You've been running batches through the pressure canner all day... You're tired and on the last run. You walk through the living room on your way back from the potty and think, "I'll just sit down here for a few minutes before I check on things."
Pretty soon, you open your eyes! You fell aslseep! There's a loud rattling sound coming from the kitchen.... What were you working on again?! Oh no! The pressure dial is maxed out, the weight is rocking madly and it sounds like the canner has run dry... The burner on the stove is still on high!
Welp, you've gotten yourself into a problem now. If things have not blown up yet; here's what to do to fix it:
DO NOT TOUCH THE CANNER. I repeat, DO NOT TOUCH THE CANNER.
Take a deep breath.
Carefully reach behind the canner and turn OFF the burner.
Also turn off whatever timer you had set. Note if any processing time was remaining.
Remove yourself, family members and pets from the kitchen.
Go back to the comfy chair in the living room AWAY from the canner.
Take everyone out to supper if that hasn't been done yet.
Once you calm your racing heart, you can wait for things to calm down in the kitchen or put yourself to bed.
If you stay up, wait until that dial gauge is down to zero and the nipple is down before opening the canner to see what kind of a mess you've got.
Don't try to continue to work tonight; give yourself a break and try again another day.
Many food items can be reprocessed or the product can be frozen to be used. It's most likely not a total loss.
IF you were woken by the canner over-pressure plug or canner itself exploding:
Make sure anything else that might cause burns has already blown up before proceeding.
Turn off the burner.
Go back to the chair or go out to supper.
Allow everything to cool down before attempting to clean up the mess.
Any jars that did not bust can be refrigerated or emptied and the contents frozen.
You can remove alot of stains on countertops, walls, ceilings, with a paste of baking soda and water.
Repair or replace anything damaged by the explosion.
Try canning again!
NEVER WALK AWAY FROM YOUR CANNER FOR ANY LENGTH OF TIME. You can take the time to go pee. Time loss is a real thing. Take a timer with you to the bathroom so you don't forget what you're doing. Or set a second timer in the kitchen to go off in 5 minutes so you are reminded to go back in there.
This applies to the electric pressure canners as well. They aren't as "safe" as they seem. (This includes Instant Pots and Crock Pots. Our local church burnt down because of an unattended slow cooker. Always unplug your toaster!) Waterbath canning allows for a longer break but will still need to be monitored for water level and being topped off as time passes.
Canning is not a walk away deal. Please keep this in mind while processing. Keep yourself and your family safe.
Don't let this discourage you. Canning is so much fun and having all that yummy food on the shelf is satisfying.
Just remember to keep yourself engaged in the process and if you need to leave during processing; make a contingency plan. Have someone educated on what to do ready to take over. Don't start processing until you have blocked off the time to finish the project.