Skip to main content

You are here

To Can or Can-Not

by Matt Makowski

Canning

The simple wish to put Mason jars to work has led to a can-do attitude

Pickling was my gateway drug into the somewhat complicated arena of canning. When I bought my first dozen Mason jars, I was left with a bunch on the shelf to collect dust. After figuring out my personal preference for pickle perfection, I progressed to pickling all sorts of veggies. Onions, jalapeños, green beans, habaneros, you name it, and I was prepared to pickle it. But even as my fridge filled with Mason jars of tart and spicy goodies, I wanted to move on to the next level, and put the rest of my Mason jars to work.

What began as a simple Internet search turned into an obsession. People have been preserving food in airtight containers for more than a couple centuries, so I figured the methods and execution would be pretty straightforward. I also didn’t factor in the various methods and importance of following properly vetted recipes. The sheer amount of times I read the word “botulism” was almost enough to scare me away, but after being directed to a number of rational books on the topic that were more informative and relied less on scare tactics, I came back around. Seriously, a trip around the Internet searching for canning advice can be as alarming as plugging the symptoms of the common cold into WebMD.

Boiling CansAfter deciding I could do this without killing myself and anyone I dared have over for dinner, it was time to get started — I just had to resist my usual tendency to tinker with proven recipes. The most important takeaway during the learning curve portion of this foray was to be sure to follow an approved recipe and method for all canning. Temperature is the name of the game here. For safe, preserved food, it’s vital that every nook and cranny of the jars’ contents hit 240 degrees for at least three minutes to kill all botulism spores, which are the hardest ones to kill. The value of following a recipe comes from the fact that tested and approved recipes have been assessed hundreds of times in a lab to ensure botulism spores could not have survived.  The gravity of this testing has even led to a relationship between the USDA and the British Home Office, who have been sharing information and testing recipes in tandem for more than 75 years.

While 240 degrees is the magic number, different foods have different density, different levels of acidity, and different water activity. Like baking, knowing the center of your product is cooked properly is equally important, but unlike baking, you can’t stick a thermometer in the center of a jar to see if you’ve hit the magic number. And taking it a step further, erring on the side of caution and over-processing foods can ruin the finished product. While a ruined jar of sauce is preferable to a bacteria infection, it’s still a waste of time, money, and food — so follow that recipe!

More Than Degrees

The other major factor to assess when canning, is the level of acidity — which is measured on the pH scale. How acidic a food is can largely help determine what microorganisms can grow within. So the level of acidity in your recipe can act as a built-in guideline that lets you know what temperature is necessary to destroy bacteria and make it safe to eat. This is why lemon juice  (which measures between 2.2–2.8 on the pH scale) is often added to recipes, as it can decrease the cooking time and influence the canning method that is necessary. As far as acid levels go, the Food and Drug Administration uses a pH level of 4.6 as the magic number to dictate whether a boiling-water bath canning method can be used, or if it’s necessary to use a pressure cooker.

While there are limitations to going the boiling-water bath method, as it’s reserved for canning strong acid foods, pickled things, fruits (including tomatoes), and jams, a pressure canner is the only way to destroy tough bacteria spores that can grow in jars of low-acid food.  So any plain vegetable, seafood ingredient, or meat that is canned must be done so in a pressure canner. What’s more, a pressure canner is not to be confused with one of a 6-quart pressure saucepan, often referred to as a pressure cooker.  A true pressure canner is a big, heavy piece of cast aluminum that commands about as much space on a stovetop as you can muster in a typical home kitchen, and it comes with a tight fitting screw-down lid. While they can be on the expensive side, they’re built to last forever if you take care of them. The only things that can be damaged are the pressure gauge,  vent pipe, and the sealing rims — though there are some on the market that don’t have sealing gaskets, and just need a little petroleum jelly or olive oil to complete the seal.   

Boiling-Water Baths

If you’re working with a food high in acid, the bath method is far easier to work with — and the danger of some sort of explosion is all but diminished. The bath method deals with the basics of destroying yeast, molds, and bacteria, and the pressure of being submerged drives air out of the container that is naturally present in food tissue and creates a vacuum that seals the jars.

