Safe Canning Tips


Wednesday, June 24th 2009, 2:31 pm
By: News On 6


Safe Canning and Freezing

Gardeners from around the state are enjoying the fruits of their labor as they consume the various fruits and vegetables they have grown in their gardens or on their fruit trees. Those who do not garden may find a bounty of offerings at the local farmers market.

What do you do when you have an overabundance of fresh fruits and vegetables? You have the option of canning or freezing to help preserve this bounty. "Canning and freezing both are excellent ways to prolong the freshness of just-picked fruits and vegetables. If done correctly, you can savor the flavor all year long," says Charlotte Richert, Tulsa County OSU Extension Educator, family and consumer sciences.

Canning Tips:
When canning foods always follow directions from a reliable source dated 1988 or later and be careful not to over pack jars as this can cause inadequate processing and result in unsafe food. Nearly all fresh vegetables must be processed in a pressure canner for the required USDA processing time. Pickled foods such as acidified tomatoes and cucumber pickles can be safely processed without pressure in a boiling water bath when directions are carefully followed.
If using a pressure dial gauge, make sure you get it checked at the OSU Extension Center each year. This is a simple check and is important for safely processing food.

It is critical to allow steam to escape for 10 minutes before closing the valve or putting the weight on the vent of the pressure cooker. This allows the inside temperature to correspond to that of the pressure gauge. Processing begins with the appropriate pressure has been reached. Then an adequate cool down period must be allowed. This is typically about 30 minutes for pints and 45 minutes for quarts. Wait another 10 minutes before opening the pressure canner.

If you discover an unsealed jar within 24 hours after canning, the food can safely be re-canned but the quality will be lowered. Remove the lid to check the rim of the jar for any nicks and change the jar if needed. Add a new, treated lid and reprocess using the original processing time.

"Properly canned food will retain optimum eating quality for at least a year when stored in a cool, dry place," Richert said.

Freezing Tips:
Blanch vegetables before freezing them. This is the process of heating or scalding vegetables in boiling water or steam for a short amount of time. This process slows or stops enzymatic action that reduces flavor, color and texture.

In addition, blanching removes dirt and organisms from the surface of vegetables and helps slow down vitamin loss. It also softens vegetables, making them easier to pack in freezer containers.

Blanching time is crucial and varies with the vegetable and size. Underblanching stimulates the activity of enzymes and is worse than no blanching. Overblanching causes loss of flavor, color, vitamins and minerals.

Blanching times for vegetables commonly grown in Oklahoma can be found at the Web site for the National Center for Home Food Preservation at http://www.uga.edu/nchfp/index.html. Water blanching is the most common method for blanching home frozen vegetables. Tools needed include a wire blanching basket and a large kettle with a fitted lid.

Use one gallon of boiling water for each pound of prepared vegetables. Place the vegetables in the wire basket, lower it into the boiling water and begin blanching time as soon as the water returns to a boil, usually within one minute. Brown said if the water takes longer than one minute to return to a boil you are using too many vegetables for the amount of water.

"Once you've blanched the vegetables, quickly and thoroughly cool them to stop the cooking process. To cool, plunge the basket of vegetables immediately into a large quantity of cold water, 60ºF or below. Change water frequently or use cold running water or ice water. If ice is used, about one pound of ice for each pound of vegetable is needed. Cooling vegetables should take the same amount of time as blanching. Overcooked vegetables lose flavor, color, vitamins and minerals," she said. "Make sure to completely drain the vegetables as well. Inadequate draining before freezing, slow freezing or temperature fluctuations above 0ºF also can affect the quality, texture and appearance of your vegetables."

Richert said it is important to start with high quality fresh food at optimum maturity and freshness because frozen food is only as good at the quality with which you start.

"Keep in mind that freezing doesn't kill all bacteria, yeasts and molds in food, but it does keep them from rapidly multiplying when food remains at 0ºF or less," she said. "However, surviving organisms can multiply when foods are thawed."