I gotta know - WHY don't they recommend canning anything but juice into them? WHY don't they recommend them for pressure canners? I just discovered this fact on Penn state's extension website last night. They gave no explanation other than "don't do it". A few other websites said the same with little to no explanation.

I have been canning chili toms into them for years. They work great for having one jar for one batch of chili. I use half the lids and can fit four into my 22 quart Mirro - 1 quart more per batch than I could if I used quart jars. I just fail to see any downside. My daughter is 6 and my son is three. As they grow, larger can sizes become more effective in cost and time savings in preserving food. A wide mouth lid costs 19 cents on a pint jar, a quart jar, OR a half gallon jar...

So whats the deal?

Primarily it is because there is no calculated processing times for them - for anything. So processing time is purely a guess on your part.

But make it a thick something (something other than juice) and you add to that density and heat penetration issues that results in cold islands within the jar where bacteria can remain unaffected.

Make it a thick AND a low-acid something in that jar and a guessed-at processing time and you have a very risky jar of food.

From the NCHFP FAQs:

What can I process in half-gallon canning jars?
At least one canning jar manufacturer is selling half-gallon canning jars. That manufacturer has a printed note on the top that says half-gallon jars are only used for some highly acidic foods in a boiling water canner, with instructions to call a toll-free number for the instructions. When we last called, the only choices are grape juice and apple juice, as we also recommend.

The only processes that USDA, the National Center for Home Food Preservation and the University of Georgia have to recommend for half-gallon jars are for very acidic fruit juices (and juice only): Apple Juice (http://www.homefoodpreservation.com/how/can_02/apple_juice.html) and Grape Juice (http://www.homefoodpreservation.com/how/can_02/grape_juice.html). This process time is not to be used for tomato juice, for example.

There are no other research-tested processes for half-gallon jars. Boiling water processes for other foods for jars larger than those published with recipes (usually pints and/or quarts) cannot be extended by any formula to a larger jar.

We are aware that there are historical recommendations for canning foods in half-gallon jars. However, these are not currently accepted or endorsed by the USDA, Cooperative Extension System or U.S. manufacturers of home canning jars.

Of course the choice to follow the guidelines or not is always yours.

Dave

I only can chili toms in them, so the toms are hot when packed. I also only pressure can, no BWB. Maybe I've just been lucky. Of course, I've also been lucky to not have been hit by a bus. This year, I'm considering apple cider in half gallons as well. It's nice to know at least that is approved.

You may have been lucky. With additional citric acid, maybe the odds were in your favor or maybe it's just that you're using the tomatoes in longer-cooked foods like soups or chili where any potential toxins would be destroyed by boiling.

Carol

But they look awfully thick in those jars. As Carol said, assuming you are also adding the required citric acid or lemon juice to them you had a hedge on the risk but not if they contain peppers too.

My primary question would be how you determined the processing time that would be required? Using the same time as for quarts wouldn't be nearly enough and doubling or even tripling it would still be just a guesstimate only and would affect thew texture and quality as well.

Apple juice (filtered for solids) is approved and fine to do using the given 10 mins. BWB processing for half-gallons. But apple cider (unfiltered) is a different animal and much thicker due to all the solids so no processing time is given for it.

Dave

I think you hit the head on the nail - no officially researched data and no desire to do so. As long as the few of us that still home can have our pints and quarts, we should be happy with them. I imagine the pint-and-a-halfs will be unacceptable for canning as well, beings they haven't been researched.

I've canned dozens of these in the past 10 years. It's simple quartered tomatoes with 1 onion and half a pepper per can. The batch is near boiling when they're loaded into the hot jars. Three tablespoons of lemon juice. I added 5 minutes to the 25 minute time for quarts (which happens to be the exact same time for pints in my canner's book) I honestly never knew that half gallons have been considered dangerous all along.

I've done some research online and have found some sources for "outdated" info on how to can into these death traps. One person posted a list of products out of his 1982 Kerr canning book on another forum. Seems they were safe until the early 80's... I've printed off the info and will tuck it into my canner's manual. Tomato sauce calls for 45 minutes at 10 pounds and stewed tomatoes call for 65 minutes in BWB.

I'll go to 45 minutes at 10 pounds for the last batch of the year tonight, just to be less unsafe.

