canning under pressure august 2020
TRANSCRIPT
Canning Under Pressure
Home Food Preservation
Vegetables
Beans
Meats
Mixtures that contain low acid foods
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Low-Acid foods must be processed at 240°-250° FOnly can be achieved under pressure in a pressure
canner. (not a pressure cooker)
To destroy harmful microorganisms
• Botulism
• Food Spoilage
Multi cookers have not been studied regarding how temperatures and pressure in them relate
to the canning process.
Harmful microorganisms may still be present making the canned product unsafe.
At sea level 10.5 pounds of pressure (PSI) will get to 240° F
Pressure must be increased depending on altitudeP
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Time needed at pressure depends on
• Food
• How the jars are filled or packed
• Size of jars
National Center for HomeFood Preservation
University Extension websites, includingFood.unl.edu
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Do not pressure can foods that don’t have research -based
processing times. Freeze instead.
Read individual food recipe for specific information
Combination foods
No noodles, milk or thickening agents
Do NOT deviate from the recipe
Omitting salt
Salt is added for flavor only
Add salt substitutes when serving
Some low acid foods have no
research-based processing times...
• jellied cranberry sauce
• pumpkin
• your own creations
DIAL GAUGE WEIGHTED GAUGE
Hold 4 quart size jars upright on
the rack with the lid in place
Pressure Dial Gauge - has a pointer which moves over a readable
dial and indicates the pressure within the canner.
Weighted Gauge - adjusts to maintain 5, 10, 15 lbs of pressure in
the canner. Correct pressure is obtained when the regulator begins
a gentle rocking motion. See instruction manual for specific
directions.
Pressure regulator/Counterweight – acts as a safety device to
prevent pressure in excess of 15 pounds from building in the
pressure canner. Known also as weight valve or pressure gauge.
Vent pipe/Petcock/Steam vent – pressure regulator fits on the
vent pope and allow excess pressure to be released.
Vent/Cover lock (Safety valve) –As you start to heat the unit, it
automatically releases air from the pressure cooker. Primarily
useful in locking the cover and acts as a visual indicator of this
equipment that slides up when a pressure build-up is present.
Sealing ring/gasket – During cooking, the sealing ring forms a seal
between the cover and the body of the cooker.
Overpressure plug - will automatically release pressure if the vent
pipe becomes clogged and pressure cannot be released as normal.
The design of this device, however, varies widely by brand and
model.
Jar rack –Placed in bottom of canner to hold jars off the bottom of
the unit while canning.
Safety Fuse - thin rubber plug designed to release pressure from
the canner if the temperature or the pressure becomes
dangerously high.
Vent pipe/Petcock/Steam vent
Add water to canner• Start with 2-3 inches of hot water, longer process
might need more
Add jars• Place filled, closed jars onto rack
• Use jar lifter, do not tilt jars
Close canner lid• Leave the weight off or open petcock
• Heat at highest setting until steam flows freely
Steps to successful pressure canningP
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Vent the canner• Maintain a high heat
• Exhaust continuously for 10 minutes
⚬ This is done to ensure the atmosphere in
the canner is entirely steam and no air.
Place weight on canner or close
petcock
Steps to successful pressure canningP
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Steps to successful pressure canningP
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gMaintain the pressure• Adjust heat slowly to maintain steady pressure at or
slightly above the recommended pressure
• If pressure drops below required level
⚬ Bring pressure back to required level
⚬ Restart the timing process
Pressurize• Start timing the process when the gauge shows the
indicated level, either on the dial or when the weighted
gauge starts to jiggle or rock
Steps to successful pressure canningP
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Cool and Depressurize• When timing is complete
⚬ Turn off heat
⚬ Remove canner from heat, if possible
⚬ Allow canner to depressurize naturally
￭ 30 minutes - pints
￭ 45 minutes - quarts
￭ Newer models have vent locks that show
depressurization
Remove weight or open petcock• Wait 10 minutes before removing lid
• Lift lid away from you
Remove jars• Use a jar lifter
• Place on a clean towel leaving 1 inch
between jars
• Leave undisturbed for 12-24 hours
Steps to successful pressure canningP
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Label and store• cool, dark place
Wash jars and lids• to remove residue
Inspect seal within 24 hours• Remove bands
• Check for seal
• If not sealed,
⚬ refrigerate
⚬ freeze
⚬ reprocess immediately
Steps to successful pressure canningP
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• Only safe method for all meats and vegetables
is pressure-canning
• NEVER process these foods using the boiling
water method
• If processed according to the approved USDA
recommendations, they are safe to eat
• To be safe boil before eating for 10 minutes
below altitudes of 1,000 feet adding 1 minute
for every 1,000 feet of elevation
• Microwave heating is not recommended
Using Pressure Canned foods
Canning Checklist
• Use an up-to-date, research-based recipe
• Adjust for your altitude
• Only use canning jars in good condition
• Use 2-piece lids
• Use new flats every time
• Fill jars to proper headspace for food
• Check your pressure canning gauge yearly
• Check your canner gasket and safety fuse
yearly
Nancy FrecksExtension Educator
Nebraska Extension
The University of Nebraska does not discriminate based on race,
color, ethnicity, national origin, sex, pregnancy, sexual orientation,
gender identity, religion, disability, age, genetic information,
veteran status, marital status, and/or political affiliation in its
programs, activities, or employment.
Canning Under Pressure
Nancy UrbanecExtension Assistant
Nebraska Extension
Canning Under PressureResources
• Fundamentals of Consumer Food Safety and Preservation:
Master Handbook Copyright 2015 Washington State
University.
• National Center for Home Food Preservation: nchfp.uga.edu
• food.unl.edu/canning-freezing-and-drying