How to Safely Preserve Vegetables
This section covers three traditional food preservation techniques, canning, brining, and pickling, including:
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- How hot-bath processing differs from pressure canning.
- When is pressure canning required?
- How to preserve vegetables with brine.
- The process of pickling vegetables.
- Methods used to process and store jams, jellies, and preserves.
- Blanching and cooking vegetables and fruit before canning or freezing.
Introducing Vegetable Preservation Processes
Safe vegetable canning provides long-term storage of vegetables and prevents bacterial growth. It uses high-heat processing.
Similar, easier methods produce pickles and preserves. For safety, they rely on acid, salt or sugar to sterilize fruit and produce packed into clean, sterile jars. Brine allows safe fermentation of vegetables such as sauerkraut, kimchi, and brined leafy greens in open jars or crocks.
The Pressure-Canning Process. Home canning using mason jars with one-time-use lids and tight metal rings is fading from popularity. Canning relies solely on high-heat processing and careful attention to prevent bacterial growth and produce safe food. The canning process requires care and effort avoided by preserving vegetables by other means.
To be successful, canning jars and their contents all must be presterilized. The steps include boiling containers and the vegetables, packing with clean tools while still hot, carefully sealing, and pressure cooking at temperatures of as much as 230°F (110°C) for times that vary by the vegetable and the pressure cooker model used.
Improperly canned vegetables may bear a hazard for causing botulism by contamination during the preserving process. The tasteless, odorless, usually fatal, botulin toxin, along with other spoilage diseases, may cause jars to burst explosively due to high pressure.
The Pickling and Brining Processes. Pickled cucumbers and brined sauerkraut need simple packing in a boiling brine made of salt and vinegar. The steps include sealing and boiling jars of vegetables for 15–20 minutes in an open saucepan on a stove before cooling and storage.
Fresh pickles and sauerkraut may be made by brining washed, raw cucumbers and shredded cabbage in a loosely covered crock stored in a cool, dark spot or refrigerator at 35–45°F (2–7°C) for 4–6 weeks, then packing them loosely into jars and setting them in a household refrigerator for use in 2–4 weeks.
Always follow a recipe to can or pickle—they often are included in boxes of canning jars—and carefully prepare jars or containers to ensure safety.
Brining and Pickling Methods
Many vegetable gardeners enjoy the time-honored tradition of canning, brining, and pickling their garden’s produce and making jams and jellies from its fruit.
Home canning uses sterile glass mason jars with one-time-use lids and tight metal rings tightened onto the jars to seal them.
Brining, pickling, and making preserves are much simpler processes to accomplish.
Brining and pickling relies on salt brine to preserve vegetables, while sweet-condiment processes produce jams and jellies.
Easy-to-make pickled cucumbers need simple packing in a boiling brine made of salt and vinegar. Pack clean and sterile jars with the cucumbers or cabbage, then boil the full jars for 15–20 minutes in an open saucepan on a stove, cool, and dry.
Fresh pickles and sauerkraut also may be made by packing washed, raw cucumbers and shredded cabbage into a clean, loosely covered crock and filling it to cover with salt brine solution. Place the full crock in a cool, dark spot at 35–45°F (2–7°C) for 4–6 weeks to ferment.
After fermentation subsides, pack the pickled vegetables loosely into jars with fresh vinegar-brine solution and store them in a household refrigerator. Use within 2–4 weeks.
Always follow a recipe to can or pickle—they are found in boxes of canning jars and lids.
Sweet Preserves Method
Sweet condiments nearly everyone loves—jams, jellies, and preserves—use sterile preparation and sugar plus the acidic content of the preserved fruit or added pectin to prevent bacterial or fungal growth.
Clean jars are boiled in a water bath after packing to prevent contamination before cooling and storage. It is always important to follow a recipe with clear preparation guidelines when making sweet preserves.
Always process condiments using clean, undamaged mason jars and new self-sealing lids with retaining rings. Avoid screw-top glass containers or those with loose rubber rings held in place with a wire closure.
The equipment used for making sweet preserves are basic: a large saucepan, a larger pot for the water bath, canning jar tongs, and mason or jelly jars, plus slotted spoons, a wide-mouth canning funnel, a ladle, and a candy thermometer.
A few special terms are frequently found in jam and jelly recipes:
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- Headspace: the air space between the packed jam or jelly and the top of the jar.
- Jell Point: The temperature at which the fruit mix will thicken and set.
- Pectin: A jelling agent used to assist setting in berry preserves.
- Sealing: An airtight seal created during water-bath processing.
- Paraffin Seal: Household wax used to quick-seal jellies.