The Do’s & Don’ts of Food Preservation
Safely preserve your harvest bounty to enjoy for months to come.
by Dorina Espinoza, Humboldt/Del Norte UC Master Food Preservers
Whether you find yourself with an abundance of home grown produce, or you score a large quantity from your favorite local farmer, chances are high that as you deepen your connection to locally grown food, you will find yourself wanting to learn to preserve some of what you grow or purchase for later use.
There are several methods you can employ to preserve food, including canning, freezing, drying (dehydrating), and fermenting. No matter which you choose, safety must be your top priority. These guidelines from the Humboldt/Del Norte Master Food Preservers will help ensure that your preserved foods are safe and delicious.
Tested Recipes – Are you still hanging on to that recipe from your mom or grandmother? Sure, you made it through alive but the practice is likely not safe. Please only use tested recipes – your loved ones will be grateful! And when you find safe and tested recipes, follow the recipe exactly as written and resist the temptation to tweak! You can find tested recipes and safe food preservation information on these sites:
- National Center for Home Preservation
- USDA Food Safety
- University of California Master Food Preservers
Low-Acid Foods – You must use a pressure canner (not a boiling water canner) for low-acid foods like vegetables, meat, poultry, seafood, legumes, and mixtures that contain these foods.
A pressure canner cooks foods at high temperatures (240-250° F) to destroy microorganisms that cause botulism. One cannot smell, taste or see botulism so please don’t take the risk.
Label Food – Always write the name and date of preserving your delectables.
BOILING WATER CANNING
Jar Seal – Fill the jar to the level stated in the recipe. If the jar has too little or too much product, you may not get a good lid seal. Once filled, wipe the rim and threads of your jar with a clean moist towel to ensure a good seal. Place the lid on the jar and screw the band until you reach slightest resistance, then tighten the screw band another 1 to 1½ inches.
Jar Lifting – Move the jars in and out of the canner with a jar lifter and in an upright position. Never tilt the jars as that could cause food to touch the lid and break the seal.
Processing Time – Set the timer for processing only after the water starts boiling. You may lower the heat but keep at a full boil. If the water stops boiling during processing, turn the heat on its highest setting, bring the water back to a vigorous boil, and re-start the timer using the total original processing time.
Storing Jars – If any jars fail to seal, refrigerate and enjoy quickly. Store sealed jars in a cool place out of direct sunlight or fluctuating temperatures and without ring bands. If a jar did not completely seal, the lid will lift off the jar rim during storage and you will know not to consume the food from that jar. Enjoy properly sealed preserves within one year.
Preparing Food – Fruits and vegetables should be washed thoroughly prior to freezing. Before freezing, vegetables should be blanched, quickly cooled in an ice bath, and drained thoroughly.
Containers for Freezing – Plastic freezer bags are great for dry-packed foods with little or no liquid. Rigid plastic sealable containers are good for all types of foods including liquids. Canning jars are suitable for cold temperatures but do not use regular jars as they break easily at freezer temperatures. When freezing liquids, allow space for liquid expansion.
Freezer Temperature – Frozen foods are best kept at 0° F. Consider buying a freezer thermometer to place in the freezer where it’s easy to read.
Food Temperatures – To ensure the safety of your food, do not allow food to stay in the temperature danger zone (40°F-140°F) for more than two hours. This is true in preparing foods to freeze and thawing foods to eat.
Thawing Frozen Foods – Foods that contain fish, meat, eggs or other high protein ingredients should be thawed in the refrigerator or microwave.
Food Selection – Pick fresh and fully ripened food at peak quality and flavor. Thoroughly wash and drain. Discard food that has decay, bruises or mold.
Methods – Dehydrators are reliable in controlling temperature and air circulation. Conventional ovens can be used with the door propped open to provide circulation (convection ovens allow air to circulate with the door closed). All ovens should maintain a temperature of 130-150° F for drying non-meat foods.
Drying Fruit – Pretreating fruit with an acidic solution (ascorbic or citric acid) helps destroy harmful bacteria.
Drying Vegetables – Almost all vegetables (except peppers, onions, and mushrooms) should be blanched before drying. Add citric acid (¼ tsp. per quart of water) to destroy harmful bacteria.
Conditioning – Conditioning helps even out the moisture among all food pieces. Place dried food in a large, tightly closed container. Stir or shake the container each day for 2-4 days then check the food to make sure it is dry enough for storage – not sticky or tacky. If too moist, return to dryer for several more hours.
Please reach out to the Humboldt/Del Norte Master Food Preservers if you have any questions. Call 707-445-7351 or visit our website at ucanr.edu/mfp for preservation information including videos, recipes and classes.