My Recipe Box
Food Science

Cooking Eggs with Sugar Alone

By Brian Geiger, contributor

May 7th, 2009

Kitchen Mysteries is a weekly exploration of oddities surrounding cooking and food. They could be recipes that fail when they shouldn't, conflicting advice from different sources, or just plain weirdness. If it happens in a kitchen, and you're not sure why, send a tweet to The Food Geek to find out what's happening.

Rob asks via the feedback form on my web site:

I just read your post on how sugar and water are BFFs, but here's something that's been on my mind lately - some cooks tell you that when you combine sugar and eggs, you shouldn't leave it alone too long, or the sugar  will "cook" the eggs.

This makes even less sense to me than how sugar keeps water, water. Can you elaborate in a later post?


Hi, Rob,

Most of the time when we talk about cooking food, we are suggesting the use of heat to make radical changes in the chemical structure of the food. One of those changes is to denature proteins, or to take them from their natural state to some sort of new form.

An example of denaturing protein without heat is applying an acid to fish or poultry, which will cause the protein to turn from the somewhat translucent color it started with to the same sort of color it would had you cooked it, though without any browning from the Maillard reactions.

So let's talk eggs. In particular, I'm going to talk egg yolk, because I most frequently mix sugar with just the yolk when I'm making a custard. In an egg yolk, you have a lot of proteins floating around in a big pool of water. And some other things, but water is the important bit right now. The proteins are folded up right now, because that's how they normally are, and it gives them room to float without bumping into other proteins. If they bump into other proteins, they would join together, which ruins the relaxed nature of the swim.

When you cook an egg, you cause the proteins to stretch out so that they're much longer than they were when they were folded over. This means they take up a lot more space in the swimming pool, which causes them to bump into other proteins and link up.

Paula I. Figoni writes about what happens when sugar is left in the yolk in How Baking Works. Essentially, the sugar and the water get together, as they are known to do. They gossip about the moral implications of emulsions and the exciting lives of amino acids and whatever else young molecules like to gossip about.

The more water that gets tied up with the sugar, though, the smaller the swimming pool for the protein becomes. After a while, they don't even have to stretch out to bump into each other, it just happens. Because the protein is still folded, instead of making a nice regular mesh that normally happens with a cooked egg, you just get a hard clump of eggy protein. The last thing you want, especially with a custard, is a hard clump of eggy protein.

Hence, don't wait around once you've poured the sugar into the yolk. It's an easy way to ensure that whatever custard you're making will be smooth and tasty.

posted in: Blogs, food geek, water, egg, sugar, protein, yolk, denature, gossip, clump
Comments (8)

missmarinaa writes: When you cook eggs with sugar, does that also "cook" out salmonella, or does that concern have to be dealt with by heating the eggs to a certain degree? Posted: 10:09 am on December 22nd

TheFoodGeek writes: Any type of sugar should cause that effect, though I suspect that the finer the sugar, the faster the coagulation, because the fine sugar will dissolve more easily in the water. Posted: 5:26 pm on February 12th

0524 writes: My question on this is subject is, does it matter what type of sugar you are using to "cook" the eggs. i.e. should you only use 'table' sugar, or can you use confectioner's, superfine etc.. to cause the same effect? Posted: 2:09 pm on February 8th

nancecook writes: Yes, to find a recipe, I Googled lemon pots de creme and among many sites, went to the one from the Boston Globe (I'll paste the recipe below). Since writing you yesterday, I talked to a chef friend and her guess (after looking at the recipe) was that the recipe used too few egg yolks. The Boston Globe recipe only used 4 egg yolks. She said her recipe calls for 8 yolks. Since it is mostly the egg yolks that bind the custard, I suspect this might have been the problem. What do you think?

Lemon pots de creme
By Tony Rosenfeld, Globe Correspondent  |  December 31, 2008
Serves 6
Make these little lemon-infused creamy custards early in the day so they have time to set in the refrigerator.

1/2 cup sugar
4 egg yolks
Grated rind of 1 lemon
1/4 cup lemon juice
1-3/4 cups heavy cream
3/4 cup whole milk
12 thin strips lemon rind or 6 fresh mint leaves (for garnish)
1. Set the oven at 325 degrees. Bring a tea kettle of water to a boil. Set six ramekins or custard cups ( 1/2-cup capacity each) in a 9-by-13-inch baking dish.
2. In a large bowl, whisk the sugar, yolks, lemon rind, and juice. Whisk in the cream and milk until the sugar dissolves.
3. Transfer the mixture to a large glass measuring cup or pitcher. Divide it among the ramekins. Pour the hot water into the baking dish at the edges so it comes about 2/3 of the way up the sides of the ramekins. Set a piece of aluminum foil loosely over the baking dish (do not seal the edges).
4. Bake the custards for 45 minutes or until they jiggle only lightly. Begin checking after 30 minutes; check every 5 minutes.
5. Transfer the custards to a large rack to cool to room temperature. Cover with plastic wrap and refrigerate until cold. Garnish each with two strips of lemon rind or a fresh mint leaf. Tony Rosenfeld 
Posted: 1:30 pm on July 16th

TheFoodGeek writes: By chance, is the recipe for the lemon pots de creme available online for me to peruse? Posted: 11:12 pm on July 15th

nancecook writes: This is the only blog I found to try to figure out why my first attempt at making lemon pots de creme this a.m. failed miserably. I did everything as indicated in the recipe. Placed my filled custard cups (surrounded by hot water) in the 325 degree oven. Started checking them at 30 minutes, trying to determine when the custard was barely jiggling. Checked every 5 minutes until total baking time of 45 minutes had elapsed. Still seemed to be jiggling a tad too much but took them out of the oven anyway. The custard was still totally liquefied with no sign that further baking would produce a different result other than evaporation!! Where might I have gone wrong. I am not a novice cook and am purely disgusted! Posted: 3:12 pm on July 15th

TheFoodGeek writes: I don't recommend this path. There are two general reasons to cook something: to enhance the flavor/texture, or to make it safer to eat. The sugar definitely isn't going to get rid of any pathogens in the egg, and I haven't noticed any improvement in texture or flavor from letting the sugar sit. The best course it to whip the sugar into the yolk, mix that into the cream, and enjoy yourself some custard.

Of course, someone more into the cutting-edge of food techniques may be able to come up with something that will work from that, but I haven't found any evidence of it yet. Posted: 11:03 pm on May 17th

smiles562 writes: I have a question for you about this. Let's say you wanted to cook eggs with sugar to make some sort of breakfast without involving heat. Would you mix it together fast to create the custard you were talking about, or would you let it sit and get "hard clumps" of egg yolk that you could ultimately eat?

I'm not sure why this occurred to me, but in the case that I have eggs and sugar and have no heat (whether the electricity bill couldn't be paid or you are at a hotel where there's no where to cook but you have a mini refrigerator) and therefore would need to use another method. Posted: 8:01 am on May 9th

Log in or create a free account to post a comment.
Make it Tonight

Cookbooks, DVDs & More