any air bubbles with a nonmetallic spatula or a tool to free air bubbles. Add more prepared food or liquid to the jar after releasing the air bubbles to maintain the recommended headspace. Before applying the two-piece caps, always release air bubbles and leave the headspace specified in your recipe. These steps are critical for creating a vacuum seal and preserving your food.
3 Wipe the jar rims with a clean, damp cloth.If there’s one speck of food on the jar rim, the sealant on the lid edge won’t make contact with the jar rim and your jar won’t seal.
4 Place a hot lid onto each jar rim, sealant side touching the jar rim, and hand-tighten the screw band.Don’t overtighten because air needs to escape during the sealing process.
Step 4: Processing your filled jars
With your jars filled, you’re ready to begin processing. Follow these steps:
1 Place the jar rack in your canning kettle, suspending it with the handles on the inside edge of the kettle.
2 Place the filled jars in the jar rack, making sure they’re standing upright and not touching each other.Although the size of your kettle seems large, don’t be tempted to pack your canner with jars. Only place as many jars as will comfortably fit yet still allow water to move freely between them. And always process jars in a single layer in the jar rack. If your recipe calls for the same processing times for half-pint and pint jars, you may process those two sizes together. Otherwise, don’t process half-pint or pint jars with quart jars because the larger amount of food in quart jars requires a longer processing time to kill any bacteria and microorganisms.
3 Unhook the jar rack from the edge of the kettle, carefully lowering it into the hot water, and add water if necessary. Air bubbles coming from the jars are normal. If your jars aren’t covered by 1 to 2 inches of water, add boiling water from your reserve teakettle or saucepan to achieve this level. Be careful to pour this hot water between the jars, instead of directly on top of them, to prevent splashing yourself with hot water.
4 Cover the kettle and heat the water to a full, rolling boil, reducing the heat and maintaining a gentle, rolling boil for the amount of time indicated in the recipe.Start your processing time after the water boils. Maintain a boil for the entire processing period.If you live at an altitude above 1,000 feet above sea level, you need to adjust your processing time. Check out “Adjusting Your Processing Times at High Altitudes” later in this chapter for details.
Step 5: Removing your filled jars and testing the seals
After you complete the processing time, immediately remove your jars from the boiling water with a jar lifter and place them on clean, dry kitchen or paper towels away from drafts, with 1 or 2 inches of space between the jars.
If you are using single-use lids, don’t attempt to adjust the bands or check the seals — simply step away and allow them to cool completely. If you are using reusable lids, allow the jars to cool for 5 to 10 minutes and then tighten the bands securely, using a clean dish towel to protect your hands from the hot metal and glass. The cooling period may take 12 to 24 hours.
After your jars have completely cooled, test your seals on the single-use lids by pushing on the center of the lid (see Figure 4-2). If the lid feels solid and doesn’t indent, you have a successful vacuum seal — congratulations! If the lid depresses in the center and makes a popping noise when you apply pressure, the jar isn’t sealed. Immediately refrigerate unsealed jars, using the contents within two weeks or as stated in your recipe. (See the nearby sidebar, “Reprocessing unsealed jars,” for do-over advice.)
FIGURE 4-2: Testing your jar seal.
Test a reusable lid by removing the metal band from the cooled jar and slightly lifting the jar off the work surface, holding on to just the lid. A properly sealed jar can be lifted by the lid. An unsealed jar — you guessed it — will allow you to lift that lid right back off again.
REPROCESSING UNSEALED JARS
Jars may not seal for several reasons: You may have miscalculated the processing time, pieces of food may not have been cleaned from the jar rim, you may have left an improper amount of headspace, or the sealant on the lids may have been defective. The safest and easiest method for treating processed jars that didn’t seal is to refrigerate the jar immediately and use the product within two weeks.
If you want to reprocess jars that didn’t seal, you can do that. But keep in mind that reprocessing your food takes almost as much time as making the recipe from the beginning. The only time to consider reprocessing jars is if every jar in the kettle doesn’t seal.
To reprocess unsealed jars, follow these steps:
1 Remove the single-use lid and discard it. If using a reusable lid, inspect it for damage, wash and sanitize the lid and gasket, and try again.
2 Check the edge of the jar for damage.If the jar is damaged, discard the food in case a broken piece of glass fell into the food.
3 Discard any damaged jars.
4 Reheat the food.
5 Follow the step-by-step instructions in this chapter for filling your jars, releasing air bubbles, and processing your sterilized, filled jars.
6 Reprocess the filled jars for the recommended time for your recipe.
7 Check the seal after your jars have completely cooled.
Step 6: Storing your canned food
After you’ve tested the seal and know that it’s good (see the preceding section), it’s time to store your canned food. To do that, follow these steps:
1 Remove the screw bands from your sealed jars.
2 Wash the sealed jars and the screw bands in hot, soapy water.This removes any residue from the jars and screw bands.
3 Label your filled jars, including the date processed.
4 Store your jars, without the screw bands, in a cool, dark, dry place.
Adjusting Your Processing Times at High Altitudes
When you’re canning at an altitude higher than 1,000 feet above sea level, you need to adjust your processing time (see Table 4-1). Because the air is thinner at higher altitudes, water boils below 212 degrees. As a result, you need to process your food for a longer period of time to kill any microorganisms that can make your food unsafe.
TABLE 4-1 High-Altitude Processing Times for Water-Bath Canning
| Altitude (in feet) | For Processing Times Less Than 20 Minutes | For Processing Times Greater Than 20 Minutes |
|---|---|---|
| 1,001–1,999 | Add 1 minute |
Add 2 minutes
|