Kosher salt is salt inspected and blessed by a Rabbi. It is non iodized and generally thought to be best for pickling.
kosher dissolve faster than table salt, this way when you salt your food you get the salty taste right away, with table salt it takes a while to dissolve and you may keep adding salt then it's too salty
and table salt has 25 % D.R. of sodium - 1/4 t. kosher has 20 %
Kosher salt can be any of several things.
Babbie is correct when she mentions the chemical properties of the product packaged as Kosher Salt. It is also more coarse than table salt, and for this reason makes a good abrasive when cleaning. Different salts have subtly different flavors as well; my favorites are sea salt and kosher (pickling) salt, which is called kosher salt because it's used when making kosher dill pickles.
ThriftyFun is, forgive me, mistaken. Making something kosher -- a factory, a kitchen, or a food -- doesn't involve blessing anything. Kosher means "fit, proper, legal." So what is Kosher? When asked, we smile politely and set the record straight. "No, the Rabbi does not bless the production process." Food is Kosher when its ingredients and manufacturing procedures conform with the Jewish dietary requirements. These requirements are outlined in the Torah and further clarified in the Shulchan Aruch. Once these dietary requirements are met, the food may be eaten and enjoyed by Jewish consumers. The appropriate blessing over the food (which is to say, the praise of the creator of the given type of food, not praise of the food itself) can now be recited before beginning to eat.
If you're curious, kitchensavvy.typepad.com/
Babbie got kosher salt and table salt exactly backwards. I apologize for saying otherwise. Kosher salt is used for kashering meat (making kosher-slaughtered meat fit to eat by removing the blood from it) precisely because it does NOT dissolve as quickly as regular table salt. My bad.