There is no substitution for real stock. Luckily it is easy to make when you are eating mostly whole and fresh food and it's a great for the frugal chef. The hardest thing about making stock is finding the time to let it simmer on the stove. It takes about five hours start to finish. It's definitely worth the time. Stock will not only add incredible flavor to your food but it is very nourishing. Diane over at Spain in Iowa did a very detailed report on the health benefits of homemade stock.
If I ever get a deep freeze I would love to make a big old vat of stock and keep it frozen on hand. I know it is also possible to can stock. I may look into this more once we have our own place. For right now I just make one big pot worth at a time.
If you eat rotisserie chicken or anything that still has the bones save the bones and freeze them until you have enough to make stock.
I haven't been buying meat - it's too expensive for our budget. I insist we only buy local chicken, which is about twice as expensive as the Concentrated Animal Feeding Operations (CAFOs) chicken you will find sold in the average grocery.
But I did find I can buy very inexpensive chicken carcass which is sold as Chicken Soup Bones. For about $3 I get 2 pounds of bones (two chicken's worth of bones, necks included). Here's the recipe I use to make stock:
Homemade Chicken Stock
2 pounds chicken bones
1 yellow onion, quartered
2 carrots, chopped
5 cloves garlic
3 bay leaves
1 tablespoon dried thyme
1 tablespoon dried rosemary
1 tablespoon white or apple cidar vinegar
Step 1: In a 5 quart pot add all the ingredients then fill the pot with water about an inch from the top.
Step 2: Bring the pot to a boil and then cover and reduce to a simmer. Allow the pot to simmer for 2-3 hours.
Step 3: Strain out the bones and bits. I compost the vegetables and throw out the chicken bones. I don't know of any good use for them. Return the stock to the stove and continue simmering uncovered for an additional couple hours. This reduces the stock to about half its volume, making it really potent. I often dilute the stock when I use it - but it takes up much less room in the fridge or freezer this way. I usually let the bones cool then pick the extra meat off the bone to use in future soup.
Step 4: Take the pot off the heat and let it cool to room temperature before pouring it into a container and putting it in the fridge.
Step 5: When the stock has chilled it will turn very gelatinous. Like the picture below. A skim of solid fat will form at the top. Once the stock is chilled it is easy to scrape the fat off with a spoon. I use the fat for baking breads and browning vegetables. It adds some great flavor. Don't throw it away it's good stuff!
Step 6: The stock is ready to use. It will keep in the refrigerator for up to three days or in the freezer for 4 months. I use my stock to make polenta, soup, as the liquid in making the filling for enchiladas, and in almost every savory sauce I can recall.
Below is a picture of the chilled finished stock. Interesting, it almost looks like apple sauce.