The basic ingredient of soup is stock, and the better the stock, the better the soup. Becoming familiar with the ways different ingredients effect its taste is essential to becoming accomplished at making really good soup from what is available in your house. Stock is one of the easiest and most economical foods to prepare. From beginning to end, the actual hands on preparation time for stock is less than 20 minutes. You can buy stocks at grocery stores. Several are organic, and almost all brands have a low sodium option. But the difference in both flavor and cost between store bought and home made is huge.

Here’s everything you need to know to make your own delicious soup stock from scratch:

1. The Magic Stock Bag

If you eat fresh vegetables and cook with garlic, onion and fresh herbs, you have the primary ingredients for delicious stock. All you need is a plastic bag, a twist tie and a freezer. Every time you cook, put the tips, ends and old-but-not-dead vegetables in the bag and freeze it, over and over again until you are ready to make stock.

Vegetables to Use: onions, garlic, celery, carrots, fennel, summer squash, white potatoes (skinned), tomatoes, and light colored root vegetables.

Vegetables Not To Use: A general rule is avoid ingredients that will create a weird looking color or add a strong flavor. Any of the lettuce family (not enough flavor), dark, leafy greens (spinach, chard, kale), any of the cabbage or chicory family, broccoli and its relatives, winter squash, green beans and their relatives, radishes and others with deep coloration (beets, red onions).

Keep chicken, beef, lamb, etc. scraps and bones in their own bag

Keep a separate fish stock bag that includes only: crab shells, shrimp skins and tails and uncooked fish skin. You can combine it with your vegetable stock bag when you are ready to make fish stock.

2. Vegetables do not have to be perfectly ripe.

Limp is OK; mold is not.

3. Flavor

In addition to bones or chicken parts, onions, garlic and herbs provide the main flavor in stock. Green onions are fine. Most light colored skins, seeds and small stems are fine too because they will strain out.

Two or three carrots add a gentle sweetness. Four or five turn the stock orange and make it way too sweet.

Leftover fresh herbs and the stems of herbs like parsley, basil, tarragon, thyme, etc. really add flavor to stock. Avoid rosemary and watch sage because a little goes a long way.

Salt and pepper are flavor boosters. Use them conservatively when the stock is cooking. Taste it when it’s cool and add more salt if necessary.

Finally, and this is important, dirt has flavor, bad flavor. Clean the dirt off vegetables before freezing or putting them in stock.

4. Freezing Stock

I use stock as a base for sauces and marinades in order to add flavored liquid to things that need it and to make soup. So I freeze stock in containers of several sizes: quarts for dinner soup and one bowl left over; pints for soup for two; half pints for sauce bases and 2 oz. containers for just a little bit.