There are really only a couple of things to look for in a vessel to be used as a bath canner. First, it’s got to be deep enough. Second, you need to have some sort of rack that will separate the jar from the base of the vessel — there are jar racks built exclusively for this process, but I’ve also successfully used a vegetable steamer. Having glass jars sit directly on the base, just above the heat source, can damage the jar, and will over-cook the food at the bottom. Big 21- or 33-quart enamel pots like this (also referred to as granite ware) can be found at local hardware stores like Startzman’s Hardware on South Potomac Street, or Shawley’s Olde Country Store in Saint James. Just be sure that you have enough room in the pot for the rack and jars to be covered by at least one-inch of water, and to leave some additional space for the boiling water to bubble, and not slop over the side.

Yielding To The Pressure

Pressure CookingWhen I first got the inclination to can a big batch of vegetable stew, I graduated to the big leagues of pressure canning. I took the plunge on a 21-quart All American pressure canner, which came with a thorough recipe and instruction book, an educational DVD for the reading reluctant, and is emblazoned with not one but two giant warning stickers. Maybe it’s the same primal instinct that cooking over an open flame makes cooking a little dangerous and fun, but those warning stickers made this seem all the more interesting, but also reinforced the importance of following directions.

While the pressure canners made since the 1970s are borderline idiot proof, negligence and neglect can still lead to a horror story. Check your valves to make sure they’re clear before every use. The PSI gauges can occasionally go bad, so it’s recommended to have your gauge checked or replaced yearly — same goes for the gasket seals if your pressure canner uses them. Don’t walk away mid-canning — keep an eye on things during the whole process, as that’s the best way to make sure everything is functioning properly and too much pressure isn’t building up. And lastly, read the manual — cover to cover!

While canning stories typically fill the pages of magazines and newspapers in spring, along with the hopes for a massive yield from the garden, I have no qualms about canning whenever my veggies of choice go on sale at the grocery store and I’ve got a little free time. But make no mistake, this is a passion project. Even if you were to can crops strictly from your own garden, when factoring in the natural resources to grow and maintain those crops, then add in the costs of the equipment, and energy costs (not to mention the time involved), this will not be cheaper than going and buying a store-bought salsa, jar of tomato sauce, or can of soup. Canning is about the gratification of knowing what’s in your food, and the pleasure of serving forth something you made yourself.

 

Homemade Tomato SauceTomato Sauce

Ingredients:
5 pounds of tomatoes (per quart of sauce)
2 tablespoons bottled lemon juice
1 teaspoon salt (optional)
Dried herbs (optional)

Tools:
Large enamel or stainless steel pot (for cooking)
Potato masher
Prepared Ball jars and lids (quart sized)
Pressure cooker, or large lidded pot and riser
Funnel
Tongs for picking up Ball jars.

Wash and quarter the tomatoes and toss any that are bruised or discolored. Place six of the quartered tomatoes in your cooking pot and bring to a boil over medium-high heat. Using a potato masher, crush the tomatoes to release juices and stir constantly. While making sure to prevent burning, add additional tomatoes, in batches, making sure to keep the mixture boiling the entire time, and crushing tomatoes accordingly. Keep stirring until tomatoes are soft and juicy — about 10 minutes after the last batch of tomatoes has been added.

Working in batches, press tomatoes through a fine sieve or food mill to remove skins and seeds. Return mixture to pot and bring to a boil over high heat, stirring frequently. Reduce heat to medium-high and boil until volume is reduced by at least one-third.

Next, add lemon juice, salt, and dried herbs to sterilized Ball jar, then ladle hot tomato sauce in, filling to ½ inch of the top of the jar. Wipe rim, center the lid on the jar, and screw band down until fingertip-tight.

The next part is contingent on how you plan to go about processing the jars. If going the bath method, insert riser into canning vessel, and place jars on top, ensuring they are completely covered with water. Place lid on container, bring to a boil and keep jars in there for 40 minutes. Remove canner lid and wait 5 minutes, remove jars, cool, and store.

