It's easy to think of the procedure for making stock as just another recipe. "Add this, this and this to the pot, simmer for this long and you're done." And it's certainly possible to prepare a decent stock using this approach.
But given the importance of stock and its relationship to so many other areas of the culinary arts, it's worth taking the time to understand the purpose of each ingredient, and the properties each one brings to the stock.
Bones for Making Stock
Bones contain collagen, which when simmered forms gelatin. The more gelatin there is in the stock, the more body it will have. When chilled, a good stock should actually solidify.
Types of bones that are naturally high in cartilage include:
- So-called "knuckle bones" found in the large joints
- Bones of younger animals, which is why veal bones are so desirable
White Stock Vs. Brown Stock
White stocks are used as the base for velouté sauce and various derivative sauces like the allemande and suprême sauces.
Brown stocks are used for making demi-glace and its derivatives, such as bordelaise and Robert.
Note that beef or veal bones can be used for either white or brown stocks. The difference is that when making white stock, the bones are blanched first, or quickly boiled, then drained and rinsed, before simmering.
For brown stock, the bones are roasted before simmering, and some sort of tomato product is usually added. The roasting and tomato product give the brown stock its darker color.
Use Cold Water for Making Stock
The reason we start with cold water is that certain proteins, notably albumin, will only dissolve in cold water. And albumin helps clarify a stock. Therefore, starting with cold water helps release the albumin, giving us a clearer stock.
And speaking of water, much of the process of making stock comes down to removing impurities. So it stands to reason that you'd want to start with the purest water you can get. For that reason, it's best to use filtered water whenever possible. If you don't have a home water filtration system, one of those activated charcoal pitchers will do the job nicely.
Mirepoix: Aromatic Vegetables for Stock
Mirepoix (pronounced "MEER-pwah") is a combination of chopped carrots, celery and onions used to add flavor and aroma to stocks. The usual proportions (by weight) for making mirepoix are:
- 50% onions
- 25% carrots
- 25% celery
For more about mirepoix, including how to cut it, how much of it you need for different kinds of stock, and some variations on the basic mirepoix described above, check out this detailed article all about mirepoix.
Acid Helps in Making Stock
Acid helps break down the cartilage and other connective tissues in the bones, thus accelerating the formation of gelatin. The acid products used are generally one or another of the following:
- Tomato: Brown stocks use some sort of tomato product, usually tomato paste, which also adds color and flavor to the stock.
- Wine: White stock and chicken stock sometimes use white wine, and fish stock almost always does.
One thing to remember is that acid reacts with aluminum cookware, so use a stainless steel stockpot for making stock.
Flavorings & Aromatics
Small amounts of herbs, spices and additional aromatics (above and beyond the mirepoix) can be added to stock, using one of two methods:
- sachet d'epices: a small cheesecloth sack of dried and fresh herbs and spices
- bouquet garni: a bundle of herbs and aromatics tied within sections of leek with cooking twine
Both the sachet and the bouquet garni are simmered in the stock at the end of a length of cooking twine which is itself tied to the handle of the stockpot, making it easy to retrieve.
Because stock is often further reduced — like when making demi-glace, for instance — salting the stock would make the resulting demi-glace much too salty. It's better to make a habit of seasoning your sauces just before service time rather than salting your stock.
Here's a tutorial showing you how to make brown stock, with photos illustrating each step.