Q: Recently you posted a good refresher on how to cook hard boiled eggs. I was wondering if there is any way to tell the age of the eggs from the packaging? I know from your post I'm not supposed to buy fresh fresh eggs.
A: Good question!
Egg cartons these days only come with 2 bits of information on them - a bunch of codes, and an expiration date. There are two answers to your question, and both will work just fine.
The first and probably easiest answer is to look on the packaging for the expiration date, and choose a carton of eggs that will still be within the date 1-2 weeks from the date of purchase.
An expiration date on the carton is not required but, if one is used, it can be no more than 30 days after the eggs were packed. Remember, older eggs are easier to peel eggs.
The second potential answer involves a little bit of sleuthing, and looking like a smartypants..
Most cartons show a Julian date on the short side of the carton. The Julian date on the carton is the day the eggs were packed -- starting with 001 as Jan 1 and ending with 365 for December 31. For example, eggs packed on June 15 would be marked 166.
The eggs in the photo above were packed on August 9th - Julian calendar day 221, and have a sell by date of September 6 ( less than 30 days from pack date )
If you like knowing such stuff, here's a link to a PDF that has the Julian dates on it: http://www.imap.mesacounty.us/GPS_Survey/RINEX%20TIME/julian-calendar.pdf
Thanks for the question! I know you'll be much happier with your boiled egg final product once you begin using older eggs in the first place!