Sauce for fruit, desserts, churning into icecream
Tools:
Mixer with wire whisk attachment
Candy Thermometer (with range room temp to at least 220)
Heavy Bottomed Saucepan
2 prep bowls for separating eggs
fine mesh wire sieve
Ingredients:
Sugar (2/3 cup, ??? g)
Egg Yolks (5, 88g)
Milk, half+half, or cream (2 cups) (heavier, more ice-creamy with higher fat content)
vanilla extract or other flavoring agent (chocolate, orange extract, almond extract, etc)
corn starch (optional)
salt (optional)
Steps:
0. Separate 5 eggs as per procedure (future blog post about separating eggs), placing yolks in mixer bowl, under wire whisk attachment.
1. Beat in 2/3 cup granulated sugar, adding gradually to avoid clumps and to allow the sugar to dissolve in the egg yolks. Add a pinch of salt. Continue beating for 2-3 minutes until mixture is pale yellow and forms a ribbon.
1 1/2. Optional. If not using a thermometer, add 1 tsp cornstarch to egg mixture.
2. Heat 2 cups milk or cream over high heat, watch and stir. The point here is just to get it hot to minimize the time you have to stir later. When the milk begins to foam, take it off. CAREFUL: milk can jump straight out of the pot the minute you turn your back on it.
3. Pour a small amount of the heated milk into the beating mixer, and wait until it is well incorporated. Then slowly pour the remaining milk into the mixer and whisk for about a minute, until thoroughly blended.
4. Return mixture to saucepan set over very low heat, insert thermometer such that tip is covered but does not touch the bottom. Stir constantly and watch the temperature.
5. When temperature hits 165F, remove from heat and continue stirring. Residual heat in the pan will bring the temperature the rest of the way to coagulation. Sauce should coat the back of a the stirring spoon, and a line drawn with your finger over the back of the spoon should remain visible. Continue to stir until the temperature peaks and begins to recede.
6. Add 1-2 tsp vanilla extract and stir until well incorporated.
7. Strain through a fine sieve to remove any curdled bits.
Notes:
a. Egg yolks are about 50% water, which should be enough to dissolve the sugar. The mixture lightens because of the incorporation of air as sugar raises the viscosity enough to retain bubbles. Granulated sugar (as opposed to powdered sugar) is convenient for mixing air into the yolks, although I'm not sure if that's actually important.
b. Dissolved sugar and milk present around egg proteins raises their coagulation temperature from ~160 F to ~170-180F. Exceeding the coagulation temperature by 5-10F begins to break down the protein structure, producing grainy curds.
c. Heating slowly gives more margin of error for checking the temperature and the state of coagulation
d. Adding hot milk to cold eggs helps bring their temperature up slowly, and prevents them from overshooting their intended temperature and curdling
e. It isn't absolutely necessary to pre-heat the cream at all, but its faster, because it doesnt have to be done all at the end, slowly. Back in the day, scalding the milk killed enzymes which can keep the sauce from thickening, but the pasteurization has already done this for us. I suppose raw milk should be scalded.
f. Starch added to the mixture gelatinizes at ~175F, releasing its own long-chain starch molecules, absorbing energy and interfering with the egg proteins attempts to bind to each other. Chocolate and cocoa can also fill this role. Starch does tend to thicken the sauce, and make it less smooth and flavorful
g. A pinch of salt added to the mixture provides ions to surround charged ends of egg protein molecules, allowing them to extend near each other and bond, creating a more coherent gel. Not sure if this function is also provided by the sugar, or by elements of the milk. Probably adds to the flavor a little.
h. Original Creme Anglaise (or creme brulee) Recipe: F. Massialot, 16.92
i. Adding starch to the mixture prevents egg proteins from binding to each other by releasing its own long starch molecules at about the same temperature that
j. Sprinking sugar over the top surface of the finished cream inhibits evaporation, and prevents a leathery skin from forming on the surface.
k. The number of yolks can be increased considerably, resulting in a thicker sauce
l. An ice-water bath can be used to rapidly cool the creme, with continuous stirring to prevent solidification.
m. When milk is heated to 160F, whey proteins begin to unfold and create a briefly stable foam. The foam could also be abetted by a layer of cream on the top surface, with steam forming just below, as a source for the bubbles. Don't have a great explanation yet.
References:
Mastering the art of French Cooking, pg 588
Joy of Cooking, Pg 771 and 735
On Food and Cooking, Pg. 92-94
http://www.joyofbaking.com/CremeAnglaise.html
