NDSU Extension Service - Ramsey County


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Canning Veggies

Canning Veggies


Canning can be an economical method of preserving vegetables to enjoy throughout the year, and the nutrient value is often as good as or better than fresh produce. National movements promoting both the environmental and health benefits of consuming more locally grown foods has spurred a renewed interest in home gardens, farmers’ markets and home food preservation, but if not done safely, your canned foods can become contaminated with the bacteria,

Clostridium botulinum, the deadly neurotoxin that causes botulism, thrives in under-processed, low-acid, home-canned goods. A single nibble or sip of botulism-laced food, ingested as soon as three or four days after processing, can prove fatal. Why take that risk? C. botulinum and the other bacteria that contribute to spoilage are easily destroyed when cooked for the right amount of time at 240 to 250 degrees F—the temperature in a properly-regulated pressure canner.

Start your canning adventure by checking your pressure canner. Make sure your pressure canner has a tight-fitting cover, clean exhaust vent (or petcock) and safety valve, and an accurate pressure gauge. Use a pressure canner that holds at least 4 quart jars. Smaller pressure canner-saucepans are not recommended for home canning as they heat up and cool down too quickly to ensure adequate heat penetration using the processing schedules specified in this fact sheet. There are two types of pressure gauges: weighted and dial gauges. Dial gauge need to be checked for accuracy before using but weighted gauges need only to be cleaned before using. Check gauges each season before use.  NDSU Extension Service Offices provide that service free of charge Call our Ramsey County Office at #662-7027 for more info.

 Next check your canning jars and lids. Discard any jars and closures with cracks, chips, dents or rust, since defects can prevent an airtight seal. Use jars designed specifically for home canning. Use only the half-pint, pint and quart sizes. Wash jars in hot, soapy water and rinse well before using. Keep the jars hot until they are filled and placed in the canner. This will help prevent jar breakage. Do not use commercial food jars (mayonnaise, pasta sauce, etc.) as they break easily in pressure canners and may not seal.

Select only fresh, young, tender vegetables for canning. The sooner you can get them from the garden to the jar, the better. For ease of packing and even cooking, sort the vegetables for size and ripeness. Wash all vegetables thoroughly. Soil often contains bacterial spores, the form of bacteria which is hardest to destroy. Don’t let vegetables soak; they may lose flavor and nutrients. Handle them gently to avoid bruising.

The hot-pack method is recommended for all low-acid foods, including vegetables.

 For the hot pack, heat vegetables in water or steam before packing. Then cover with the boiling cooking liquid or water. Loosely pack the hot food. For both hot and raw pack, use enough liquid to fill around and cover the food. Read the directions for each vegetable for the amount of space to leave between the top of the food and the top of the jar. This headspace is important to obtain a good seal.

Salt may be added to each jar, if desired. Salt is added only for seasoning and does not help preserve the food. If salt is used, canning salt is recommended to prevent the liquid from turning cloudy. Use 1/2 teaspoon salt per pint.

To remove any trapped air bubbles, insert a nonmetallic spatula between the food and the jar. Slowly turn the jar and move the spatula up and down to allow air bubbles to escape. Add more liquid if necessary to obtain the proper headspace. Wipe the jar rim with a clean damp paper towel to remove any food particles. Place pretreated lid on the jar. Screw on the band fingertip tight.

    Find and read the manufacturer’s instructions for your pressure canner. General directions for using pressure canners are as follows:

  • Put 2 to 3 inches of hot water in the canner. Place filled jars on the rack, using a jar lifter. Fasten canner lid securely. Leave weight off vent port or open petcock.
  • Maintaining a high heat setting, exhaust steam 10 minutes.
  • Place weight on vent port or close petcock. The canner will pressurize in the next three to five minutes.
  • Start timing the canning process when the pressure reading on the dial gauge indicates that the recommended pressure for your altitude has been reached, or when the weighted gauge begins to jiggle or rock. Regulate heat under the canner to maintain a steady pressure at or slightly above the correct gauge pressure. Quick and large pressure variations during processing may cause unnecessary liquid losses from jars. Weighted gauges should jiggle or rock slowly throughout the process.
  • When the timed process is completed, turn off the heat, remove the canner from the heat if possible, and let the canner depressurize. Do not force-cool the canner by pouring cold water over it. When the pressure registers zero, wait a minute or two, then slowly open the petcock or remove weighted gauge. Unfasten the cover and tilt the far side up so steam can escape away from you.
  • Carefully remove jars from canner and place on rack, dry towels or newspapers. Allow jars to cool untouched, away from drafts, for 12 to 24 hours before testing seals.

    After the jars have cooled, test the seals on the jar lids. Press flat metal lids at the center of the lid. Lids should be slightly concave and not move when pressed. Remove screw bands and wipe jars with a clean, damp cloth. Label sealed jars with contents, canning method and date. Store in a clean, cool, dry, dark place.

    Treat any unsealed jars of food as fresh. The food should either be eaten immediately, refrigerated, frozen or reprocessed. The food can safely be reprocessed if the unsealed jar is discovered within 24 hours. To re-can, check the jar sealing surface for tiny nicks and change the jar, if necessary. Repeat the entire canning process, using a new lid.

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