Honestly, I'm sure that I seem glib about the whole deal, but I do care greatly for the health and safety of the food my family eats. I also tried to find any articles telling of how someone got sick off any home canned food. Unless I'm as bad at searching on Google as i was on this forum there were only a couple in the last 10 years. My family can get sick just as fast on a jar of commercially canned peanut butter.

Finally, just cause I do it, doesn't make it right. Don't go canning in half gallon jars on my advice. I'm responsible for myself and my family, not yours.

You are absolutely right that older canning books did provide times and instructions for processes not approved now. That is primarily a function of where the research was at the time. Each USDA guide reflects "best practice" for that era.

It wasn't until 1976 that the first study identified four varieties of low-acid tomatoes. It wasn't until 1988 that acidification of tomatoes was added to the USDA guidelines. So a 1982 guide is going to miss a lot of things only later research revealed.

Pumpkin butter used to be approved for canning until testing demonstrated the pH of home-grown pumpkins was all over the place and it was nigh unto impossible to determine a universally safe processing time. So it was pulled from the books. Food safety doesn't change; our knowledge does.

As I'm sure you're aware, pint-and-a-half jars are not an issue for any canning recipe for which a quart time is provided. You can always process in a smaller size and no one is going to "rescind" approval of pint-and-a-half jars.

But half-gallons are double the size of quarts, so they present particular challenges. And there are so many factors that affect processing time, you might as well throw a dart at a board as guess what an adequate time might be.

The time required for heat to penetrate to the center of the food in the container is extremely important. The heat-penetration rate is affected by:

A. The size and shape of the container: quarts take longer to heat up than pints.
B. The ratio of solids to liquid: vacuum-packed corn kernels take longer to heat up than kernels in brine.
C. The type and size of the pieces in the container: corn and peas heat up faster than yams or boneless chicken breasts.
D. The amount of fat: fat is a thermal insulator.
E. The type of heating medium being used: wet steam heats cans faster than dry air.

But, everyone decides for himself/herself where the boundaries are regarding what is preserved in the home. We try to clarify, but you're "the decider."

Carol

They are processed for the quart time, assuming one is given, and are only used for those recipes which provide a quart processing time.

Dave

I am glad I discovered the warnings about using them. I will be even more vigilant about getting the jars good and hot and the stock to boiling before loading the pressure canner. I'm adjusting my processing time from 30 minutes to 45 minutes.

Thanks very much to all comments. I'll keep watching for more input.

That's fine as long as you understand that you are canning a densely-packed, low-acid, mixed and untested recipe in your jars (tomatoes with peppers and onions) with an unknown pH, that hot jars and boiling stock have no effect on many bacteria and fungal spores (esp. c. botulinum) so is not relevant, and that even your increased processing time is likely not sufficient and has never been tested.

The PC processing time for quarts of mixed vegetables is 90 mins. and even 90 min has been proven to be insufficient in jars of some foods that are densely packed. So personally I don't see how 45 min for quart and a half jars could be sufficient.

But if you are comfortable with that much risk it's yours to take.

Dave

I don't know if the Ball Blue Book says anything in the introduction or not, but it's one example of the many less-obvious complications of canning.

As you can see from the lengthy list of issues associated with jar size and processing time, there are multiple factors involved.

Carol

You, Carol, and all the others have been very helpful on this thread. Until a couple days ago, I had not known that there was much risk at all in canning in half gallons. Now that I know there is a little more than I expected, I am adjusting my personal Best Practices. You make a very good point about the onions and peppers. I will also cut them out of the mix. I usually use one half gallon and one quart in my chili. I will find an acceptable chili tomato recipe and use it for the quart.

So, I'm sure the only way to completely satisfy all concerned is to have some sort of half gallon jar breaking ceremony. I cannot do that. The changes I am making to my half gallon processing will bring the level of risk to an acceptable level for my piece of mind.

This whole deal has got me thinking about an event that happened between my 6 year old daughter and me last spring.

She had come home from kindergarten one afternoon after a Police Officer had come to the school and preached seat belt safety to the school. After she got off the bus and walked in, I loaded her up to get my 3 year old son from daycare. The driveway to our farm is 1800 feet long. I didn't buckle my seatbelt because I was going to grab the mail on my way out. She told me I should because I was going to die in an accident. I told her I was in my driveway and found the risk to be acceptably low because we couldn't achieve a high rate of speed and there is no traffic on the driveway. She insisted I should do it because the police officer told her that I'd die if I didn't. So I explained to her acceptable risk.

