The Art of Canning

August 20, 2015

It’s that time of year. Your seeds have sprung into full-grown plants laden with the fruits of your labor. While much of your garden bounty ends up on your table–and friends,’ neighbors’ and loved ones’ tables, there are often an excess of fruits and veggies that can overwhelm you. There are only so many tomatoes, zucchini or berries you can eat. You can’t imagine wasting this food, so what are you to do?

You can freeze foods, to be sure, but then there’s the art of canning, which I love!

Growing up in an Italian household, our garden was designed for excess so that my mother and grandmother (and aunts and cousins…) could preserve the abundance for the winter months to come. It’s a wonderful way to store your veggies and fruit while they are in season, creating a whole new bounty of food once winter sets in.

There are two types of canning: water baths and pressure cooking. Both methods heat the food, killing any microorganisms that could cause spoilage while creating a vacuum seal in the jar, making it shelf stable. Yes, you lose some enzymes in this process but there are so many advantages to canning, that it’s worth it:
You save money.
It’s eco-friendly.
You don’t waste food.
It’s fresher than commercially canned food and tastes better.
You know what’s in it: no additives like BPA or preservatives. 

This primer is for water baths as pressure canning is often used for meats. I also think water baths are easier to manage and a bit safer in your kitchen, but that’s me.

Stuff You Need
In order to preserve food well, you will need the following equipment:
Canning Jars and Sealing Lids— I use mason-style jars with sealed lids and rings, which can be found at most grocery stores or kitchen shops.
Ladle— To fill jars
Large Pot — Huge! I use an old lobster cooking pot (Remember those? The black pots with white dots on them?) to boil the jars holding preserves and jams, fruits, tomatoes, pickled vegetables–whatever you are canning.
Tongs — Use rubberized tongs to remove jars from their water bath as they can become quite slippery–and you want to be safe and not get scalded. Some people use magnetic “lifters,” but I prefer tongs. I feel they are more secure and I have more control.
Clean Dish Cloths — Used to wipe down jars, lids and rims of jars

Optional Stuff:
Wide-Mouth Funnel — This can make filling jars with sauces or jams easier and less messy, but honestly, I don’t use one.
Lid Wand — Some people like these for easy removal of lids and rings from boiling water, but I use tongs.

The Process
Here we go…

1. Sterilize Your Jars
Wash the lids, seals and jars in hot soapy water. Move them to a boiling water bath for 10 minutes to sterilize. Remove the jars carefully from the water with tongs, but leave the lids in the hot water until you’re ready to use them to ensure they don’t come in contact with anything before you seal your jars. Stand the jars on a cloth-covered surface, open-side down until ready to fill so they drain and stay clean.

2. Prep the Food
For the best flavors, can your fruits and vegetables right after you harvest them. This way, you get the most bang for your nutritional buck.

Prepare fruits and vegetables by washing them well. Dirt will ruin the whole batch.

Slice and dice; peel as needed. For instance, tomatoes should be blanched and peeled before canning, even if you are canning them whole. Peaches, pears, apple, apricots can be peeled or not, left whole or sliced. Carrots, zucchini and cucumbers are not peeled and can be whole or cut. There are a couple of recipes for various canned foods at the end of this article or search online for some yummy recipes to use.

Iron, aluminum and copper should not be used when preparing your fruits and vegetables to can as they can cause discoloration of the produce.

3. Fill the Jars
Filling your jars sounds simple, right? It is, but a couple of guidelines before you dive in.

A. Don’t fill the jars to the tippy top. Produce and the liquid you may add will expand during the boiling process, so leave about ½-inch at the top of each jar so they don’t crack and leak while cooking. I usually fill my jars right to the bottom of the rim of the jar. 

B. After filling your jar with veggies or fruit, (unless you’re canning jams, jellies or preserves), you’ll be pouring hot liquid to cover the ingredients in the jar. Be sure your liquid covers your produce completely.

C. Make sure there are no air bubbles along the sides of the jar and that your food is submerged in the liquid. I shake the jars lightly (back and forth), holding them with a clean cloth (since they ‘re hot) which causes any air bubbles to rise to the top and pop.

D. Wipe the rims of the jars down with a clean cloth before laying the sealing lids on top. Be sure the sealing lid sets correctly on top of the jar or it won’t seal when processed. Screw the cap on tightly.

4. Process the Jars
Preheat water in your very large pot, but not to boiling. This will prevent the jars from cracking when you put them in the water. Carefully add the jars using tongs. Try to keep the jars standing up in the pot. The jars should not touch, if possible, as this increases the likelihood of cracking.

Water should be an inch or two above the top of the jars when they are placed in the pot for a water boiling process so you will likely need to add water after the jars are in the pot. It’s essential that the jars are completely submerged under water.

Bring the water to a slow boil with the pot covered and once it boils, start your timer to process for the length of time dictated by which vegetable you’re canning. (This varies with altitude so you may need to adjust based on where you live.)

5. Remove the Jars and Allow Them to Cool
When the time is up, carefully remove the jars from the boiling water using tongs. Place them on a flat surface covered with a dry towel (to prevent cracking as they cool). Let them stand undisturbed until completely cool. As they cool, each lid will make a popping noise as the vacuum seals. You will notice the lids will dent slightly inward.

After they have cooled completely, press down on the center of your jars to ensure they have sealed completely. Any lids that spring back have not sealed and therefore are not shelf-stable. Just pop them in the fridge and enjoy them first.

