Poaching Poaching is cooking by immersing in simmering liquid. It works particularly well with chicken and fish. Place a single layer of the chicken or fish in a shallow, wide pan and barely cover with liquid. You can use water, water seasoned with spices and herbs, low-fat milk, broth or a mixture of white wine and water. After cooking, you can cook the liquid to reduce it, then thicken it to make a sauce.