Canning Tips and Tricks
I’ve compiled a list of tips and tricks I’ve been learning over the past few years canning, and would love to hear about any of yours too!
- Add enough acid (lemon juice or vinegar) to keep the PH of your food at 4.6 or lower – some of today’s tomatoes have low acid content so if you don’t want to add acid, pressure can them instead;
- Leave a half inch of head space about the water in a water bath for pickles, or a quarter inch for jams; too much head space can allow food to discolor, while too little can prevent proper sealing;
- Pickles are crunchier if you preserve them in the refrigerator but last longer if you can them for ten minutes, so its a good idea to refrigerate several jars and can some for later use – try adding a 1/8 tsp/pint calcium chloride to crisp them up;
- Working on a jumbo baking tray eases clean-up;
- You can set up baking trays on the counter on a folded towel to put the processed jars on to cool, then use to transport them for storage;
- To keep fruit flies at bay put out a bowl of apple cider vinegar with a drop or two of dish soap, you’ll be surprised how many find there way there after a day or two
- If you live 1,001 to 3,000 feet above sea level you should increase processing time by 5 minutes (3,000 to 6,000 feet by 10 minutes/6,000 to 8,000 feet by 15 minutes/8,000 to 10,000 feet by 20 minutes);
- If your dishwasher has a sterilizing cycle, use it, but otherwise run them through the dishwasher, then boil them to sterilize;
- Scooping the canning mixture or brine into a big Pyrex measuring cup and pouring directly into jars can be faster than ladling into a wide mouth funnel;
- Deep jumbo frying pans can be great for canning shallow jelly jars, just put a cookie or cake rack on the bottom of the pan first, or layer upside down lids as a nest to set the jars on, and test to make sure you’ll have an inch of water above the tops of jars;
- You can tie up or staple a coffee filter for a spice bag or ball if you don’t have one;
- Don’t forget to add a bit of lemon or vinegar to your tomatoes to reduce the risk of botulism, bearing in mind that many tomato varieties today are less acidic than they were years ago, and we just know better now!
- If your jellies aren’t setting up properly, make your own pectin by placing a cheesecloth sack filled with the fruit parts that have the highest pectin content (peelings, cores, and seeds) into the pan;
- All fruits can be canned without sugar, but look for a no sugar recipe because it does affect the taste and texture; use low sugar or no sugar pectin – see: Canning and Preserving Without Sugar;
- Wear surgeon’s gloves when cutting hot peppers – our hands can cause stinging eyes hours after touching them!
- If you’re not sure how much water you’ll need in the canner, fill it half way, and boil a large pot of water to use to top it up after adding filled jars, leaving an inch or two of space above the jars;
- Reprocess any unsealed jars by moving the contents to a clean jar with a new lid within 24 hours, or adjust head space to 1-1/2 inches and freeze;
- Storing jars upside down saves a lot of clean-up;
- If you have hard water, add 1/2 cup vinegar to your water bath to keep a film from forming on your jars and to make jars with water deposits sparkle;
- Don’t forget to cut a little X in the bottom of your tomatoes before blanching to ease peeling – the less time you blanch the firmer they stay after processed;
- If you garden, grow what you want to preserve, and if you preserve, preserve what you actually eat – if you aren’t chutney people, why preserve it? I grow lots of tomatoes and peppers because I love to make spaghetti sauce or tomato sauce or salsa, but how many jars of mustard relish or plum chutney will we really go through in a year? And yes, one zucchini plant is enough! I won’t even get started on some of the horrible zucchini canning recipes I’ve tried…
- To test jam for readiness, drop a tablespoon of boiling jam onto a plate and let it cool. Slant the plate. If the jam doesn’t slide, it’s ready. If it slides easily, continue cooking;
- To swap powdered pectin for liquid pectin, use two tablespoons of powdered regular pectin for every packet of liquid pectin, but instead of adding the pectin at the end of cooking like you do with liquid, whisk the powdered pectin into the sugar before you combine it with the fruit;
