%% Category::<h1><span class="material-symbols-outlined">local_library</span> </h1> %% > [!pdf] From the WWW > This is extracted from an article posted by Oregon State University on canning tomatoes <h1><span class="material-symbols-outlined">local_library</span>Canning tomatoes and tomato products. </h1> Created: Wed, Sep 17th 2025 #ingredients Ripening tomatoes are a familiar sight in Pacific Northwest gardens and fields during the late summer months. Because the storage life of fresh tomatoes is limited, many households preserve them for year-round enjoyment. Home canning is one of the most popular preservation methods. Processing times are scientifically determined. Several factors influence the length of time home-canned products must be processed. Therefore, it is extremely important to follow a tested recipe for canning tomatoes and tomato products (such as spaghetti sauce). Changes in the amount or type of ingredients and method of preparation can influence the processing conditions needed to guarantee safety. For example, adding vegetables to a tomato sauce recipe can change acidity, and overcooking can change consistency and density. *Products that are not prepared according to the research-based instructions in this publication should be frozen.* As a result of new research findings and changes in tomato varieties, tomato-canning recommendations have changed over the years. This publication contains the most current recommendations. Be sure to replace all previously published instructions to ensure a high-quality and safe product. These recommendations are effective for all varieties and sizes of tomatoes including heirloom tomatoes. Underripe or green tomatoes can also be preserved using these instructions. The instructions for crushed, whole or halved tomatoes are for peeled tomatoes. ## Adding acid Because of the variation in tomato varieties, acid must be added to all jars of canned tomatoes and tomato juice before processing to ensure safety. The acid may be added before or after the jars are filled with tomatoes. Acid must be added to both boiling water canning and pressure canning options. Acid Per pint Per quart Bottled lemon juice 1 tbsp 2 tbsp Bottled lime juice 1 tbsp 2 tbsp Citric acid USP 1/4 tsp 1/2 tsp Vinegar (5% acidity) 2 tbsp 4 tbsp If you are using bottled lime juice, do not use key lime juice. There may be undesirable flavor changes if using vinegar. Sugar may be added to mask the sour flavor of the acids (1 tsp per pint; 2 tsp per quart). ## Adding salt Salt is added to tomatoes for flavor, not to preserve them. Therefore, it may be omitted. If you use salt, add ½ teaspoon to each pint jar, 1 teaspoon to each quart jar.