Mirepoix (pronounced "meer-pwah") is a combination of chopped carrots, celery and onions used to add flavor and aroma to stocks, sauces, soups and other foods. The proportions (by weight) for making mirepoix are 50% onions, 25% carrots and 25% celery.
[Also see: How to Make Chicken Stock]
When you're making stock, the mirepoix is ultimately strained out, so it's not important to use great precision when chopping the vegetables. The sizes should be more or less uniform, however, to allow for uniform cooking times.
The more finely mirepoix is chopped, the more quickly its flavor and aroma is released into a stock. Since brown stock is simmered longer than white stock, it's perfectly acceptable to cut the mirepoix into pieces an inch or two in size. For white stock, a ½-inch dice is probably best.
Making Stock with Mirepoix
For brown stocks such as beef stock, use a pound of mirepoix per 6 quarts of cold water. It's customary to roast the mirepoix before adding it to the stock liquid, which contributes flavor and color to the finished stock.
For white stocks such as chicken stock or veal stock, use about a pound of mirepoix for 5 quarts of cold water. For fish stock, use half a pound of mirepoix per gallon of cold water. You can cook the mirepoix and fish bones in butter for a few minutes before adding the water.
- Leeks can be used in place of some or all of the onions.
- If you want a colorless stock, you can make a "white mirepoix" by substituting parsnips, mushroom trimmings, or both, for the carrots, or just omitting the carrots altogether.