- Pretty up your jars by adding a few pinked banana pepper rings or pieces cut into shapes with a vegetable shape cutter to pickles or a little curl of lemon zest to a can of peaches – not enough to spoil or drastically change the flavor, but enough to personalize your canning;
- Use a thermometer in your lids’ simmering water to keep them 180 degrees or under, as overheating lids can result in failure to seal;
- If you don’t like your lids sliding away from you in the simmering water, put them in a lid rack;
- If a ring won’t come off a jar, cover it with a hot cloth for a minute or two;
- Once your jars have sealed, remove the rings, you don’t need them for storage, so if they are unblemished and undented, you might as well reuse them this year;
- If you get experimental, label the jars with a batch number to recognize those jars when tasting later, and note the variation on a sticky note in your recipe book so you know whether to try it again next year;
- Fruits high in pectin, like blueberries, will bounce on a table, so that can be a guide if you’re not sure how much pectin to add;
- When cold packing things like cucumbers or beans for pickling, avoid adding boiling hot brine to prevent jar breakage;
- 10-12 almonds thrown into a pot of jam fruit are enough to season a batch;
- If you have extra space in your canner fill it with jars of water and to store and use as bottled water if you need emergency water supplies;
- Sterilize an extra jar in a size or two smaller than your batch in case you have just enough for a smaller size;
- Don’t start your processing timer until the water boils again;
- To keep the kitchen cooler, place lids on any pots of water whenever possible;
- Dress comfortably, invite your Mom or sister or best friend to help, plan a hearty lunch and take-out dinner, and crank up the A/C on canning days!
One pound of tomatoes equals:
- Two whole 3-inch tomatoes
- Three 2 1/2-inch tomatoes
- Four or five 2-inch tomatoes
- About 2 1/2 cups chopped
- About 3 cups quartered
- About 2 cups puréed
Things Not to Do
- More so even than when baking, its important to use exactly as called for in a recipe, unless you know how to keep the PH balance for proper preservation;
- Don’t ever preserve in the oven;
- Don’t add a lot of extra herbs and spices, as they can add bacteria, and many herbs turn black when processed and can even turn our produce nasty colors;
- Powdered or dried herbs will make a brine cloudy;
- Don’t add low acid ingredients like onions, celery, peppers, garlic, if using a water bath canner;
- As a general rule, don’t can more produce than you can use or give away in a year, because, while canned food stored in a cool, dark space can last for many years, you can’t always see the effects when it is no longer edible;
- Don’t use butter or fat, as they can cause spoilage;
- Don’t use recipes prior to 1990 – acidity levels have changed in some vegetables over the decades, especially in popular new low-acid hybrids, and scientists have come to know more about preserving food, so using newer recipes is always a good idea (see recipe books below);
- Don’t substitute an inverted plate for a canning rack – the water has to circulate under the jars too;
- Don’t use thickeners other than those recommended for jams or jellies (no flour, pastas/grains or starches);
- Don’t eat any canning that is discolored or has an odor;
- Try not to stock up too much on lids, they only have a shelf life of five years;
- Avoid using metal utensils inside glass jars to prevent scratching or breaking them;
- Pressure canners must vent for ten minutes before sealing – never rush a pressure canner;
- Don’t use leftover mayonnaise jars or spaghetti sauce jars if you want to preserve, only use if you have sterilized them and plan to keep in the refrigerator or freezer;
- Don’t substitute seasoned salt, sea salt or table salt for coarse salt in recipes, as additives can add unpleasant flavors;
- Don’t leave the traditional style canning rack inside the canner overnight or it will rust (invest in a new stainless steel or silicone one if that happens);
Inspect each jar prior to use for signs of spoilage, and discard any food that you are unsure about.
