A chinois is a cone-shaped sieve, or strainer, and is a handy kitchen utensil to have for giving sauces and soups a smooth finish as well as for other tasks such as sifting powdered sugar onto baked goods.
The cone-shaped strainer part of a chinois is made of fine mesh. A good quality chinois is not cheap, but should last a long time unless the mesh strainer becomes punctured. It is a good idea to look for a chinois that has two loops of wire that stick out over the mesh part to help protect it.
The handle of a chinois may be made of plastic or stainless steel. Some styles of a chinois have two hooks that help hold it onto the top of your cooking pot. These double hooks can steady a chinois that is full of food to prevent it from tipping and spilling.
Some varieties of chinois have a cone-shaped wooden stick with them for helping to direct foods into the mesh strainer. You can also use a wooden spoon or a rubber spatula, but anything sharp that could damage the mesh should be avoided. In a pinch, a cheesecloth-lined regular coarse strainer can be used to substitute for a chinois, but most cooks prefer the real thing.
A chinois can be used for taking lumps out of gravy or even for taking the juice from citrus fruit. However, the most common use for a chinois is for making soup stock or sauces. For example, a chinois can be used to remove the seeds from tomatoes to prepare tomato sauce.
Some people use a chinois to prepare apple sauce. It is also known as a bouillon strainer and it is commonly used for preparing soup stock as the conical shape helps funnel the stock into your pot. The fine mesh also keeps the bigger pieces of meat from the bones from going into the soup stock and clouding the clear broth.