Water Bath Canning Times

• Water bath canning requires little more than a large, deep pot and canning rack, and is a perfect project for beginners. Cooking times for tomatoes vary greatly based on their preparation method, but using this method you will spend anywhere from 40 to 90 minutes cooking canned tomatoes. Whole or half tomatoes canned with no liquid or with tomato juice take the longest at 90 minutes for both pints and quarts, while tomato juice and tomato sauce are the quickest cooking at 40 minutes for pints and 45 minutes for quarts. Crushed tomatoes and whole or half tomatoes canned in water take 45 minutes for pints and 50 minutes for quarts.

Pressure Canning Basics

• Pressure canning is the other method used for tomato canning and requires a calibrated pressure canner to complete safely. Based on the amount of pressure used when canning with this method, your cooking times will vary, however, cooking times are always quicker than using the water bath canning method. Whole or half tomatoes canned in tomato juice or with no added liquid take the longest at 40 minutes using 6 pounds of pressure, or 25 minutes using 11 pounds of pressure for both pints and quarts. Whole or half tomatoes packed with water are the quickest, completed in 15 minutes using 6 pounds of pressure, or 10 minutes using 11 pounds of pressure for both pints and quarts. Tomato juice, crushed tomatoes and tomato sauce should be cooked for 20 minutes using 6 pounds of pressure, or 15 minutes using 11 pounds of pressure.

Canning Tomatoes Safely

• It is extremely important that you follow all recommended cooking times when canning tomatoes to ensure their safety. Additionally, it is important that you acidify tomatoes canned in a pressure canner and those canned using the water bath canning method. Acidify tomatoes using either bottled lemon juice or citric acid to ensure that the level of acid in the finished tomatoes is sufficient to prevent the growth of the dangerous clostridium botulinum toxin. This bacteria, though widely present in the spore form throughout the environment, reproduces only when in anaerobic environments. However, it cannot reproduce in acidic conditions of pH 4.6 or less, making acidifying your home-canned foods important.

Cooking Time Variations

• Water boils at a lower temperature at higher altitudes, making it necessary to adjust cooking times for water bath canning, and pressure in the case of pressure canning for changes in altitude. For water bath canning, if you live in a location that is 0 to 3000 feet above sea level, standard cooking times apply. However, you should add five minutes to the total cooking time for each additional 2000 feet above 3000 feet above sea level. For pressure canning, use standard cooking times and pressure for altitudes up to 2000 feet above sea level. For each additional 2000 feet above this, add 1 pound of pressure and keep the cooking time the same.