It is that time of year again when produce becomes plentiful, and people begin dusting off their canners to preserve summer’s flavors for year-round enjoyment. Preserving salsas is a great way to get the most out of an abundance of peppers and tomatoes. However, there are a few things to know before canning a batch of your favorite condiment.

Safe canning depends on several factors. These include the acidity of the food (pH); the amount of water available in a food to support growth of microorganisms (water activity); and the amount of time a food needs to be processed (heat penetration) to ensure the coldest spot in the jar has received adequate heat treatment to destroy microorganisms.

Unfortunately, both tomatoes and peppers have a high pH, which — if not handled properly — can make your favorite canned salsa recipe turn deadly. The high pH, combined with a lack of oxygen in a jar, can support the growth of Clostridium botulinum, the microorganism that causes botulism. If you do have a favorite salsa recipe you wish to preserve, it is best to freeze it in food-grade containers or refrigerate and consume within a few days.

To help get you started, here is a recipe adapted from the National Center for Home Food Preservation:

Choice Salsa

6 cups peeled, cored, seeded and chopped ripe tomatoes

9 cups diced onions and/or peppers of any variety (see notes below)

1 and ½ cups commercially-bottled lemon or lime juice

3 teaspoons canning or pickling salt

Yield: About 6 pint jars

Never alter the proportions of tomatoes, vegetables and acid as it might make the salsa unsafe. Measure the chopped tomatoes, diced peppers and/or onions in dry measuring cups and the lemon or lime juice in a liquid measuring cup.

Use commercially-bottled lemon or lime juice to standardize the pH in the recipe. Although lime juice can be used, lemon juice will provide the most acceptable flavor for this particular recipe. For safety reasons, do not substitute vinegar for the lemon or lime juice. Do not use bottled key lime juice.


1. Wash and rinse pint or half-pint canning jars; keep hot until ready to fill. Prepare lids and ring bands according to manufacturer’s directions.

2. Dip washed tomatoes in boiling water for 30 to 60 seconds or until the skins split. Submerge immediately in cold water. Peel off loosened skins and remove cores. Remove seeds and chop into ¼- to ½-inch pieces.

3. Peel, wash, core and dice onions into ¼-inch pieces.

4. Wash and core bell peppers. Remove the seeds and membranes before dicing into ¼-inch pieces.

5. For hot peppers, wash and remove stems and remove as much of the seeds and membranes as you wish. Dice peppers into ¼-inch pieces.

6. Combine the prepared ingredients in a large pot, and add lemon juice and salt. Bring to a boil over medium heat while stirring. Reduce heat and simmer salsa for an additional 3 minutes, stirring as needed to prevent scorching.

7. Fill the hot salsa into prepared hot jars, leaving ½-inch headspace. If needed, remove air bubbles and re-adjust headspace to ½-inch. Wipe rims of jars with a dampened clean paper towel. Adjust lids and bands.

8. Process in a boiling water canner. For altitudes of 0-1,000 feet, jars need to be processed for 15 minutes. For altitudes of 1,001-6,000 feet, process jars for 20 minutes. Let cool, undisturbed, for 12 to 24 hours. Check seals for proper closure before storing jars. If the jars have not sealed properly, reprocess the salsa by bringing to a boil then simmering for 3 minutes then continue with steps 7-8.

Your local extension office can provide you with safe recipes for canning numerous types of salsas. Alternatively, you can download the PNW Extension publication on canning salsas by visiting Happy canning.

If you have a food safety question you would like to see appear in this column, send your question to us at

Stephanie Smith is an assistant professor and statewide consumer food safety specialist for Washington State University Extension. She can be reached at or at (855) 335-0575.

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