Autumn is a perfect time to learn how to can in Southern California. The bounty of summer is quickly fading but there is still time to pick up the end of the stone-fruit and warm-season vegetable harvest and preserve the last of that summer sunshine. Learning how to can now will also enable you to make all of the fantastic pickles that are possible with winter vegetables.
My favourite part of cooking is improvisation. I love to substitute the uncommon for the mundane and I rarely, if ever, measure a thing. However, the practice of canning requires a different approach. The ratios of certain ingredients to the total volume of the recipe are essentially inviolable, particularly acid in pickles and sugar in jam. Additionally, the processing times for the finished, packed jars of food should be carefully monitored. Canning is such a stringent discipline because of a devilish little bacterium known as Clostridium botulinum.
Clostridium botulinum is a ubiquitous (ie. lives everywhere) soil-dwelling, cute-little-cuddlebug of a bacterium that is best known for its capacity to manufacture a neurotoxin called botulin. When a mysterious white powder is found at a post office, this is often the toxin that causes all of the fuss. The temperatures achieved by boiling-water bath canning cannot kill this bacterium. Consumption of the botulin toxin through contaminated food results in botulism, a terrible condition that begins with muscle weakness, progressing to paralysis, respiratory failure, and sometimes death…
So are we ready to make some pickles!?!?!
Let’s all take a deep breath. Botulism is extremely uncommon in spite of the fact that C. botulinum lives everywhere. This is because the bacterium only produces the toxin when it is growing in anaerobic conditions – conditions lacking oxygen (like those that are found in a canning jar). The good news is that Clostridium botulinum only grows and produces the toxin under extremely predictable conditions. If we can food that is very high in sugar or is very acidic, C. botulinum cannot grow and will not produce all those nasty compounds that lead to muscle paralysis, etc. My friends, this is why we stick to the recipe.
Stick to the recipe and life will be good or at least it will continue, complete with fully functioning muscles. If you find yourself unable to add ALL THAT SUGAR to your jam, then skip the boiling-water bath and store yours in the fridge for a few weeks or the freezer for a few months.
Tips for Safe Canning with Boiling-Water Kettles
I’ve tried to summarize the important points of canning here, but it is a good idea to read this USDA document on the process. This guide provides a lengthy description of how to approach this task safely.
We also love this website for recipes and advice! – www.foodinjars.com
Overview of The Boiling-Water Bath Canner
Foods are made shelf-stable by packing in glass jars (such as Mason jars) and boiling the filled and sealed jars in a water bath. A boiling-water bath canner is simply a large pot that comes with a wire rack that allows you to lower jars of food into the water without burning yourself. The rack also serves to keep the jars off of the bottom of the pot. After processing, jars of food are removed from the canner and allowed to cool. The jars will seal as they cool, often with a pleasant “ping”.
Canning kits often come with specialized tools such as funnels for filling jars and tongs for lifting hot jars out of boiling water. Canning kits are available almost everywhere and are quite inexpensive. For smaller batches of two to three jars, a large stockpot can be used so long as it is deep enough to submerge the tops of the jars beneath at least an inch of water. A kitchen towel should be placed inside the pot beneath the jars to keep them from resting directly on the bottom.
Choose the Right Recipe
Only certain foods can be safely preserved with a boiling water bath canner. These are foods that are either high in sugar or high in acid (low pH). The recipe that you choose should explicitly state that is intended for preservation.
Foods that can be canned in a boiling-water bath canner include:
a. Vegetables pickled in an acidic brine (as opposed to fermented pickles)
b. Jams and jellies that are high in sugar
c. Marmalades and some fruit butters
d. Whole fruits preserved in a sugar syrup
Did we mention that you should follow the recipe exactly?
There are ingredients such as small amounts of herbs and spices that may be altered but get some experience before you start playing with recipes. Do not alter (!!!) water, vinegar, sugar, or vegetable/fruit content and do not add oil/fat to your recipe.
