The pot should be large enough to fit a batch of canning jars. Place the elevated canning rack in this pot, and fill halfway with water. Bring to a simmer. If you are using an actual canner, the rack should have come with it. If you are just using a pot, you can use a cooking rack so long as it fits in the pot.  If you plan on doing a lot of canning, particularly of low-acid items like tomatoes, you should think about investing in a pressure canner. They take less time and are reliable. If you have a pressure canner and are planning on using it now, follow the instructions provided with the canner when you bought it. If you do not have a cooking rack, you can just place a washcloth on the bottom of the pot. This will keep the glass jars from cracking against the metal of the pot. Once all the jars have been placed, lower the canning rack. Pour enough water into the simmering canning pot to cover the jars by two inches. Place the lid on the canning pot and bring to a boil. If you are using pints, boil the jars for 40 minutes. If you are using quarts, boil the jars for 45 minutes. You should also keep in mind that cooking time will vary based on what altitude you are canning at.  0 to 1,000 feet (0.0 to 304.8 m) above sea level: 35 minutes for pints, 45 minutes for quarts. 1,001 to 3,000 feet (305.1 to 914.4 m): 40 minutes for pints, 50 minutes for quarts. 3,001 to 6,000 feet (914.7 to 1,828.8 m): 45 minutes for pints, 55 minutes for quarts. Above 6,000 feet (1,828.8 m): 50 minutes for pints, 60 minutes for quarts. Allow the pot to cool for 20 minutes, and then remove each jar with the lifter. Place the jars on a towel. Allow jars to cool for a whole day, and then test the seal on the jars by pushing down in the center. The center should not move. If it does, use the tomatoes immediately. Do not be surprised if you see the canned tomatoes floating above a layer of liquid inside the jar--this is totally normal.
املأ الوعاء الذي ستستخدمه كمُعلّب بالماء. ضع البرطمانات على رف التعليب. ارفع غطاء وعاء التعليب وأطفأ النار. احفظ البرطمانات محكمة الغلق في خزانة مطبخ باردة واستخدمها في غضون عام.