To cure the brisket, you will need a large earthenware, enamel, or stainless steel crock. Pour the water into the crock and add the salt, stirring to dissolve it. Add the egg. The egg is used to test the salt content of the brine. If the egg floats in the solution, it is ready. If it does not float, continue adding salt a little at a time, stirring to dissolve, until the eg