Whipping Eggs

[miladyinsanity]

I've a recipe for a French Sponge Cake.

It calls for the eggs to be separated.

Then the egg whites are whipped with some of the sugar to stiff peaks, and the egg yolks whipped until pale and creamy with the remaining sugar.

After this, you fold the two together, then fold in the flour and melted butter.

Sounds like a genoise?

Well, it sounded like one to me, so I used the proportions given and made a genoise. IOW, instead of whipping the yolks and whites separately, I whipped the eggs to triple volume with the sugar, then folded in the flour and melted butter. And made my first successful genoise, I might add.

The question is: Would there be a difference between simply whipping whole eggs to triple volume and whipping the yolks and whites separately before folding them together?

If I have to, I'll give it a try this weekend, but I was thinking that somebody here would probably know.

[Franci]

For the genoise the eggs are warmed up and whipped in a bain marie.

I always do my sponge cake with whole eggs but in Italian is called pan di spagna

[miladyinsanity]

You don't have to warm the eggs to whip to triple volume if you have a mixer.

You warm the eggs to relax the proteins (correct me if I'm wrong) so that it's easier to whip, that's all.

[Franci]

I went back to my notes from school, just to refresh my memory

Whole eggs is considered a genoise, yes. Biscuit instead requires separated yolks and whites. They can be both considered sponge cakes. I read that if you bring the egg to 115 F/46 C, the gentle heating partially coagulates the protein and make them more elastic (so they can contain more air). The eggs should not be heated more than 120-125F

But I am sure there are people here that know more than me about this.

[chiantiglace]

You are right franci, heating the eggs will allow the eggs to whip higher/greater, not so much as faster.

The reason for seperating the eggs is because a seperate foaming method is by far more stable than any other foaming method. Allowing each individual component do their thing results in a stronger finish.

It is important that the yolks be whipped before the whites because whites start to lose volume immediately following the aeration.

Both components whip to different heights with different characteristics. The fat in the yolks inhibits whites ability to whip to their fullest, while the lecithin in the yolks allow the yolks to stay aerating much longer than the whites(reason why whipping them first).

Also, if you are keeping the eggs together while whipping it is quite necessary to do a warm foaming method, for best results that is.

edited to add: You dont necessarily heat them just to relax proteins, you could do that simply by adding some acid.

Edited September 29, 2006 by chiantiglace (log)

[reenicake]

Whole-egg foams and separated-egg foams differ when baked -- a genoise has a larger, more porous crumb and is usually delicate, but okay to be split in 3 layers, or baked high and fast to roll with a moist filling. Biscuit or pan de spagna is sturdier and more flexible, which means that they can be split thinner; or baked in sheets to wrap around charlottes; or rolled tightly and sliced to line a bowl; or piped as a finger (biscuit ala cuilliere)...

You usually want to do a separated-egg foam if there is more in there, such as nuts or a different flour like semolina; or more fat like a chiffon.

[miladyinsanity]

Aha!

I shall experiment this weekend. Thank you all!