To poach something means to cook it by submerging it in a liquid. Poaching liquid can be water, stock, milk, or even wine.
What makes poaching different from other “moist heat” cooking techniques like boiling and simmering, has to do with the temperature at which the food is cooked. Poaching is done at a relatively low temperature, usually around 160-180 °F (71-82° C)
It can also be a very healthy method for cooking because it usually doesn’t require any fat to cook the food. There can be exceptions to this however.
Poaching can be done with any flavorful liquid, but the traditional liquid used was a court bouillon made from an acid such as lemon juice or wine, along with some aromatics.
What makes it different from other methods, is that it’s primarily used for preparing delicate foods such as eggs or fruit.
Simmering is done at a temperature that is right below the boiling point of water. Although it’s great for cooking foods very evenly, poaching is still the ideal method for delicate food items.
Boiling uses the highest water temperature possible to cook food, and is by far the least likely method to be used when cooking delicate foods.
Poaching allows the proteins in the food to denature without taking too much moisture from the food. That’s why it’s important to keep the heat low as well as keeping the cooking time to a minimum, to preserve as much flavor as possible.
There are a couple variations to poaching.
One is called shallow poaching which uses a shallow cooking pan, and is great for cooking naturally tender, smaller sized pieces of meats, and fish. I mentioned earlier that this method of cooking is generally considered a very healthy way to cook food, but sometimes it’s not.
When shallow poaching, butter can be placed in the pan and certain aromatics can then be added. Food items are then placed on top of the aromatics, and cold liquid is added until the food is partially submerged. The liquid can then be heated, which in turn heats the food. The liquid should be heated until close to boiling but never allowed to reach that point.
The next method is called deep poaching. This technique requires a larger cooking vessel with sufficient space to fully hold the food, poaching liquid, and any aromatics comfortably. There should also be enough room to spare so that the liquid can expand without overflowing, and the surface should be able to be skimmed off if needed.
I prefer deep poaching when cooking eggs for eggs Benedict. Since egg whites are mostly protein and protein begins to coagulate or set when it comes in contact with heat, I prefer to use a little vinegar when I poach my eggs.
This causes the whites to firm up faster and prevents them from breaking up and dispersing throughout the water.