Why Poaching Fish is Better Than Boiling
What has less flavor than water? I pose the question to my cooking college class. Nothing! Nothing has less flavor than water. If you’re thinking about poaching fish, chicken, or eggs, why not ADD flavor to the final result by cooking them in a flavorful liquid?
That’s the first rule of cooking something in a poaching method. Don’t use flavorless water, always poach items in a flavorful liquid. Have you ever boiled carrots in water? The result is carrots that taste like water and water that is orange. Hmm, where did the flavor go?
You should never boil something in the kitchen anyway. In my opinion, boiling is NOT a cooking method. The relatively high temperature and violent motion of the liquid is a very bad way to treat your food.
To cook food in a moist convective manner, you must control the heat. Most people think that just because you’re cooking something in liquid, it’s always at a high heat rapid boil. When you cook something in the oven, is it always at the highest temperature? No. When you sauté, is the flame always on high? No, you control the heat.
There’s a big difference between boil, simmer, and poach. Water boils at 212F (100c) and is characterized by large, violent motion. A simmer is 185F (85c). You can always tell when your cooking liquid is simmering because there are soft bubbles around the rim of the pan and a slight convection or motion.
Poaching fish, or anything else, means having the liquid keep a constant 165F (74c) temperature. This is the perfect number for cooking something because proteins coagulate at the same temperature. This is the mile-marker that tells you when something is done cooking.
A correct poaching liquid has no visible bubbles and only a slight convection to the liquid. Little pieces of fat or crumb may lazily float by; moving slowly, but you shouldn’t see any bubbles. Why use a violent boil at 212F (100c) that will toughen and damage food when it’s possible to cook at precisely the right temperature you need, 165F (74c)?
The disadvantage to cooking something this way is the lack of eye-appeal. Since poached food is never cooked at a temperature above 165F (74c), it never reaches caramelization of sugars which occurs at 320F (160c). Caramelization is the brown color or grill marks that makes your cooked food look so appealing.
However, if the food item is to be used as a stuffing and cooked a second time, perhaps how it looks isn’t as important as how it tastes. We’re making Chicken Burritos in cooking college today. The chicken is poached, shredded, filled into tortilla and baked again. We’d gladly sacrifice eye-appeal of the chicken for flavor and moisture in this dish.
Poaching fish or delicate food like eggs is an especially good use of this technique because you can add flavor and moisture to an item that might dry out in other cooking processes. I’ve used shrimp flavored broths or juice and wine mixtures on tender fish filets to add a whole new flavor dimension.
When you can control moist heat in the way you do for dry heat, then you’ve developed a professional level skill. The difference between boil, simmer, and poach will help guide you toward moist and flavorful items that aren’t rubbery; but skillfully cooked and have much more flavor than water.
See Chef Todd’s live culinary class on poaching fish.