Food Science Question - Eggs

Mary Sara said:

I don't know if anyone here would know this kind of thing, but thought
I'd ask anyway....

I have 2 baked custard recipes (actually Pots de Creme au Chocolat).

One calls for whisking the egg yolks and sugar to a "lazy ribbon" then
combining with the cream/chocolate/vanilla mixture and bake.

The other says to stir the egg yolks to mix lightly, then combine with
the cream/chocolate/sugar/vanilla mixture, then put it all in a double
boiler and stir them over low heat for about 3 minutes.

This recipe is then poured into cups and baked also?

Quoted message said:

My question is this: after baking and cooling, how would the custards be
different? Would the textures be different, and if so, how? Would one be
thinner than the other? Smoother? Creamier? Richer?

Same number of eggs for either recipe?

Quoted message said:

Would those made with the partially-cooked mixture bake faster than
those made with the whisked yolks?

Probably. What do the directions say?

Quoted message said:

What difference, if any, does the air incorporated into the whisked
yolks make?

Or is the purpose of both just to thicken the egg yolks, and they would
turn out the same? Does whisking egg yolks with sugar have the same
effect on the proteins in the yolks as gentle heating would?

Are there any food scientists here who know this kind of thing?

There are two basic types of custard- stirred custard and baked
custard. The stirred custard is generally looser and often pourable;
the baked custard is more of a gel. Your second recipe seems to be a
hybrid. If you're baking both of them and they have the same ratio of
eggs to other ingredients, then my guess is that pre-cooking the eggs
a bit while stirring will result in a softer custard because part of
the protein will denature before pouring and baking, resulting in a
less organized final structure, thus softer but perhaps not as silky.

I could be wrong :>

It's an interesting question. You could be a food scientist too, if
you try it both ways and let us know what happens!

Sue(tm)
Lead me not into temptation... I can find it myself!

Mary Sara said:

I don't know if anyone here would know this kind of thing, but thought
I'd ask anyway....

I have 2 baked custard recipes (actually Pots de Creme au Chocolat).

One calls for whisking the egg yolks and sugar to a "lazy ribbon" then
combining with the cream/chocolate/vanilla mixture and bake.

The other says to stir the egg yolks to mix lightly, then combine with
the cream/chocolate/sugar/vanilla mixture, then put it all in a double
boiler and stir them over low heat for about 3 minutes.

This is usually called "tempering" the mixture if it's later to be
baked. If it's to be completed stovetop, the finished product is called
a "stirred cream." For tempering, the premise is that the finished
temperature of the mix needs to be between about 180°F to set and this
is a gentle head start and insures that all solutions are made.

This is also the traditional way to make both creme brulee and pots de
creme until the 20th century. They were both made in a double boiler and
poured into cups and chilled. No baking at all.

Custards should be heated gently for optimum texture. That's why water
baths for most of them. It's good to keep the bottoms of the cups up off
the pan bottom, but I don't recommend a towel (it's fairly common
instruction) because the water can boil under it and jiggle the cups
around. Use a cake rack.

Quoted message said:

My question is this: after baking and cooling, how would the custards be
different? Would the textures be different, and if so, how? Would one be
thinner than the other? Smoother? Creamier? Richer?

The ribbon recipe is designed to accomplish several things. It insures
that the yolks and white that remains connected to it will be thoroughly
mixed. It insures that the water in the yolk is bound by the sugar. It
insures that a good percent of the sugar is already dissolved before
adding the other ingredients. But the other reality is that it doesn't
need to be whisked to a ribbon. Just make sure it's mixed thoroughly and
don't worry about the ribboning.

Quoted message said:

Would those made with the partially-cooked mixture bake faster than
those made with the whisked yolks?

Yes. The first one will likely take from a minimum of 40 minutes to near
an hour (assuming a water bath); the second more like 35 to 45 minutes.

Quoted message said:

What difference, if any, does the air incorporated into the whisked
yolks make?

Not much air will actually stay in the mixture. While there will be some
increase in volume, the point of whisking is to dissolve and distribute
the sugar fully. The whitening of the mixture as its being whisked means
that air is being incorporated. But as the other ingredients are added,
it deflates.

Quoted message said:

Or is the purpose of both just to thicken the egg yolks, and they would
turn out the same? Does whisking egg yolks with sugar have the same
effect on the proteins in the yolks as gentle heating would?

They will turn out very similarly. The sugar interferes with the
formation of a protein matrix offering a bit more leeway in the cooking.
The finished temperature will need to be between about 165°F and 185°F,
depending on what else is in there and what the proportions are. The
sugar makes the egg more forgiving and helps to minimize the bad things
that happen to custards (tunneling, curdling, etc.).

Happy pots de creme...

Pastorio