Use Appropriate Jars
Mason jars are the only type of container that the USDA approves for home canning. There are three components to a Mason Jar – the glass jar itself, a metal lid with rubber seal, and a metal ring that secures the lid to the jar during processing. The jars and the metal rings are reusable as long as they’re in good condition but new lids are required each time.
We at OurLocaltopia love our Weck jars but the USDA doesn’t think they’re safe for home canning. Weck Jars look are quite attractive on the shelf and make for little waste – the only thing you need to renew between batches of jam is the rubber gasket that seals the jar. We will leave the interpretation of the USDA’s lack of approval to you.
Pack Jars Appropriately
Hot-Packing vs. Raw-Packing
Some recipes such as many vegetable pickles allow for you to pack raw food into jars. Others require you to pre-cook or at least heat the food. Again, just follow the recipe. Filling jars is sometimes easier with a specialized funnel – I like to use a funnel when making jams.
Sterilize Your Jars
Jars should be sterilized before packing them with food if the jars are to be processed in the boiling water bath for less than 10 minutes. If the processing times are longer than 10 minutes then you can skip the sterilization step.
You will need to leave a bit of space between the food and the lid of the jar. This space is referred to as “headspace” and will be given in the recipe.
Warm NEW Lids
Lids for Mason jars should only be used once. The lids have a rubber seal that should be warmed before use. This can be accomplished by simmering the lids in a saucepan for a couple of minutes before use.
Clean Rims and Seal Jars
To ensure a good seal, the rims of jars should be wiped clean after packing. Place pre-warmed lids on the rim of the jar using the lid-lifter tool that came with your canning kit – you can also use your fingers, just be careful not to burn them on the hot lids. Secure the lids with the provided metal rings but don’t over-tighten. Rings should be barely finger-tight.
Process Jars in Boiling-Water Bath
Prepare the Canner/Kettle
The water in the canning kettle should be boiling before the jars are packed with food – the first step in canning food is usually to fill the canner/kettle with water and place it over a high flame. Such a large volume of water tends to take quite some time to come to the boil. The water in the pot should be deep enough to submerge the jars below 1” of boiling water.
Loading the Jars
Jars should be loaded into the already-boiling canner using the provided wire rack. This rack helps to lower the food into the kettle without burning yourself. It also serves to keep the jars from resting on the bottom of the pot.
Timing and Processing
Jars should be processed or boiled for the amount of time recommended in the recipe. The water will temporarily stop boiling after you submerge the jars. Allow the water to come back to the boil BEFORE YOU START THE TIMER.
When processing is complete, use the wire rack and/or tongs to lift the hot jars – they will be very hot! Place them on a towel or cutting board instead of directly on the kitchen counter. Contact with a cold surface may cause the glass jars to crack.
Checking For A Proper Seal
Allow the jars to cool completely before checking for a seal. You will know that a proper seal has been achieved when the lid remains tightly on the jar without the assistance of the metal ring. The center of unsealed Mason jar lids will “pop” up and down with the pressure of a finger – sealed jars remain in the “down” position.
Jars that failed to seal can be kept in the fridge for a few weeks without spoilage. They should not be kept at room temperature.
Storing Your Newly Preserved Food
Sealed canning jars should be stored without the metal rings – removal of the metal rings will allow you to determine if a jar has spoiled and a seal has broken. Rings also tend to rust when left in place.
Your newly canned food should be labeled with the contents and the date and stored in a cool, dark place.
Canning is a fantastic way to preserve some of the produce that your garden or local farmers’ market provides. It is a process that requires some precision and attention to detail but it is well worth the effort. Serving some homemade preserves alongside your carefully curated cheese platter will draw oooohhhs, ahhhhhhhs, and requests for recipes from your guests. As simple as preserves are to make they somehow appear sophisticated on the plate!
And stay tuned to OurLocaltopia for my personal recipe and technique for Pickled Green Beans.
-Jonathan Duffy Davis