Failure to seal, or unsealing during storage due to
- nicks or chips in the rim of the jar – slightly damaged jars can be used when storing pickles in the refrigerator where no seal is required;
- lifting with the ring instead of using a jar lifter;
- rim of jar wasn’t wiped well enough before applying lid and ring – keep a fresh supply of clean hot cloths or dish towels for this task;
- overheating the lids – keep them at 180 degrees or less;
- inverting jars;
- using old lids (try to use them up within a year or two);
- over processing or failure to process;
- improper tightening of rings;
Food is dark at the top of the jar due to
- not enough liquid covering the jar – make sure food is covered with liquid;
- air in the jar permitting oxidation (either bubbles weren’t removed or too much head space was left) – always run a spatula or plastic knife around the jar to remove bubbles and leave appropriate head space (1/2 inch for pickles, 1/4 inch for jams);
- food not processed long enough to destroy enzymes – follow recommended time after water comes to a boil again.
- weak brine or vinegar – it needs at least 5% acidity, and use pure pickling or canning salt;
- failure to remove the blossom end – cut 1/16th inch off the blossom end before pickling;
- insufficient liquid – keep them covered; if the cucumbers are too big put them in a bigger jar or slide them, but don’t leave them above the top of the brine;
- failure to remove scum daily from the brine during the brining process;
- lids not applied quickly enough – cap pickle jars one at a time rather than filling all jars and then applying lids and rings;
- under processing;
Dark colored pickles due to
- the minerals in hard water;
- using metal utensils to make your pickles;
- using ground spices instead of whole;
- leaving whole spices in the jars – whole cloves, cinnamon sticks and other spices should be removed before canning;
Green vegetables turn brown due to
- overcooking during preprocessing;
- vegetables that are overripe – use vegetables at their peak of ripeness for canning;
Spoiled contents due to
- poor seal;
- processing for the wrong time;
- using the wrong pressure;
- spoiled food – watch food carefully for blemishes or rot;
Cloudy jar contents due to
- spoilage, either due to improper processing or storage – discard;
- minerals in the water – if your water is quite hard, use bottled water;
- additives – either in salt, spices or herbs;
- starch in vegetables – don’t use overripe vegetables;
Liquid disappears during canning due to
- failure to remove air bubbles;
- not enough head space;
- using the cold pack method instead of hot pack;
- packing too loosely;
- depressurizing pressure canner too quickly;
- fluctuating pressure – it is important to maintain even pressure;
- failure to cover jars with 1-2 inches of water in the water bath;
- starchy foods absorbing the liquid.
- fruit lighter than the syrup – use ripe firm fruit and a light or medium syrup (if using fruit from your own trees you will get to know how heavy a syrup you can use);
- over processing – watch your time when processing or enzymes will be destroyed;
- packing loosely – pack as tightly as you can while still allowing removal of air bubbles;
Brown corn due to
- using old corn – use freshly picked milky corn;
- not enough liquid – make sure the corn is covered;
- processed at too high a temperature;
Canned juice with poor flavor due to
- immature or overripe fruit – use good tasting fruit at the peak of ripeness;
- using too much water – follow the recipe (no water is necessary for tomato juice);
- improper storage;
Stiff jelly due to
- too much natural or added pectin – use ripe fruit;
- over cooking;
- too little sugar – follow the recipe;
Soft jelly due to
- wrong amount of sugar or liquid – follow the recipe;
- too large a batch – its best not to double jelly recipes;
Jelly with glass like particles due to
- too much sugar – follow the recipe;
- under cooking, resulting in sugar not dissolving completely and consequently failing to mix with the fruit;
- over cooking or cooking too slowly, allowing the fruit water content to evaporate;
- undissolved sugar stuck to the pan may have fallen into the jelly when pouring – make sure you wipe the sides down well on the pot when cooking;
- in grape jelly it could be tartaric acid, a natural substance – allow grape juice to settle, and ladle carefully, avoiding sediment, and strain through several layers of cheesecloth;
Shrivelled pickles due to
- too much salt, vinegar or sugar added at once – add the recommended amount gradually;
- whole cucumbers were not pricked – prick your cucumbers to allow the brine to saturate them;
- cucumbers with a wax coating were used;
This is caused by faulty growth. You can identify them by the cucumbers that rise to the surface when you are washing them. These are best used for relish.
