I found 2 recipes that seem close to what I want to do. One is from a Better Homes and Gardens Canning publication and one is from Putting Up More by Stephen Dowdney. Both use oil and butter to saute the onions and both use vinegars and/or wine to acidify the onions.

The BHG recipe recommends a 4oz jar with 1/4" headspace and processing in BWB for 5min. The Putting Up More states that the Ph needs to be below 4.3 and then hot packing the jars and inverting the jar to seal it. Personally, the PUM method freaks me out. What I am wondering is: can I BWB can the onions as long as they are acified with the vinegar or wine? I am thinking about making the PUM onion jam, but putting it into the smaller 4oz jars and BWB canning them. Will this work??? Where does the risk of botulism come in? And why can't I use oil/butter to cook the onions? I read that the oil can slow the heat penetration when BWB, so would the smaller 4oz jars offset this problem? I also have a pressure cooker, so if BWB doesn't work, can I use my pressure cooker? And I have read that you can oil pack (but not can) some products. Would that be a better way to preserve the onions?

Ok - so there are a lot of questions. :)

BHG Recipe:
Vidalia Onion and Maple Conserve
1/4 cup butter
1/4 cup olive oil
2 1/2 lbs vidalia onions
2 tsp sea salt
2tbls fresh thyme
1 tsp black pepper
1 cup pure maple syrup
1/4 cup sherry vinegar

Cook everything and then stir in vinegar. Ladle into jars and BWB

Putting Up More
Sweet onion jam
1/4 cup butter
3 tbls olive oil
4lbs sweet onions
1 cup sugar
1/2 cup dark brown sugar
1/2 cup balsamic vinegar
1/4 cup dark red wine
1/2 tsp salt
Caramelize onions with butter/oil and set aside. Cook all other ingredients until thick and Ph is 4.3 or below.

In looking at the ratio of butter/oil to the amount of onions, PUM is pretty small so would this negate the oil issue?

First, your immediate issue is either your freezer or how you're packing the onions because they shouldn't be freezer-burned. That is an issue worth resolving because if one item is getting freezer-burned others are also - and that adds up to a lot of waste.

Second, the issue with fats is not limited to heat penetration. Fat coats the onions (which are already low-acid), inhibiting penetration of the vinegar. Botulism likes a low-acid environment, so it's possible to add acid to a recipe but still have an environment in which low-acid pockets of product reside. That is definitely a problem.

I looked at the BH&G recipe. As magazines go they are one of the more reliable canning sources, but whether that particular recipe is reliable I have no idea. BH&G has not provided information about the credentials of their test kitchen staff (i.e. regarding their background in the kinds of safety issues which pertain to canning) or their test protocols.

I can say for myself that is a type of canning recipe I would not feel comfortable sealing in a jar unless I knew it was Extension Service/USDA/NCHFP vetted. Since it isn't, I'd keep on freezing it and resolve whatever issue is causing the problem there.

It sounds like Dowdney is evaporating out the water to bring the pH down to 4.3, but again, depending upon where/how the mixture was tested, it might be 4.3 but contain pockets of product where the pH is considerably higher. He isn't even canning, he's just slapping lids on jars. His methods are idiosyncratic, to say the least. I might make the recipe but I'd never follow his instructions.

Hypothetically you could pressure can these onions using the time for fish and be sure what you canned is "safe" but by then it would be mush. The focus of testers is to develop recipes which balance safety, texture and flavor. It's an impossible task for the home preserver.

Carol

Personally, the PUM method freaks me out.

Kudos to you for that. Trust your instincts.

Both of your recipe sources are "questionable" - to be polite - resources for safe canning info. We have discussed both books here several times and the consensus is that both books need to be used with great care.

Dave

4 large red onions, peeled and thinly sliced

1/2 cup packed brown sugar

2 cups dry red wine

6 tablespoons balsamic vinegar

1/2 teaspoon each salt and pepper (or to taste)

IMPORTANT: if you intend to can this, do not use oil! The onions will provide plenty of moisture to the pan.

Place the onions in a pot over medium heat. Stir in the sugar. Cook uncovered for 3o minutes or so, or until the onions are soften and start to brown and caramelize. Stir frequently. If the onions produce a lot of moisture, cook down until liquid has almost completely evaporated.

Stir in the wine, balsamic vinegar, salt, and pepper. Bring to a boil, then reduce heat and simmer15-20 minutes until the liquid has reduced and begins to thicken. Taste and correct seasoning.

Note: The cooking time will vary widely depending on the water content of your onions. The times given are based on average supermarket onions. If you have fresher onions, they will require more time for the moisture to evaporate.

Ladle relish into hot sterile jars. Leave a 1/2 inch head-space. Process in a hot water bath for 10 minutes for half-pint jars. See Home Canning Basics for more information about the canning process.

Post your recipe, maybe someone can help you find a similar one to can, but it sounds like freezing is the only option (I second the Foodsaver suggestion!).

But as others have said, best to find out just why freezer burn is a problem for you since it needn't be. I have frozen onions that are over 2 years old with no freezer burn.

Dave

I've made the Caramalied Red Onion relish recipe from the Complete Book of Small Batch Preserving. I like it---very tasty, very onion-y. But it's definitely a relish---has a distinct vinegary-y tang, not mistaken for right-off-the-fire caramalized onions (which I LOVE!).

The authors of SMALL BATCH PRESERVING are reliable and have good food science credentials; I would not hesitate to follow any of their recipes.

My favourite use for this recipe is to drain the onions well and use them to make a caramalized onion/barbecued chicken pizza. Yum!

Zabby