You need to let the gauge return to zero, then tip the weight cautiously to make sure there isn't any residual pressure. If you hear a little hiss, rest the weight back and wait a few minutes more.

Once you have silence, remove the weight (i.e. regulator) and wait 10 minutes. Then remove the lid and take out the jars.

Do not leave jars in the canner. If you notice a lot of bubbling and activity in the jars when you remove the lid, you can wait a few more minutes for things to settle before lifting jars out, but no more than that.

There are some nasty organisms that find the nice warm environment of a closed canner a happy breeding ground, so don't leave the jars in the canner beyond the recommended time.

Carol

Agree. Jars need to be removed as soon as the proper cool down steps have been followed as Carol detailed above. It isn't safe to do otherwise.

Dave

Thanks, Carol. That makes sense. Do you know I'd those 10min of wait time after I remove the weight are for operator safety or food safety?

Thanks for the confirmation, Dave!

Do you know I'd those 10min of wait time after I remove the weight are for operator safety or food safety?

They are primarily for food safety although it can keep you from getting burned.

They part of the required processing time and also help prevent siphoning of liquid out of the jars.

If you haven't already checked out the step by step guide Using Pressure Canners at NCHFP you really need to as it helps understand all these points and several more.

Dave

Thanks, Dave. I do have a highlighted & underlined copy. But what I find frustrating about the USDA guide is that while they give details about *what* to do, I find the guideline skimpy regarding *why*. As I decide which calculated risks I'm willing to take, I need to know the why.

I'm not looking for an endorsement of those calculate risks ;) here or from the USDA - I just like to know the nitty gritty of why each step is important.

Thanks!

As I said before I think, the 'whys' comes from the classes. So if you need all the theory and details behind each guideline then look for certification classes in your area.

If they tried to include all the whys and wherefores info in the published guidelines they would be the size of a textbook and most would never care to read through all of them so they are written for the average home food preservationist who just wants to know how to do it safely.

Risk assessment requires substantial education and experience regardless of the subject matter. Or as we often say here, first you learn to crawl and then you can learn to run. :)

Dave

When the NCHFP or Ball Blue Book lists a processing time for pressure-canned foods, they're just giving you the actual minutes at pressure.

However, in testing, the venting time + the time to come up to pressure + the processing time + the time to come back to zero + the wait time are all calculated in determining a safe processing time.

One reason smaller pressure cookers are not suitable for canning is that the time to come up to pressure and the time returning to zero are much briefer, resulting in a total processing time that's too short.

Many home food processors are still not aware of the wait time requirement.

I hope this clarifies things for you.

Carol

Thanks! Maybe I should look into a class. Full disclosure: I'm a university professor and tend to over think these things! I seem unable to just happily follow the directions :) Normal people would sensibly avoid the textbook version of the USDA guidelines, but I'm excited to hear that such a thing exists!

I'm a university professor and tend to over think these things! I seem unable to just happily follow the directions :)

Understandable. But it reminds me of a current TV commercial that asks "you wouldn't trust your auto mechanic to clean your teeth so why would you ask your dentist about tires?"

It is impossible for any of us to be fully informed specialists in all subjects. Sometimes, like it or not, we just have to accept that those who ARE specialists in their chosen field, be it astrophysics or food science, know what they are doing and trust in their information. :)

Check with your local extension office about taking a MFP (Certified Master Food Preserver) course for starters.

Dave

"Check with your local extension office about taking a MFP (Certified Master Food Preserver) course for starters."

Just a note that this program isn't available to everyone. For example the University of Illinois Extension ended their MFP program last year. No more courses or MFPs available to the public. I hope this is not the case in other states.

Sadly so. We have no funding. It takes so much work to put on a training. Hours and hours of prep, plus the actual classes. Most of the classes are online courses instead of actual hands on. Some cost, but the Univ. of Georgia one is free.

There are still many scheduled for 2012 and 2013 per a Google search. Indiana has one scheduled as does Oklahoma, several in California, Missouri, Oregon, here in Arkansas, etc. so it can't hurt to check with surrounding states if yours is no longer offering one.

Don't know if they are online or in person as I didn't review them all in depth and some of the 2012 ones have already been done - it is more of an off-season thing - but worth investigating.

Dave

Thanks, Dave. That might be a fun winter thing.