The French sauces featured in "Mother Sauce" (December 2008, Issue 116) all begin as a meat stock; one of the keys to ensuring that you end up with a refined, velvety sauce is the careful and continuous skimming away of the fat and impurities that rise to the top of the pot as your stock simmers. Different sauciers have different methods for skimming, but all of them have the same goal: to remove as much of the unwanted foam as possible without removing the pure meat stock along with it. Here are four tried-and-true techniques we've come to rely on in the saveur test kitchen.
1. The cold-spoon method: Dip a large metal spoon in ice water and run the bottom of the spoon along the surface of the stock. The cold metal will cause fats in the foam to coagulate and stick to the bottom of the spoon.
2. The spin method: Dip the bottom of a long-handled ladle into the stock and begin swirling it in a circular motion, working from the center outward, until the foam accumulates around the edge of the pot, at which point it can be easily spooned away.
3. The convection method: Move the stockpot partially off the burner (using an overturned plate or a pie dish to prop up the overhanging section of the pot) so that only one side of the stock continues to simmer actively. The foam will accumulate toward the calm side of the pot, becoming easier to remove.
4. The big-skimmer method: Students at the École Supérieure de Cuisine Française in Paris use a wide, shallow perforated skimming tool, which, when wielded deftly, captures the fatty foam while allowing the pure stock to drain back into the pot.