Baking – Does Sugar Cook Eggs

Yes!

Sugar is often used as a "wet" ingredient in baking. That means it needs to be dissolved in the water in order to prevent too much gluten from being produced (making the result fluffy/flaky, and not chewy). Different sugars hold different amounts of moisture (for example, brown sugar holds more than white) and using sugar with crystals that are too large (or too small) will make the texture come out completely wrong. Too small and your cake will be rubber; too large and your biscuit will fall apart.

Also, if you're using the sugar for creaming (with fat), you generally need to use a coarser sugar. Superfine sugar will dissolve too quickly and won't allow enough air to be incorporated. Confectioner's sugar is good for creaming but has completely different properties from crystal sugar - it's been "processed" and has cornstarch added, so you can't just substitute in equal quantities.

Of course, it goes without saying that the taste is different as well. But even more important than the taste are the solubility characteristics which, as explained above, will have noticeable effects on other parts of the recipe.

It does depend what you're baking; if the sugar is being used purely for flavouring, then you can use whatever sugar you like. Much of the time in baking though, sugar is used for more than just sweetening, and it's important to be aware of that. If the sugar is being creamed or dissolved, don't substitute unless you're sure you know what you're doing.

Technically, the minimum ratio of sugar is zero. You can definitely create a stable meringue without any sugar at all, although you'll have to mind your conditions and preparation - use a spotlessly-clean bowl, room-temperature egg whites (separated when chilled), initially foamed up on low speed with an acid such as vinegar or cream of tartar, superfine sugar (if you're using any at all) added very slowly after the soft peak stage, and a starch (e.g. corn starch or icing sugar) at the end for added stability.

The main problem, of course, is that as you allude to, when you bake it you'll basically end up with dried-out egg. It won't have any flavour at all. If you're just reducing the sugar then maybe this isn't a problem. If you're trying to eliminate the sugar entirely or almost entirely then you need to replace it with something - generally, a savory bomb, like very old cheese (for example Reggiano and chives), or very dark chocolate if it must be a dessert.

To do that, just grate or finely chop the strong/savory elements, whip the eggs up to the shiny peak stage, and fold in the shavings at the very end. The meringue will hold up.

But again, and I'm going to repeat myself here - you don't need a lot of sugar for stability. You can easily halve the sugar measurement for a traditional meringue recipe and still have it come out OK (albeit less tasty) - especially if you make one of the more stable meringue types, such as an Italian meringue where the sugar is combined as boiling sugar syrup. But you don't have to do that; simply reducing the sugar is fine if you're careful.