4
Testing Seals
After the jars have cooled, test the jar lids to be sure a vacuum seal has formed. Press down on the center of the flat lid to determine if
it is concave (stays down when pressed). Then, remove the screw band and gently try to lift the lid with your fingertips. If the center
does not flex up and down, and you cannot lift the lid off, the lid has a good seal.
Detecting Spoilage
If up-to-date instructions, processing times, and canning pressures are followed carefully, spoilage is uncommon. However, it is still
recommended to check for signs of spoilage before tasting any canned food. Check for a broken seal, gassiness when opening, mold,
sliminess, cloudiness, or unpleasant odors.
If any of these signs are present, discard the food.
As a safeguard against using canned low-acid foods and tomato products which may be affected with spoilage that is not readily
detected, boil food 10 minutes for altitudes up to 1,000 feet above sea level. Extend the boiling time by 1 minute for each 1,000 foot
increase in altitude. Many times odors that cannot be detected in the cold product will become evident by this method. If, after boiling,
food does not smell or look right,
discard it without tasting
.
How to Use your Presto
®
Pressure Canner
IMPORTANT:
Do not attempt to use your canner before reading these step-by-step instructions for pressure canning in your canner.
Prepare food according to the processing procedures in the specific recipe and follow the recipe and instructions carefully.
1. Be sure your canner is thoroughly cleaned and working properly. Before each canning season, have the dial gauge checked for
accuracy. Also check the sealing ring, the overpressure plug, and the rubber adaptor of the pressure dial gauge. Replace these
parts when they become hard, deformed, cracked, worn, pitted, or unusually soft. Use only genuine Presto
®
replacement parts.
2. Check the Mason jars for nicks, cracks, and sharp edges. Check the screw bands for dents or rust. Use only jars, lids, and screw
bands in perfect condition so an airtight seal may be obtained. Wash and rinse the jars, lids, and screw bands. Pour hot water into
the jars and set them aside until needed. Follow the manufacturer’s directions for preparing the lids.
3. For recipe information, see your booklet titled
Recipes and Helpful Hints for Presto
®
Pressure Canners
. Select fresh, firm food.
Sort the food according to size and clean thoroughly. Prepare the food according to the specific recipe; always use current,
research-tested procedures, recipes, and timetables. Fill the hot jars promptly with food and liquid to the recommended level.
Allow ½-inch headspace for fruits. Most vegetables and meats require 1-inch headspace due to expansion during processing.
Work out the air bubbles with a clean, nonmetallic spatula. Wipe the sealing edge clean with a damp cloth. Center the flat lid on
the jar rim. Adjust the screw band according to the manufacturer’s directions.
4. Position the canner on a level gas or electric coil burner and range only. These canners are not designed to work on electric glass-
top or induction burners and ranges. If you use the canner on a tilted burner or range, it may interfere with the operation of the
pressure regulator.
For electric ranges, use the element that most closely matches the diameter of the canner bottom, which is the
portion that comes in contact with the element.
CAUTION!
Do not use on any outdoor LP gas burner or a gas range over 12,000 BTUs. If you use an element
that is too large or one over 12,000 BTUs, the canner may soften and the bottom may warp. It may also result in
property damage and/or personal injury.
5. Place
3 quarts of hot water
and the canning basket or rack in the canner; for hot packed foods, the water can be
heated to 180°F, or not quite boiling. To prevent water stains, add 2 tablespoons of white vinegar to the water in
the canner.
Note:
3 quarts of water are needed regardless of how many jars are being canned.
6. Place the filled jars on the canning rack immediately after each jar is filled. Always use the canning rack as the
jars may break if set directly on the bottom of the canner.
7. Hold the cover up to the light and look through the vent pipe (Fig. B) to be certain it is clear before placing the
cover on the canner. If it is clear, proceed to the next step. If it is blocked, clean the vent pipe with a small brush
or pipe cleaner (Fig. C).
8. Check to be sure the overpressure plug is seated properly in the cover (Fig. D).
9. Place the cover on the canner, aligning the
V
mark on the cover with the mark on the body handle. Press down
on the cover handles to compress the sealing ring and then turn the cover in the direction indicated (clockwise) to
close until the cover handles are above the body handles.
Do not rotate the cover beyond this point.
10. Using a high setting on your stove, heat the canner until a steady flow of steam can be seen, heard, or felt coming
from the vent pipe (Fig. E). Allow this steam to flow from the vent pipe for 10 minutes to vent, or exhaust, all the
air from the canner. Reduce the heat on your stove, if necessary, to maintain a steady, moderate flow of steam.
11. Place the pressure regulator on the vent pipe (Fig. F, page 5). If the heat was reduced for venting, adjust it to a
high setting and heat the canner.
Fig. B
Fig. C
Fig. E
Fig. D