6. Store Your Food
Some people like to label their jars with the contents and the date. I don’t worry about this because I know what I canned and I usually only preserve what I will use in a year. I can fresh every year, but that is up to you. I will say that it can be pretty to get cute little labels and identify your jars, especially if you might give them as gifts.

Finally, store your precious preserved food in a cool, dry dark place. We store our bounty on shelves in the basement. I love looking at my filled shelves!

I know this seems like a lot of steps, but it’s not really complicated. The most important thing is to keep the jars clean. And then have fun!


Whole Tomatoes
A 25-pound box of plum tomatoes will make about 12-14 quarts of tomatoes. It will take you about 5 hours to complete the process, but if that’s too big a chunk of time, try doing 4 jars a night for 3 nights in a row.

25 lbs. San Marzano plum tomatoes
Fresh lemon juice
Sea salt
Fresh basil (optional)

After sterilizing the jars (see above), place them open-side down on a cloth-covered surface. Spoon 2 tablespoons of lemon juice into each jar with a pinch of sea salt and 1-2 fresh basil leaves.

Bring a pot of water to a boil. Cut the core out of the top and cut a shallow cross in the bottom of each tomato. This will make it easier to peel them after blanching.

Drop tomatoes into boiling water for 1-2 minutes. Don’t crowd the pot or they will take forever to blanche. Remove the tomatoes carefully from the water and transfer to a bowl of ice cold water. Allow the water to return to the boil before blanching more tomatoes. When the tomatoes are cool enough to touch, peel the skins off.

Push the tomatoes into the jars. (I do this as I peel them to save on messiness.) About 4-6 will usually fill a standard quart jar. Push them in with a wooden spoon. It’s okay to crush them a bit.

Wipe the rims and jars with a clean cloth. Any tomatoes on the rim can inhibit the seal. Place the seal lid on top and screw the lid (band) on tightly. Repeat until all your jars are filled and sealed.

Place in a pot of hot water and add water as needed to submerge the jars completely. Cook for 45 minutes. Carefully remove the jars and transfer them to a cloth-covered surface to cool. Repeat with remaining jars as needed to cook them all. Allow to cool completely, carefully listening for the popping of the lids to prove they have sealed.

Cook’s Tip: To preserve tomato sauce, simply make a big batch of your favorite recipe. Sterilize your jars and lids. Fill the jars to the bottoms of the rims. Seal tightly and submerge in a boiling water bath as described above and cook for 45 minutes after the jars reach a boil. Cool completely and store as you would any preserves.


Strawberry or Blueberry Preserves
When I was a kid, we made berry preserves every summer. I hated the process as we sealed the jars with paraffin wax. Those days are over. It’s so simple and easy now and the results are heavenly.

Makes about 6-7 pints

6 pounds strawberries and/or blueberries, (local/organic if you can)
3 ¾ cup brown rice syrup
1 ½ unpeeled apples, grated (for the pectin)
1 ½ tablespoons lemon juice

Wash pint jars and lids in hot soapy water and rinse well.

Make the jam: Rinse the berries and be sure to remove any spoiled or severely blemished ones. Remove the green stems off strawberries and slice in half. With blueberries, remove any stems.

Add the berries, syrup, grated apple, and lemon juice to a large pot over high heat. When the mixture boils, reduce the heat to medium and allow the mixture to continue to boil lightly for about 40 – 60 minutes. The berries will burst and thicken so stir often, scraping the side of the pot as it cooks. Note that the longer the jam cooks the thicker the final product will be but it will never be quite as thick as store-bought preserves.

Mash the fruit with a potato masher or fork once the fruit begins to soften. If foam forms on top of the fruit, just stir it in.

Meanwhile fill the canning pot ¾ full with water, cover, and bring to a boil over high heat. Boil your jars, lids and seals for 10 minutes. Carefully transfer the jars to a cloth-covered surface, leaving the lids in the boiling water.

When the jam is done cooking, taste it to make sure the flavor is to your liking. To test for texture, drop dots of jam on a cold refrigerated plate. If the preserves seem to set up, you’re good to go. You can also see if it coats the back of a spoon. Both of these methods indicate that your jam will have a lovely thick texture.

Ladle the jam into the jars leaving ¼ inch headspace at the top of each one. If there are any air bubbles, slide a clean knife along the inside of the jar to remove them. Use a clean rag to wipe excess off the outside of the jar and rim.

Set the seal on top of the jar squarely and screw the lid on tightly. Repeat until all jars are filled.

You can stop here and refrigerate your jam for 3-4 weeks, if you choose.

To process the jars for longer storage: Bring the large pot of water back to a boil. Place a dish towel or canning rack on the bottom of the pot so the jars do not directly hit the bottom of the pan. Carefully lower as many jars as will fit without overcrowding into the boiling water so they are covered by at least 1 – 2 inches of water. From the moment the water is boiling and the entire first batch of jars are submerged set the timer and process them for 10 minutes.

When the time is up, use tongs to carefully remove the jars from the water. Put them on a cloth-covered counter and don’t move them. You will hear your jar lids popping which means they’re sealing properly. If jars aren’t sealed within 12 hours, move them to the fridge and eat within a couple of weeks.


Finally, remove the bands from sealed jars and with a clean, wet cloth wipe off any jam that may have leaked and congealed on the outside rim of the jar. This will prevent mold from forming on the band. Re-apply the band snugly. Label your jars and store in a cool, dry, dark place for up to one year.