When you ask Susan about her favorite food, she will quickly say that it is the humble fried egg, her staple lunch fare for decades. If she were stranded on a desert island (or in China) and could only have one thing to eat, this would be it:
You can select individual eggs in the market or choose them from bulk boxes at local stores. Some shops also sell eggs in clear plastic cartons, often containing quite a variety of egg sizes. For example, here are two eggs from the SAME carton:
When buying eggs, our biggest question has to do with freshness. Although the eggs in the carton contain a slip of paper with a packing date code, it is easily changed to fool customers. This question is compounded by the fact that eggs in China are not refrigerated.
After purchasing eggs, you can check their freshness by dropping them into a pan of water. If they sink and lie flat on the bottom, you’ve got some good eggs. If they stand on end, they’re getting old, and if they float to the top, toss them out (we once bought an entire carton of eggs that floated!).
Two months ago, we bought some particularly fresh eggs (shown here in a pot of water), each one tagged with a red sticker on the end:
This prompted Susan to run an experiment (she should’ve been a food science major), testing the benefits of egg refrigeration. Two eggs were kept in a kitchen cabinet and two in the refrigerator. After 9 days, all four eggs are still lying down and looking good (non-refrigerated on the left and refrigerated on the right):
After 16 days, only one egg (a refrigerated one) is still lying down:
After 22 days, all of the eggs are standing up:
30 days into the test, one of the non-refrigerated eggs floats to the top:
After 45 days, both non-refrigerated eggs are floating:
Two months later, the refrigerated eggs are still submerged while the others are floating high:
Based on this test, fresh eggs probably don’t need to be refrigerated if you consume them in the first couple of weeks. But since our eggs are rarely fresh, we’ll probably keep them in the refrigerator.
Such a “Robnett” experiment to do! I’ll be keeping my eggs in the refrigerator as well 😉
Wow — that’s great! Very cool experiment… (and over such a long time period, too). Seems like something that should be submitted to consumer reports.
This has gotten my curiosity so I did some googling. Lots of info on this topic. Based on my quick search your refrig eggs stayed fresher significantly longer (60 days) than I saw reported anywhere. The science is the shells are porous, the water evaporates and is replaced by air (and other decomp gas) resulting in increased buoyancy. I guess Chinese eggs are less porous than our eggs! My question is….did you eat the egg that was 2-months old??
We didn’t eat these particular eggs since we knew their actual age, but we’ve probably eaten older ones in ignorance (and they were probably cooked in gutter oil).