Chilling Thoughts

But as far as I can see, water cannot bring about toughness.

I feel that extra-large eggs are now barely big enough to qualify as large, and large eggs are barely big enough to qualify as small eggs. Are there any standards for eggs, and is it true that eggs are getting smaller?

Eggs come in many sizes, depending on the hen's age, breed and weight, and any stressful environmental factors such as heat, overcrowding and poor nutrition. I'm told that keeping one's chickens happy can pay off for the farmer in bigger eggs, which will sell at a higher price.

The U.S. Department of Agriculture places eggs in six categories, based on the net weight of an entire dozen. That's weight, not size. The designations and their minimum by-the-dozen weights are jumbo (30 ounces), extra large (27 ounces), large (24 ounces), medium (21 ounces), small (18 ounces) and peewee (15 ounces).

I have no evidence that hens are being raised today under more stressful conditions than in the halcyon days of small, local farms (although I'd be willing to believe that) or that the hens have therefore been laying smaller eggs. Even if that were true, the USDA's weight standards should control how they are labeled at the market. And while you're unlikely to discover a peewee stowaway in a carton of jumbos, remember that the eggs in a given dozen can vary somewhat in size, as long as they average out to the USDA's minimum weights.

Still suspicious? Weigh your eggs. If a carton of 12 large eggs weighs less than 24 ounces (don't forget to account for the weight of the carton), you're not getting what you paid for.

I spot-checked three brands of large eggs in my local market. Two cartons were labeled "net weight 24 ounces," and the eggs actually weighed 25.5 and 25 ounces. The third dozen, with no net weight statement on the carton, weighed 22.25 ounces, 7 percent less than required by law. Ironically, that carton was the only one to bear the USDA's official shield (USDA grading is optional with producers) and cost almost three times as much as the cheapest of the three.

So you may be right to question your egg sizes. Caveat emptor!

Robert L. Wolke (http://www.robertwolke.com) is professor emeritus of chemistry at the University of Pittsburgh. His latest book is "What Einstein Told His Cook 2, The Sequel: Further Adventures in Kitchen Science" (W.W. Norton, 2005). He can be reached atwolke@pitt.edu.