The White Lady - Part 1

Friends of ERRE4M, welcome to this new post. Today we are going to talk about meringue!
Having covered sponge cake as a whole, in this post too we turn to how the whipping power of eggs is put to use — in this case, more precisely, the extremely high whipping capacity of the egg white, or albumen. 
Before we get into the composition and the preparation methods of meringue, I would like to dwell on the main characteristics of the base ingredient of this dessert, namely the egg white.
The egg white is made up mainly of ovalbumin, a protein that is decisive for its whipping properties. 

TECHNICAL EXPLANATION ON OVALBUMIN
Ovalbumin is a glycoprotein, that is, a double molecule: one part is formed by a protein and the other by a sugar; this property makes it extremely good at binding and trapping air. This is one of the reasons why the egg white, once beaten, can increase its initial volume as much as fivefold. 
A second reason that gives the egg white its very high foaming power lies in its composition: it consists essentially of 86% water and 13% protein; the fact that it contains no fat inside (unlike whole eggs, and even more so egg yolks) allows the ovalbumins to bond together easily, thanks to the energy produced by the movement of the mixer. 

TECHNICAL EXPLANATION ON THE EGG WHITE
When the egg white is subjected to mechanical movement it absorbs air, dispersing a gaseous phase within a liquid phase and forming a genuine foam. In the egg white (which, as noted, is fat-free) the air easily interrupts the forces binding the surface molecules together, mingling intimately with them to form a foam that proves very stable. In the yolk and the whole egg, by contrast, the presence of fat means the surface forces cannot loosen, so that the air able to work its way in is smaller in quantity and, moreover, more easily dispersed. Hence the greater stability of whipped egg white compared with yolk or whole egg. 

The master's secrets

Now let us look at a few tricks that make the egg white foam more easily and better, and that apply to any foaming use of it.

ADDING ACIDS: citrus juice, white wine vinegar or cream of tartar, added in small amounts, increase the whipping power, because raising the pH of the egg white brings its proteins closer together and, as a result, lets it take in more air.

HEATING: about three minutes at 50 °C brings a marked improvement in both the whipping time and the volume. 

SALT: contrary to what is often said, salt in the egg white affects its whipping power only marginally; if anything, as whipping goes on it would tend to depress the protein functions. 

OIL AND FATS: as mentioned, the whipping power of the egg white drops sharply in the presence of, or with the addition of, oil or fats; even a small amount of oil in the egg white makes the foam collapse noticeably, so the presence of yolk in the egg white, or of fat on the equipment used, delays and slows the whipping power and, in significant amounts, inhibits it.

MILK AND DAIRY: adding milk fat, butter or cream strongly inhibits the stability of the egg white foam. 

WATER: adding water to the egg white increases its volume on the one hand, but on the other reduces its stability.

We also know that egg white foam keeps its aerated structure for a long time even when a certain quantity of heavier ingredients, such as sugars, is added. Sugars are, in fact, the ingredient commonly paired with egg white to form meringue, although — as we will see in later posts — other ingredients can be added to the whipped egg white and sugar to create “modified meringues”. 

White beet caster sugar is normally the most widely used, thanks to its characteristically fine grain, which dissolves easily in the egg white and lends stability to the mass; it must always be free of impurities and of any trace of other raw materials, so as not to weaken the egg white. Icing sugar can also be used, although it is generally blended with starches — which do not affect the whipping and, on the contrary, tend to keep the shape stable during baking.

Since meringue is made only with egg white and sugar, it is immediately clear that the variations in the ratios between the ingredients are very limited, whereas the working methods applied vary according to the final product we want to obtain. 

The ratio of egg white to sugar determines not so much the sweetness of the product as its texture, and meringue is usually divided into two mixtures: LIGHT and HEAVY. Light meringue normally has equal weights of egg white and sugar, while heavy meringue has twice as much sugar as egg white. (LIGHT MERINGUE 100 g egg white + 100 g sugar; HEAVY MERINGUE 100 g egg white + 200 g sugar).

In any case, it can be said that the two types of meringue — including all the possible intermediate variations in the ratio between the two ingredients — do not express any higher quality of one over the other:

LOW SUGAR = light meringue: firm, rigid, resilient and stable

HIGH SUGAR = heavy meringue: tender, soft texture, less solid.

There are many procedures for preparing meringue, but they are normally distinguished into three types: THE COLD METHOD, THE HOT METHOD and THE ITALIAN METHOD.

Let us now look at the first two, which concern baked meringue.

Cold method

COLD METHOD:    

100 g egg white at room temperature

100–200 g caster sugar

Flavouring to taste

METHOD:

• start by mixing the egg white by hand, in the bowl where you will whip the meringue, with about 1/3 of the sugar, so that the sugar begins to dissolve;

This does two things: the egg white will not be over-whipped — which avoids the classic lumpy structure that egg white takes on when it is over-beaten — and, by adding a solid (the sugar) to the egg white, you obtain a firmer, more rigid whipped mass with a greater volume during baking.

• once the egg white is well mixed with the first part of the sugar, start whipping everything at second speed and, when the whisk marks begin to appear on the foam, move up to third speed until you have a frothy, firm mass. At this point bring the mixer back to first speed, adding the second third of the sugar a little at a time;
• take the bowl off the stand mixer and add the last third of the sugar, folding gently by hand with the help of a spatula.
• to finish, you can add flavouring and colouring if you wish.

Hot method

HOT METHOD:     

100 g egg white at room temperature

100–200 g caster sugar

Flavouring to taste

METHOD:

• broadly speaking, proceed as for the cold method, except that the egg white must be heated to 50 °C in a bain-marie with half the sugar, holding that temperature for three minutes;
• whip everything at third speed until it cools;
• take the bowl off the stand mixer and fold in the second half of the sugar by hand with a spatula, adding flavouring and/or colouring at the end.
• once finished, the meringue is normally piped into a piping bag fitted with a plain or star nozzle and worked into the desired shapes on baking paper.

Baking

We wrap up this post on meringue by looking at how it is baked. Rather than true baking, with meringue we speak of drying; this stage is in fact carried out at low temperature and over a fairly long time. In large professional ovens, the temperature is set at around 90–110 °C for 2–3 hours, always with the steam-extraction system in the baking chamber switched on (the technical term is VALVE). The oven's low heat serves two purposes:

• the first is to allow the water in the egg white to evaporate slowly and the sugar to crystallise in a controlled way, which then permits a slight rise of the meringue and the creation of an extremely dry, crumbly, light product with a crystalline structure;
• the second is to keep the meringue from taking on too amber a colour, which would happen at temperatures above 120 °C; the low baking temperature, by contrast, lets the meringue keep the snow-white look it had after whipping, and therefore a very pleasing appearance too.

In home ovens I recommend keeping the baking time unchanged but lowering the temperature to around 50–60 °C, since the small size of the oven tends to build up more heat inside the baking chamber. Baking at 90–110 °C, we risk ending up with hazelnut-coloured meringues, which is not very satisfactory. To mimic the “VALVE” of professional ovens, it is enough to make a slit in the oven door with the blade of a knife, so that the steam produced during baking escapes from the oven and dries the product perfectly.

Good work!

(Blog by Enrico Gumirato, Pastry Chef and Trainer)