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19 October 2011

What happens when you . . .

Freeze an egg?
I have a friend who told me that she freezes egg yolks or whites if she has a recipe calling for one part of the egg and not the other, and later uses the frozen part for a different recipe that needs the other egg part. I've wondered for ages what would happen if an egg is frozen whole, and this weekend, I found out.

The shell cracked quite neatly, which is exactly what I was hoping for. Here's what it looked like an hour later:

Then I was able to pull the shell right off, leaving this:

After which I put it in the fridge to finish thawing. I ate it for breakfast, and it was edible, but didn't taste or act very fresh anymore. It spread out a lot instead of being thick and firm and didn't have much flavor. I forgot to take a picture of the cooked egg, being hungry at the time.

After the experiment, I thought to read up on the subject in On Food and Cooking: the Science and Lore of the Kitchen (2004). McGee on page 83 says: "Eggs can be stored frozen for several months in airtight containers. Remove them from the shell, which would shatter, as its contents expand during freezing." He also notes that the whites freeze better than the yolks or blended whole eggs, which become pasty  from protein aggregation and do not combine well with other ingredients without proper pretreatment by blending with salt, sugar or acid.  I did not notice pastiness in my egg, and I was still able to keep the yolk soft during cooking. Perhaps my egg was not frozen long enough to experience protein aggregation. What happened to my frozen egg sounds more like the deterioration that normally happens to eggs as they age, which McGee describes on page 81; the white was runny and the yolk membrane was delicate and very easily broken.

Here is one more thought from McGee: "Each [chicken] egg is about 3% of the hen's weight, so in a year of laying, she converts about eight times her body weight into eggs. A quarter of her daily energy expenditure goes toward egg-making; a duck puts in half"(page 73). It makes me think about the chicken named Speck that we had for a little while when I was about 12 years old. One she one day started disappearing for all but 20 minutes a day to come and eat. When we finally found where she was hiding, she had a nest and about 20 eggs that she was determined to hatch. We threw them out, since they would just rot, and she persisted in hiding and laying for several months. Isn't biology amazing?


  1. Poor Speck. You should have gotten her a rooster friend!

  2. First, I must say that only an evil person names her blog Gooey Somethings. Nothing good can come of our new relationship, Coralee. Between you and my sis-in-law, I'm going to weigh about 900 lbs by 2013.
    Second, this is fascinating. I've always wondered if eggs could be "food storaged" in the freezer. I mean, they might not taste or act fresh but can you still make them into cookies?
    Third, I read somewhere that if you rub them in mineral oil, the shells do better--or something along those lines. I read this from someone who freezes eggs as food storage. I'm too cheap and nervous to do it. But you were brave. Maybe I'll try it out.

  3. Jenna, you should check out this book from the library, it's really cool and has all sorts of science-y things, like how the egg proteins coagulate, how bread crust browns, lists of flavor and aroma chemicals, things like that. McGee also mentions the egg oiling as a way to slow down deterioration, but refrigeration works just as well. I don't know how it would work for keeping the shells intact or the overall quality better during freezing. After this experiment, I think I would only freeze eggs if, say, I made an angel food cake and had 12 leftover egg yolks and no idea what to do with them. And even then, there's no guarantee that I'll use them anytime in the future. But now I'm thinking about trying some powdered eggs, I wonder how well they work. Have you ever tried them?

    Josie, I did try to talk my mom into getting a rooster because it seemed so sad, but looking back, I don't think we could have handled bunches of chickens as well as the goats. :)

  4. I SHOULD check out that book. Sounds so interesting. I'm sure Isaac would love reading it with me (or ripping the pages out of it).

    We have powdered eggs in our food storage but since they come in mega quantities, we've never tried them. Our thinking is that if it's the end of the world, powdered anything will taste fine.