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Mason Jar Canning is one of the easiest ways to get started down the path of preserving local bounty year round for your pantry. For almost two centuries now this method has been utilized to capture seasons in air tight vessels to be opened throughout the year giving both sustenance and nostalgia of the past harvest in those months where the soil has nothing to give.

Science has played a major role in developing canning for safety from its early stages but has also homogenized its outcome, if the rules are followed to a T you are often left with same textured product that leave much of that crisp vibrant experience of fresh ingredients on the back burner. The method I will give a detailed recipe for today also uses science to reverse the notion that all canned goods must be mush.

In theory pressure canning works and is the safest bet for all your storage goods and for a great many products this is the only way you should be canning. The goal of pressure canning is to achieve the decimation of all microorganism that cause spoilage in food and propagate food born illness. Water boils at 100c which kills the majority of microorganisms and bacteria but botulism can survive temperatures higher than boiling and can thrive in air tight environments. A temperature of 116c (which can only be achieved under pressure) for an extended period ensures anything living is dead. In addition to the above stated loss of flavor and texture many water soluble nutrients are compromised in the process.

The exception to the rule of astronomical heat being necessary to mitigate microbial risk is PH. Harmful microorganisms, botulism included, do not survive in air tight acidic environments. Anything you jar with a PH below 4.6 will not require elongated high heat exposure and most certainly not pressure canning. Some choose, even with this knowledge, to heat pack, meaning to pack your low PH items (tomatoes, tomatillos, pickles, fruit) into jars, lid them, and then boil for an extended period in a water bath (lids above water). I find that even this lower temp boil leaves a lot for wanting in the flavor and texture department and it is not necessary for a proper seal to use this method although almost every instruction will tell you so.

The path of least resistance and most flavor, in my opinion, is to harness the power of PH and use the hot pack method. Tomatoes are an easy first step in this direction as their PH generally sits in the 4.1 - 4.7 range if properly grown in healthy soil so you won’t need to test the PH and can push forth using this method with little concern and a very basic set up. The hot pack method involves filling hot Mason Jars with hot liquid product (or product completely covered by a liquid) placing on the lids, finger tightening the rings, and allowing the pressure from the heat to push out the oxygen inside the jar. The evacuation by way of heat will, when cooling begins, create a vacuum and suck the lid down creating your seal. I will share more recipes in the future involving this method but for now we will keep it simple with tomatoes, a single ingredient that does not require much work to preserve…..

A few points to get started…..

  1. As I always advocate you should know your source, as with any process the product you are using is important, there are a host of bacteria and microorganisms that come along with the logistics of transportation, your canned veg should always be local and organic harvested at peak season and processed as close to harvest as possible.

  2. I always use Ball Canning Jars, I am sure the other cheaper options on the market are fine I have just stuck with theses since the jump and rarely have issues with seals, pay a little more for the industry standard, it will pay off in the end.

  3. Always use new lids, you can reuse rings and jars indefinitely but the lid gaskets are designed for a single seal, save your old lids for items that will hang out in the fridge.

  4. Do not add salt or sugar, tomatoes canned at peak ripeness in season and processed quickly need nothing more, your additives can come when you prepare your dish upon opening, the idea here is to preserve as close to natural flavor as possible.

  5. Do not peel your tomatoes, pretty much every recipe you read or video you watch is going to tell you to do this, its unnecessary and in my opinion draws from the flavor, leave those skins on, they are wonderful and healthy.

  6. Do not wash your tomatoes, again know your source, there should be no reason to wash the tomatoes unless they have been in some place they shouldn’t have been, if they are coming straight from the farm or your garden wipe them clean with a dry towel, the cooking will handle the rest.

  7. Work quickly, work in batches. Don’t try to fill too many jars at once, you want to retain as much heat in the jar as possible before placing on the lid, this will help create pressure to push out air creating a vacuum.

  8. Use tongs for jars and a funnel and ladle to fill. Ball sells a great little kit that includes everything but the ladle, even a magnet for pulling those hard to get lids from the water, invest a little to make your job easier, the tools will last forever.

  9. Work Clean and don’t be afraid to fail, if your seal doesn’t work the first time dump your tomatoes, grab a new lid, and start again, or just fridge whatever jar doesn’t seal and eat them sooner!

Now on to the task at hand…..

  1. Fill Large Pot with Water sufficient to cover and fill empty Mason Jars

  2. Stem Tomatoes, Fill Blender to Max Fill with Tomatoes and Blend

  3. Place remaining Tomatoes in Pot and Cover with Blended Tomatoes

  4. Bring Water to boil and add Mason Jars, each jar should boil for 2 Minutes

  5. Cook Tomatoes until they they are soft, liquid should be bubbling

  6. Drop Tomatoes to Simmer, Pull Mason Jars, Drop Lids in Boiling Water

  7. Fill Mason Jars with Hot Tomato making sure they are covered with Liquid

  8. Wipe Rim of Mason Jar first with a Hot Damp Cloth then a Dry Cloth

  9. Pull Lids from Water, Dry thoroughly, place Lid on Mason Jar, place Ring on Mason Jar and Finger Tighten.

  10. Set Full Jars in a place they will not be disturbed and allow to fully cool before storing in your pantry.

If your pack was successful once the jars have cooled your lids will be popped down, you may even hear them pop if your waiting around to see them cool. A good test once fully cooled is to remove the ring from your jar and pick up the jar by the lid spreading your fingers evenly around the lid to not apply too much pressure in one spot, if you can get it off the table you’ve got a seal. You can store with rings off or just loosely spun on in a cool place and they should hold indefinitely if not disturbed.

Make sure to check your jars at least once a week, just tap the lids and see if they make a ping, if not or if they have pushed back up you seal is lost and you either need to throw out the product or fridge it (if there are no signs of mold or bacterial growth) and make sure to cook very hot before eating, but you shouldn’t face that problem if you have taken care with your canning.

Have fun, ask questions, tell me your results…..


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