Genre: Instruction

Freshness How recently an egg was laid has a bearing on its freshness but is only one of many factors . The temperature and humidity level at which the egg is held play their parts as well . These variables are so important that an egg one week old , held under ideal conditions , can be fresher than an egg left at room temperature for one day . The ideal conditions for egg storage are temperatures between 35 and 40oF ( 2o to 4oC ) and a relative humidity of 70 to 80 % . Proper handling means promptly gathering and washing the eggs within a few hours after they 've been laid . Most commercially produced eggs reach supermarkets within a few days of leaving the laying house . If you and your market handle eggs properly , they 'll still be fresh when they reach the table . It 's a misconception that you can judge freshness by placing an egg in salt water . A carefully controlled brine test is sometimes used to judge shell thickness of eggs for hatching purposes but the test has no application to freshness of table eggs . How important is freshness ? As an egg ages , the white becomes thinner , the yolk becomes flatter and the yolk membrane becomes weaker . These changes do n't have any great effect on the nutritional quality of the egg or its functional cooking properties in recipes . Appearance may be affected though . When poached or fried , the fresher the egg , the more it will hold its shape rather than spread out in the pan . However , if you hard-boil eggs that are at least a week old , you 'll find them easier to peel than fresher eggs . The stronger the yolk membrane , the less likely the yolk will break inadvertently .