The Egg White Enigma

[vice]

I've been thinking about this for a while now. The conventional wisdom when creating an egg white foam is that not a drop of fat should come in contact with the whites, lest the fat prevent formation of a protein scaffold that traps air bubbles. Yet what of drinks like flips or the Ramos Fizz that combine egg white with fats (egg yolk and cream, respectively)? Now, the foam in these drinks could certainly be formed by the fats themselves. Cream, of course, foams quite nicely on its own. This warrants the question: what exactly is doing the foaming in drinks with both fats and proteins in the tin?

I see several follow-ups as potentially relevant:

• Will fats create stable foams in the presence of additional liquids, especially those containing alcohol? The foam coating my now-empty glass that contained a Carpano flip may be a sign pointing to yes.
  
• If the foam in a Ramos is fat-based, are there other textural qualities imparted by the egg white or is it superfluous?
  
• How are such cocktails reconciled with the established dogma that fats prevent proteins from foaming?
  

Thoughts?

[Chris Amirault]

I'm hoping that someone has an opinion about this. I'm confused, too.

[KatieLoeb]

If the foam in a Ramos is fat-based, are there other textural qualities imparted by the egg white or is it superfluous?

The egg whites for a Ramos are most definitely adding a meringue-like texture and lightness to the drink if they've been properly dry shaken first by themselves (preferably with the spring from a Hawthorne strainer in the shaker with them) and then had the rest of the ingredients incorporated.

My guess is that there's some cooking logic mixed in here with cocktail logic, which seem to be two quite different things. I think it's best to think about the end result for a drink that will sit on a bar for as long as it takes for someone to drink it, as opposed to the conventional wisdom of "thinking like a chef" and treating the egg whites as if they were going into angel food cake or meringue cookies. Meringue is a foam. The foam is a collection of proteins trapping tiny air bubbles. Getting even so much as a speck of egg yolk in with your whites when making meringue will keep the whites from achieving maximal volume. For cocktails, fresher eggs are better because stability is more important than volume in the final product. For cooking, maximal volume is preferred over stability so the thinner whites of several day old eggs are preferable. Cocktail bars tend to keep their eggs refrigerated and can't wait half an hour for the whites to come to room temperature while a customer is waiting for their drink. Colder whites don't whip up as high as room temperature whites. I believe both the practical aspects of using fresh eggs behind a bar as well as the purely mechanical aspects of making drinks containing egg whites are at issue here, as well as some plain old confusion.

Edited November 28, 2009 by KatieLoeb (log)

[slkinsey]

There is some question in my mind as to whether the foam on a Ramos Fizz is a protein stabilized foam (egg white) or a fat stabilized foam (cream). It can't really be both.

While it is true that a protein stabilized foam is inhibited by the presence of fat, it is not impossible to make one. Indeed, it is possible to make a dense foam using whole eggs if you beat it long enough, and we do get some foam on the top of whole egg cocktails. Protein stabilized foams are also enhanced by the presence of acid, which may help to counteract some of the inhibiting action of the fat. It is also true, as Katie points out, that the foam on the top of a cocktail is hardly the kind of persistent, high-volume foam they are expecting in a pastry kitchen.

On the other hand, perhaps the foam on a Ramos Fizz is really a fat stabilized foam. The foam on a Ramos Fizz seems to me to be more dense and creamy -- more like a fat stabilized foam -- than the foam on, say, a Pisco Sour. The way to find out would be to make three Ramos Fizzes; one with the standard recipe, one with cream only and one with egg white only. Take a look at the foam on all three and pick the two that are most similar.