Utah State University Extension says you should never use your own recipe when it comes to canning salsa. Since salsa contains acidic and low-acid ingredients, the required preservation process is determined by the recipe. Whether you use a boiling water pitcher or a pressure vessel is determined by the salsa’s ingredients and how it’s made. That’s why the experts recommend using a tested recipe, such as that provided by the USDA or the National Center for Home Food Preservation (NCHFP).
by the USDA and NCHFP Guide for canning tomato products it is important to strictly follow the tested recipes, which can also be found in the guide. Changing the number of tomatoes, onions, or peppers in the recipe may make the salsa unsafe to eat. It’s important to have the right balance between acidic (tomatoes) and low-acid (onions and peppers) ingredients. It’s okay to change the amount of spices and replace bottled lemon juice with vinegar. But those are the only safe replacements. So the next time you want to save your extra tomatoes by canning some salsa, don’t forget to pick a trusted recipe.