Eggs are one of the most magnificent ingredients known to man or woman. Where there is a kitchen, there is an egg close by. Eggs are used for both sweet and savoury dishes, and are eaten either by themselves, or as a key part of thousands of other dishes.
I cannot imagine a life without eggs, can you?
Although we mostly consume and use chicken eggs, the eggs of just about any bird – duck, ostrich, goose, quail, penguin, guinea fowl, partridge etc. – have found their way into home and commercial kitchens onto our plates in one form or another. Not surprising for an ingredient that is nearly as old as humankind itself.
But it is not the taste of the humble egg that accounts for much of its culinary use. Nope. It is their molecular properties, and to get a better understanding of just how these contribute to better food and cooking, we have to break an egg – quite literally.
The protective shell around chicken (and other bird) eggs consists of 95% calcium carbonate (held together by a bonding protein), which, not only protects the inner contents, but also prevents microbial infections and desiccation. Although we normally just crack the shell to get to the insides, one can also peel an egg chemically by using acetic acid known to cooks as vinegar. Just submerge an egg or two in a container with vinegar and watch them bubble. After about three days you’ll be rewarded with a perfectly shelled raw egg. Right now I have a few of these in my refrigerator packed in miso to ferment the yolks.
Next time you bake an egg, take a closer look. First, on the outer edges furthest away from the yolk in the center, there is a watery white part that congeals almost immediately into a solid white mass when the egg hits the hot pan. Second, right around the yolk, there is a thick circle of egg white that stays fluid, almost jell-like, for much longer. Thus, by the time the edges of the egg white is already over-cooked and crispy, the center is still quite jelly-like.
An egg, you will now discover, does not cook uniformly, and the different proteins that make up the egg (and there are around 40 of them), congeal at different temperatures. The parts that contain ovotransferin (also called, conalbumin) congeal at 63˚C, whereas the parts rich in ovalbumin, congeal at 80˚C. Egg yolks (containing lipoproteins) start to jellify at around 63˚C and is fully set at 70˚C. Next time someone asks you: “how would you like your fried?” think of the mammoth task ahead.
Another characteristic of the humble egg that account for its magic is the fact that it can be separated (yolk from white) and that the separate parts could be employed independent from each other to achieve different objectives. By separating the yolk from the white, we effectively remove the fat from the protein. Although there are many ways to do this, the objective is always the same: we want to whip the fat-free, protein-rich whites into a stiff foam, be it for a soufflé, a cake, a mousse, a meringue or a tart-filling. Whisking egg whites introduces air into the mix where it is trapped by the proteins in the whites, creating relatively stable foam. This is then used to aerate the final dish (i.e. make it rise when baked and giving it a light and fluffy texture). For egg whites to form a foam, they have to be completely devoid of any fat. Thus, take great care in separating eggs, for any amount of yolk in your egg whites, will prevent them from rising when whipped.
The yolks on the other hand, are used to create emulsions. An emulsion is created when two immiscible fluids (such as oil and vinegar) are brought together (as in mayonnaise) by a third agent, the emulsifier (such as the lecithen in egg yolks).
Most people I know like meringues, but hardly ever try to make it at home. The first reference in a cookbook to meringues date back to 1692, but it is commonly believed that its origins date much further back. At its core, the meringue is egg whites beaten to a stiff foam and sweetened by sugar. There are three methods by which to make a meringue:
- French meringue that is made by beating fine white sugar into egg whites. The foam is then shaped and baked in an oven.
- Italian meringue is made by first whipping the egg whites into a soft foam after which a hot sugar syrup is slowly added whilst the whipping continues and the final foam is stiff and glossy. The hot syrup cooks the meringue and there is thus no need to bake it.
- Swiss meringue is made by first whipping the egg whites over a warm water-bath to heat them, then whipping continues as they cool down. Further cooking is also required for Swiss meringues.
Unfortunately sugar cannot be substituted in the making of a meringue, it is part of the structure of the dish. When the sugar is not dissolved completely, the meringue will “weep” or “sweat” (i.e. dispel moisture). Keeping meringues in environments of high humidity or adding them to fillings with high moisture content will have the same effect. To prevent the meringue topping from sliding off its tart base after cooking, the meringue should be anchored onto the crust.
This week’s recipe involves eggs – both as a foam and as an emulsion. I had some maguni juice left in the fridge and I wanted to experiment using them to make a curd. Just like you would make a classic lemon curd, but with maguni juice and a little less sugar. I used this as filling for my maguni-meringue tartlets.
If the poor maguni has something that counts against it, it is the colour. Try as I may, I can’t get the off-brown juice to look more appealing. But what the hell, the taste makes up for it, many times over. With a crust that incorporates fruity olive oil and a glossy Italian meringue topping, this might be the best thing I have cooked this month.