If you’re going the pressure cooking route, the All American Pressure Cooker/Canner Instruction & Recipe book says pour 2–3 inches of water into pressure cooker, place rack into water, and insert the filled jars into the pressure cooker. Next, batten down the hatches and make sure the lid is securely tightened, and place over a burner on high. You’ll eventually notice a steady stream of steam coming from the vent pipe. After 10 minutes of steam coming out, place the pressure regulator over the pipe to allow 10 pounds of pressure. Be sure to adjust the heat accordingly. The pressure regulator should only jiggle or rock a few times a minute — if it’s constantly bouncing around, dial the heat down a bit. Once you get to that heating sweet spot, begin the countdown. At 10 pounds of pressure, your sauce will need to process for 15 minutes. When the timer goes off, turn off the heat and make sure the pressure dial gauge drops to zero. Now you can remove the pressure regulator with an oven mitt, and let it all settle for an extra couple minutes. When time’s up, unfasten cover and remove it, raising the farthest edge first to keep escaping steam from scalding your arms and face. Remove jars using tongs, and place on a surface to let cool. When jars have come back down to room temperature, store in a cool, dry area.

Pro Tip:
Dried basil, oregano, rosemary, thyme, and Italian seasoning mixes are excellent seasonings for this sauce, but use those preferred by your family. Add the dried herbs to each jar, rather than trying to season the entire batch of tomatoes. Start with 1 teaspoon per jar — you can always add more when using the sauce. Many families like to add a fresh basil leaf to each jar. This is acceptable, but remember to use only unblemished leaves that have been thoroughly rinsed.

 

Vodka SauceVodka Sauce

Ingredients:
1 quart canned tomatoes
½ cup butter
1 onion (diced)
½ cup vodka
½ pint heavy cream
1 package of pasta cooked according to directions

This is my favorite way to gussy up a basic tomato sauce. First, get the water boiling in a pot to cook pasta according to directions. In a large pan, melt butter over medium heat, and sauté onion until slightly browned. Pour vodka into pan, but be careful, as vodka can ignite when first added, causing a large flame, but is easily blown out. After 10 minutes of cooking off the alcohol, add tomatoes, and cook down for 30 minutes. Now it’s time to add the heavy cream. Some people prefer their sauce a little pinker than others, so adding a bit more it acceptable. Cook for a final 30 minutes, and ladle the pasta of your choice into the pan. Coat evenly, and serve piping hot.

 

Zesty SalsaZesty Salsa

Makes 6 pints
Ingredients:
10 cups chopped, cored peeled tomatoes
5 cups chopped, seeded green bell peppers
5 cups chopped onions
2 ½ cups hot peppers such as serrano or jalapeño (depending on how spicy your family likes it)
2 habaneros (optional)
1 ¼ cups cider vinegar
3 cloves garlic (minced)
2 tablespoons minced cilantro
1 tablespoon salt
a tablespoon hot sauce of your choice (optional)

Tools:
Large enamel or stainless steel pot (for cooking)
Prepared Ball jars and lids (pint sized)
Pressure cooker or large lidded pot and riser
Funnel
Tongs for picking up Ball jars.

Combine tomatoes, green peppers, onions, chili peppers, vinegar, garlic, cilantro, salt, and hot pepper sauce (if using) in cooking pot. Bring mixture to a boil over medium-high heat, stirring constantly. Reduce heat and boil gently for 10 minutes, stirring frequently until slightly thickened.

Ladle hot salsa into hot jars, leaving 1/2 inch headspace. Remove air bubbles and adjust headspace, if necessary, by adding hot salsa. Wipe rim, and center lid on jar. Apply band until it is fingertip tight.

Process jars in a boiling water canner for 15 minutes. Remove jars, cool. Check lids for seal after 24 hours —lid should not flex up and down when center is pressed. Store in a cool, dry place.

For tastiest results, chill before serving.