How to Can Tomatoes

Home Canned Tomatoes from Fresh Tomatoes (boiling water method)

• Tomatoes - about 23-25 lbs to make 7 quarts of tomatoes. Of course, you can reduce the size of batches.
  
• lemon juice - bottled, about 1/2 cup
  
• 1 Water bath Canner (Tomatoes are on the
  border between the high-acid fruits that can be preserved in a boiling-water bath and the low-acid fruits, vegetables and meats that need pressure canning, that’s why we add lemon juice)
  
• 1 large pot (to scald the tomatoes)
  
• 1 small pot or kettle -for water to sanitize the
  lids.
  
• Paring knife, for coring tomatoes
  

• Pint or quart canning jars
• Lids - thin, flat, round metal lids with a gum
binder that seals them against the top of the
jar. They may only be used once.
• Rings - metal bands that secure the lids to the
jars. They may be reused many times.
• Jar grabber (to pick up the hot jars)
• Lid lifter (optional) –it has a magnet to pick the
lids out of the boiling water where you sanitize
them.
• Jar funnel
• Large spoons and ladles • Clean damp cloth

Get the jars and lids sanitizing. The dishwasher is fine for the jars; especially if it has a "sanitize" cycle. I start that while I'm preparing everything else, so it's done by the time I'm ready to fill the jars. If you don't have a dishwasher, submerge the jars in a large pot (the canner itself) of water and bring it to a boil. If using a dish washer, be sure to let it go through the rinse cycle to get rid of any soap!
Get the canner heating up. Fill the canner about 1/2 full of water and start it heating (with the lid on). Get a large pot of water heating for blanching the tomatoes for peeling.
Start the water for the lids. When it boils, pour it over the lids and rings. Cover and let sit until you are ready to seal the jars.
Remove the tomato skins. Put the tomatoes, a few at a time, in a large pot of boiling water for no more than 1 minute (30 - 45 seconds is usually enough) Then plunge them into a waiting bowl of ice water. This makes the skins slide right off of the tomatoes! Then you can cut the tomatoes in quarters and remove the tough part around the stem and any bruised or soft parts. Why remove the skins? They become tough when you cook them!
Heat the quartered tomatoes just to boiling, stirring to prevent burning. Before you fill each jar with tomatoes, add 1 Tablespoon of lemon juice to the bottom of each pint jar (2T for a quart. jar). The additional acid makes all types of tomatoes safe for boiling water bath canning, and retains color and flavor.
Fill the jars with heated tomatoes. Leave 1⁄2 inch head-space at the top. Wipe off the rim of the jar with a clean damp cloth, then put the flat part of the lid on, and the ring. Just screw them on snugly, not too tight. Be sure the contact surfaces (top of the jar and underside of the ring) are clean to get a good seal!
Carefully lower the jars into the canner and make sure they are covered with at least 1 inch of water. Bring the water back to boiling. Process the jars in a boiling-water bath for 35 minutes for pints and 40 minutes for quarts. After the processing time has passed, lift the jars out of the water and let them cool without touching or bumping them in a draft-free place (best to leave them overnight). Once the jars are cool, check that they are sealed, verifying that the lid has been sucked down. Just press in the center, gently, with your finger. If it springs up and down (often making a popping sound), it is not sealed. If you put the jar in the refrigerator right away, you can still use it. Some people replace the lid and reprocess the jar, but it is best to heat the contents back up, re-jar them (with a new lid) and process for the full time in the canner. With all the extra heating, and processing, you may loose some quality,
but it will be safe to consume. This document was adapted from the "Complete Guide to Home Canning," Agriculture Information Bulletin No. 539, USDA, revised 1994.