Green vegetables lose their bright color
This is caused by chlorophyll, the substance that makes green plants green, breaking down in the heat. I was quite disappointed the first tine I boiled purple beans, only to see them turn a rather unattractive shade of green.
Mold in jelly
This is caused by improper sealing.
This is caused by an enzymatic change while handling the tomatoes after they have been cut. To prevent separation, heat the tomatoes quickly to a simmering temperature, adding tomatoes to the pan one at a time as you cut them rather than cutting them all, then heating the pan. If it does happen, flipping the jars over after they’ve cooled can help remix.
This is harmless as long as there is no sign of food spoilage and no holes in the lid. It is the result of compounds in the food causing a deposit on the underside of the lid due to imperfections in the enamel coating, allowing a reaction with the metal on the lid.
- Fill your canner halfway for pint jars, or enough to leave an inch or two over the top of higher jars, with clean water.
- Warm jars in the oven, and gently simmer the rings and lids while preparing food.
- Fill hot jars with hot cooked food or with fresh produce covered in hot brine, carefully wiping rims, before adding lids and rings, tightening just until you feel resistance (never fill cold jars with hot food, or hot jars with cold food). You’ll develop your own rhythm for this process, either filling all the jars, then wiping, then lids/rings, or doing one at a time – this is when assembly line is nice if you have helper(s). I prefer to do one jar at a time.
- Load filled jars into the canner rack and lower the rack into the water, or if you’re nervous about lowering the rack, leave it at the bottom and place one jar at a time using a jar lifter. Keep jars upright at all times.
- Add enough boiling water to cover the jars by at least an inch or two, depending on processing time, adding more later if necessary.
- Turn heat to its highest position, cover the canner, and bring water to a vigorous boil again, then reset heat to maintain a steady boil.
- Set a timer for the total minutes required for processing.
- When time is complete, turn off the heat and remove the canner lid. Wait 5 minutes before removing jars.
- Using a jar lifter, remove the jars and place them on a towel to cool, leaving a bit of space between the jars during cooling. Let jars sit undisturbed to cool at room temperature for 12 to 24 hours.
- Check to make sure the tops have all sealed by applying gentle pressure on each lid. The lid should be curved downward and should not move when pressed gently with a finger. Tapping the centre with a spoon will make a pinging sound. If any make a popping sound or show resistance, either reprocess those within 24 hours of initial processing, or reduce volume to allow 1-1/2 inch head space for freezing, or refrigerate and use before spoiling. It can take several hours for a jar to seal, so leave them overnight before giving up.
You can start out as simply as having a few mason jars with lids and rings, and a rack in the bottom of a pot big enough to cover the jars with an inch or two of water. But if you are going to can even a few batches, you’ll probably want to invest in at least a water bath and a jar lifter. Most home canners end up with most of the following items, excluding the pressure canner if they don’t can low acid vegetables or meat:
- Water bath canner with rack (for use with high acid foods like pickles, tomatoes, relishes, jams, jellies);
- Pressure canner if you’re going to can low acid vegetables or meats;
- Kitchen scale;
- Dutch oven or large pot;
- Colander, sieve, food mill, jelly bag, cheesecloth;
- Wide-mouth funnel and ladle, Pyrex measuring cup;
- Rubber scraper or plastic knife to release air bubbles after filling jars;
- Assortment of jars, lids and rings;
- Lid lifter and jar lifter;
- Clean cloths;
- Kitchen timer (or use an oven timer or microwave timer);
- Trivets, wire racks;
Popular Canning Recipe Books
- Preserves (Company’s Coming)
- Ball Complete Book of Home Preserving
- Canning for a New Generation: Bold, Fresh Flavors for the Modern Pantry
- Food in Jars: Preserving in Small Batches Year-Round