Say you want something off the top shelf in the cupboard and there is no adult nearby. There's three ways to do so -
1. Wait until and adult arrives and ask him or her to get you the item.
2. Get a step, carefully climb on the counter, and get the item. (she does this all the time, except now she doesn't need the step)
3. Put on a pair of rollerskates, set a trampoline at the base of the counter, skate at the trampoline and bounce onto the counter. (she laughs pretty hard at that)

Which is the safest? Which is the most efficient? I may have been unintentionally treading too close to the "rollerskate" scenario. With all your help, I feel I am firmly in the middle scenario.

Thanks.

Not wanting to start up an argument, but just wondering if this USDA recommendation of only using 1/2 gallon jars for juice is based on an actual clinical case of food poisoning or just theoretical reduction of risk. I couldn't find any cases with an internet search.

I'll confess to making dill cucumber pickles last year in 1/2 gallon jars - well within my personal food safety perimeters, but won't repeat. The jars are just too much of an odd size in the refrigerator.

I only have 6 jars, and they'll be used in the future for saving fruit juices until I get around to making jelly.

Nope, not at all. :) They are great for fermenting in. Same for the gallon jars. And for dry storage. Personally would have no problem with making fermented or straight vinegar pickles in them either and have used them for apple juice, cider, and fresh tomato juice (with 3T lemon juice) in the past. In other words, things that have their own built in high acid protection or will be fridge stored not canned.

I'm just curious if there has ever been an established link between 1/2 gallon jars and botulism/food poisoning.

Not that I know of but they were part of the cold pockets testing NCHFP did (see their publications) and the follow-up 6 and 12 month culturing project. Beyond that I would suspect it is the lack of demand/interest in using them vs. cost of doing the testing that limited any further testing on them.

Like buying #10 cans of foods issues - limited demand and preservation of contents after opening problems.

Dave

As an aside, I was in Walmart the other day and they're now have some sort of 'survival aisle ' with #10 cans of stuff, 150 gallon water tanks, etc.

I buy tomato paste in #10 cans because we go through enough of it in a canning season that it saves a considerable amount of time, money, and effort.

2. Of that population even fewer can foods susceptible to botulism.

3. Of the foods that are canned in half-gallon jars that are susceptible to botulism, not all actually develop botulism toxins.

4. Of the jars that would contain botulism toxins, some contain foods which are sufficiently cooked to inactivate toxins.

5. Of the cases of botulism in all categories that do occur, not all are reported to the CDC. That is an individual physician responsibility. The CDC and other agencies freely acknowledge the system for reporting all instances of food-related poisonings is archaic and inaccurate. The word "broken" is not too extreme.

Draw your own conclusions, but the dearth of documented cases is hardly proof there is no risk. The proof of risk must be in the testing and currently that barely exists, except for more generalized testing regarding the consequences of inadequate heat penetration in canned goods.

I might also add that some chunky foods, even higher-acid mixtures, may have low-acid "islands", making adequate heat penetration even more crucial.

None of us is telling anyone what to do, merely laying out some relevant information. How or if that's applied is an individual decision.

Comments about "forbidden" canning in pint-and-a-half jars and half-gallon jar-smashing ceremonies are an injustice and lower the tone of the discussion.

Carol

Sure you can. It's your life.

You can also play chicken with Interstate Hwy. traffic or play Tarzan on high-voltage power lines if you want to. Thankfully most of us know better and care enough to not encourage others to do it either.

Dave

This is a totally false statement, and one needs to understand what a spore is. Some bacteria (and C. botulinum is one of them) has the ability to be present in two states. The vegetative state and the spore state. Spores are NOT active bacteria, but are in a dormant state for the purpose of surviving hostile environments. The heat you apply to kill the active c. botulinum ( the vegetative state) will not be enough to kill the spores. When you slap that lid on the jar, and a vacuum is established, you have just given the spores in low acid foods the exact environment they need to turn vegetative, start multiplying into a large colony and producing the toxin. The toxin is what sickens you. You simply cannot handle all foods alike when canning. It's just not that simple.

%%%%%%%%%%%%%

You are mixing two things here:
Low acid is different issue. If it is unsafe in 1/2 gal. container, it is also unsafe in pint container. Same goes for botulism.

