I make a tomatillo salsa/sauce that I want to can. It's roasted tomatillos, roasted peppers, garlic salt, cumin, cilantro, onions and garlic. Do I have to add an acid to can it, or are the tomatillos acidic enough?
Thanks for your question. Your recipe sounds delicious. It should be eaten fresh or frozen; it is not safe for canning. Salsa is a combination of low-acid foods, so must have acid (vinegar, lemon juice, lime juice) added to it to make it safe for canning.
It's important to use a recipe from a reliable source (Extension Service, USDA, Ball Blue Book). These recipes have been tested to include the correct proportions of each ingredient so that the salsa has enough acid to make it safe for canning and enough of the other ingredients to result in a high quality, tasty product.
We have a great tomatillo salsa recipe in our "Salsa Recipes for Canning publication" available at http://extension.oregonstate.edu/fch/sites/default/files/documents/pnw_395_salsarecipesforcanning.pd...
Oh yes -- tomatillos have about the same amount of acid as tomatoes.