Salsa and tomato sauce preparation tips

by Val Hillers and Richard Dougherty

Most salsa recipes are a mixture of low-acid foods, such as onions and peppers, with acid foods, such as tomatoes. Make sure you use the proper processing method and time for salsas and sauces to prevent possible food poisoning.



The type of tomato you use often affects the quality of salsas. Paste tomatoes, such as Roma, have firmer flesh and produce thicker salsas than large slicing tomatoes. Although both types make good salsas, slicing tomatoes usually yield a thinner, more watery salsa than paste tomatoes. Salsa can be thickened by adding tomato paste.

Canning is not a good way to use overripe or spoiling tomatoes. Use only high quality tomatoes for canning salsa or any other tomato product. Do not use tomatoes from dead or frost-killed vines. Poor quality or overripe tomatoes will yield a very poor salsa and may spoil.

Where recipes call for peeled or skinned tomatoes, remove the skin by dipping tomatoes into boiling water for 30-60 seconds or until skins split. Dip in cold water, then slip off skins and remove cores and seeds. You may substitute green tomatoes or tomatillos for tomatoes in any of these recipes.


Peppers range from mild to fiery in taste. Very hot peppers are usually small (1 to 3 inches long); mild peppers are usually bigger (4 to 10 inches long). Anaheim, Ancho, College, Colorado and Hungarian Yellow Wax are mild pepper  varieties. Choose a mild pepper when the recipe calls for long green chiles.

Small, very hot peppers provide a distinct taste to salsas. Jalapeno is the most popular hot pepper. Other varieties include Serrano, Cayenne, Habanero and Tabasco. Use rubber gloves when you cut or dice these peppers because they cause extreme irritation to the skin. Do not touch your face, particularly the area around your eyes, when you are working with hot chiles!

You may substitute bell peppers for some or all of the long green chiles. Canned chiles may be used in place of fresh.

Use only high quality peppers. Do not increase the total amount of peppers in any recipe. However, you may substitute one type of pepper for another.

The skin of long green chiles may be tough and can be removed by heating the peppers. Usually when peppers are finely chopped, they do not need to be skinned.

Hot peppers, such as the jalapeno, do not need to be peeled, but seeds are often removed.

If you choose to peel chiles, slit each pepper along the side to allow steam to escape. Peel using one of these two methods:

Oven or broiler method--Place peppers in a hot oven (400 degree F) or broiler for 6-8 minutes until skins blister.

Range-top method--Cover hot burner, either gas or electric, with heavy wire mesh. Place peppers on burner for several minutes until skins blister.

After heating, place peppers in a pan and cover with a damp cloth. (This will make peeling the peppers easier.) Cool several minutes; slip off skins. Discard seeds and chop.

Caution: Wear plastic or rubber gloves while handling hot chiles!


Tomatillos are also known as Mexican husk tomatoes. They do not need to be peeled or seeded, but the dry outer husk must be removed.


The acid ingredients used in salsa help preserve it. You must add acid to canned salsas because the natural acidity may not be high enough. Commonly used acids in home canning are vinegar and lemon juice. Lemon juice is more acidic than vinegar, but has less effect on flavor. Use only vinegar that is at least 5% acid and use only bottled lemon juice.

If you wish, you may safely substitute an equal amount of lemon juice for vinegar in recipes using vinegar. Do not substitute vinegar for lemon juice. This substitution will result in a less acid and potentially unsafe salsa.


Spices add flavoring to salsas. The amounts of spices and herbs may be altered in these recipes. Cilantro and cumin are often used in spicy salsas. You may leave them out if you prefer a salsa with a milder taste. For a stronger cilantro flavor, add fresh cilantro just before serving the salsa.

IMPORTANT: Follow the directions carefully for each recipe. Use the amounts of each vegetable listed in the recipe. Add the amount of vinegar or lemon juice listed. You may change the amount of spices, if desired. Do not can salsas that do not follow these or other research tested recipes. (They may be frozen or stored in the refrigerator.) Do not thicken salsas with flour or cornstarch before canning. After you open a jar to use, you may pour off some of the liquid or thicken with cornstarch.


Follow manufacturer's directions for pre-treating lids. Fill hot, clean jars with the hot salsa, being careful not to leave any salsa on the rims. Wipe jar rims with a clean, damp paper towel. Put on lids and screw on metal bands.


Processing in a Boiling Water Canner

  1. Use a rack to keep jars from touching canner bottom and to allow heat to reach all sides of the filled jars.
  2. Put jars into a canner that contains simmering water.
  3. Add boiling water if needed to bring water 1-2 inches above jar tops. Don't pour water directly on the jars. Place a tight-fitting cover on canner. (If you use a pressure canner for water bath canning, leave the cover unfastened and the petcock open to prevent pressure buildup.)
  4. Bring water back to a rolling boil. Set a timer for recommended processing time. Watch closely to keep water boiling gently and steadily. Add boiling water if necessary to keep jars covered.
  5. Remove the jars from the canner immediately after timer sounds. The food could spoil later if jars are left in hot water too long.

Cooling Jars

Put jars on a rack or cloth so air can circulate freely around them. Don't use a fan and avoid cold drafts.
Do not retighten screw bands after processing.

Testing for Seal

Test each jar for a seal the day after canning. Jars with flat metal lids are sealed if:

  1. Lid has popped down in the center.
  2. Lid does not move when pressed down.
  3. Tapping the center of the lid with a spoon gives a clear, ringing sound (this is the least reliable method).

If a jar is not sealed, refrigerate the contents and use soon or reprocess. Reprocess within 24 hours. When reprocessing, the salsa must first be heated to a boil before packing in hot jars. Wipe jar rims clean. Use a new lid and process for the full time listed.


Wipe jars. Label with the date and the contents of the jar. Remove the screw bands to avoid rust.
Store jars in a cool dark place. For best eating quality and nutritive value, use within one year. Heat, freezing temperatures, light, or dampness will decrease the quality and shelf life of canned food.

Before Using

Before opening each jar, look for bulging lids, leaks or any unusual appearance of the food. After opening, check for off-odor, mold or foam. If there is any sign of spoilage, destroy the food.



Saint John's Community Garden Society

Copyright � 2005 College of Saint Benedict | Saint John's University
All rights reserved.
Last revised on October 23, 2009.