"truthseeker" is technically right when he say "you can can anything in any size container". That is PROVIDEd it is fully cooked and acidifyed adequately. Let me say what I think:

You bring to boil (whatever you want to can) in an open pressure cooker. Then put the lid on, continue until it builds up temperature/pressure( about 240F ?). Give it required time to stabilize(from 212 to 240F). After a while, Take the weight off the cooker , let it depressurize. Now pour stuff into pre sanitized 1/2 gal glass container( as you would do with other sizes) close it. Let it cool. Check to make sure that it has created vacuum. You are done.

The reason that they( NCF.., BAL..) have not bothered to come up with a procedure for larger container (because they were some lazy .blanky.) does not mean that anything other than what they have experimented is UNSAFE. It is not a rocket science to calculate heat penetration and equilibrium for just about anything. It has to do with the conductivity of the material and the temperature differential. Most food items (Mostly H2O) have similar heat conductivity.

Disclaimer: Food safety is important . Use your best judgement. It is your life , your family's life.

I am not sure I understand that statement, but if it means the NCHFP and Ball are too lazy to complete studies, I'd have to say it shows an interesting bias to ascribe the worst possible motive to a lack of data in this area, particularly when there are so many more likely reasons.

To kill botulism spores you must reach a minimum temperature of 240 degrees. I suppose theoretically you could PC something at pressure then pour it into a sterilized jar and slap on a lid, but then you have a weak vacuum and seal, allowing for the development of new spoilage mechanisms within the jar and faster deterioration of product. From my perspective not a very rational approach.

Carol

No, it's not "rocket science" to calculate, but it is engineering. Not only does "conductivity" (usually used as an electrical term, but I see you're talking about heat conduction) play a part, but so does convection. Most of the heat penetration into a large jar of food will be due to convection, not conduction.

In the normal method of heating the jar (even after pouring boiling or almost-boiling food in), there will be cold pockets in the interior of the jar - the larger diameter it is, the larger the cold pockets in the interior will be and hence the longer it needs to be processed (and/or a higher processing temperature, as in a pressure canner). Of course, the density of the food plays a part too. The same holds if you are heating the food in a sealed PC and can't stir it occasionally - the pressure and hence the temperature of the food that is in contact with the walls/rack of the PC and the steam will be at high temperature but depending on the density the interior will be lower where convective currents are not able to heat the food.

In the method you and truthseeker advise, the outside of the jar (assuming sitting at room temperature) will cool more quickly than the interior, but that does not mean that the interior has gotten to a safe temperature for a long enough time to kill the spores, as linda lou and calliope have pointed out. As Carol said, theoretically you could bring the food in an open container (or no container) up to 240 in a PC and put in a sterilized jar, but there are no pressures/times calculated for that, just as there aren't for 1/2 gal containers, not because someone was "lazy" but because there was no funding/interest in doing so, since most people don't use such large containers.

Now, if you have a degree in hydrodynamics and want to calculate the conductive and convective heat patterns for every type of low-acid food food and very volume of said food you would cook in a PC and then pour into a sterilized jar (only cooking 1/2 gal at a time? Or more?) and you feel comfortable that the food has been rendered safe, that's your choice. But I'd rather go with empirical evidence gained through multiple tests than with calculations because I'm afraid I might have missed a variable.

And of course as Carol said the cooling food will only pull a weak vacuum on the lid so you might find all your food has spoiled due to other biologicals once the seal has popped in storage. Time, energy, and food wasted.

No, it's not "rocket science" to calculate, but it is engineering. Not only does "conductivity" (usually used as an electrical term, but I see you're talking about heat conduction) play a part, but so does convection. Most of the heat penetration into a large jar of food will be due to convection, not conduction.
&&&&&&&&&&&&&&&&&&

I already mentioned "HEAT CONDUCTIVITY". That is the worst scenario for heat transfer. Convection can FACILITATE it further. But when you put a jar inside a canner, there won't be any convection(displacement of the contents within the jar).

TEMPERATURE
And I proposed a method to heat the contents in a pressure cooker. I believe it can get a temperature of 240F, to kill the bad bacteria. Then you fill the 1/2 gallon jar ....seal ...END

But if you have a bigger canner, you can do it just lik a pint jar, only GIVE IT MORE time.
ACIDITY
It is the acidic environment that prevents the bacteria from multiplying, becoming active and producing toxins. So if minimum pH is 4.6 and you have 4.4, you are safer than required.

I still think that the statement :
" YOU CAN CAN ANYTHING IN ANY SIZE JAR"
is correct and valid. You just have to know how to do it.