from the food?

However, common sense (which fails very often) tells me that with the temperature ranges involved, any benefit is marginal, if it exists at all.

The only time it might matter, is if you were trying to warm something up in the sun. Then it might make a difference.

EDIT: From The Straight Dope:

The truth is that the shiny side is not treated with a dangerous chemical. Mineral oil is used as a lubricant during the rolling process, some trace of which may remain on the finished foil--but it's not dangerous. The shiny side is shiny because of the way foil is made. During the last pass through the rolling mill, a double thickness of foil is run between the rollers. The side of each sheet that comes in contact with the polished steel rollers comes out shiny. The other side has a matte finish.

http://www.straightdope.com/columns/read/1135/should-a-baking-potato-be-wrapped-in-foil-shiny-side-in-or-shiny-side-out

ALSO

The official word from the Reynolds aluminum people is as follows: "It makes little difference which side of the Reynolds Wrap aluminum foil you use--both sides do the same fine job of cooking, freezing, and storing food. There is a slight difference in the reflectivity of the two sides, but it is so slight that laboratory instruments are required to measure it."

Per Harold McGee, in On Food and Cooking (page 86 of the 2004 edition), there is no truth to this common assertion.

Acids and salt do pretty much the same thing to egg proteins. They get the proteins together sooner, but they don't let them get as close together. That is, acids and salt make eggs thicken and coagulate at a lower temperature , but actually produce a more tender texture.

McGee explains that the salt separates into ions, which cluster around the charged regions of the egg proteins, allowing them to get closer before being denatured because they don't repel each other. This causes them to bond together earlier, before they become unfurled and could form tighter (and thus tougher networks).

McGee concludes:

So eggs end up more tender when salted, and especially when acidified.

So salt them when you beat them, or in the pan, in practice it will make little difference compared to many other factors, such as the temperature and technique with which you cook them.