Let’s talk canning basics: Boiling Water Bath Canners! :)

Now let’s look at Boiling Water Bath Canning specifically, and in more detail.

With the exception of official canning jars, new lids, and solid rings … the only other thing you really need to do BWB canning is a deep pot. Of course, you can buy dedicated BWB canning pots, and they are well-designed for the purpose. Most are thin-walled, lidded enameled pots that can heat up extra fast. Many are almost wider than they are tall (especially in the larger sizes) in order to handle a lot more jars. Some also include a basket-type insert inside that you can use to lower/lift jars, baskets that are often designed to hold jars in place–and separate, so they don’t bang together–as they boil and process.

Official canning pots are nice to have. Bought as part of a set, they can often give you all the canner pot parts in one neat package, but they can also run you anywhere from $20.00-100.00, depending on how plain or fancy they’re made and/or accessorized. However, if you’re like me … you tend to avoid unitaskers in your crowded kitchen! That’s easy in this case: any large pot in your kitchen can be transformed into a BWB canner pot, as long as you remember to take a couple of things into consideration:

  1. You need a pot that’s tall enough, such that–once you put your jars inside–you can add enough water into the pot with them to bring the level of the water in the canner pot up to at least two (2) inches over the top of the jars. Three (3) inches is even better.
  2. Most modern canning pots, BWB or Pressure Canning, use a round metal rack in the bottom of the pot that looks something like this one. It’s basically a slightly raised (one-half inch) metal platform, slightly smaller than the diameter of the bottom of the pot. It’s strong and solid enough to hold your jars off the bottom of the pot, but it also has holes in it that allow the water to flow under and around the platform … which helps insulate the jars from the direct heat that you apply to the bottom of the pot. Other canning pots use a metal basket inside them, one which serves two purposes: it allows you to lift and lower jars, yes … but it also serves as a vented metal spacer to keep your jar bottoms from making too much direct contact with the amazingly hot bottom of your soup pot, plus it serves as a way to let water circulate under the jars. So–if you don’t necessarily want to buy a dedicated BWB pot–you need to find something metal that serves the same purpose as either the rack or basket configuration. Look around your kitchen, and use your imagination. It needs to cover most of the space on the bottom of the pot. It needs to be big/strong/heavy enough to keep the bottoms of the jars from touching the metal bottom of the pot, but it also needs to be vented and raised up enough that water can mostly flow freely underneath the bottoms of the jars. This is VERY important. If you let the bottoms of your jars touch the metal bottom of your BWB canner pot without that cushion of water between them, then your jars of Aunt Tillie’s Famous Rubarb and Fennel Chutney will more than likely EXPLODE all over the inside of your canner pot. In case you were wondering, that would be bad :)

Good non-dedicated BWB canner pot substitutes include any large, tall soup pot … though, personally, I use a tamale steamer. Tamale steamers are thin metal just like an enameled canner pot, so they heat fast. They also tend to be tall–which is advantageous in getting your water deep enough–plus they have a removable steamer shelf already build into them that will keep the bottom of your jars several inches above the heat source. They also come in a wide variety of sizes to cover a wide variety of BWB plans. I bought mine at a cheap box store: K-Mart, I think. If you can’t find one in the regular retail chains in your area, check tiendas (Mexican grocery stores) as well. You can often find good deals on them there, too. Mine is a 42-quart, and I got it on sale for just under $30.00. I’ve seen them as small as 10-quart, and as large as 60-quart size.

If you decide not to buy a tamale steamer, just use a tall pot and find something to use as your vented metal spacer in the bottom of the pot. If you don’t want to buy an official replacement rack for a canner, one that’s slightly smaller than the bottom of your soup pot, then look for things like metal divots sold as burner covers or hot pads. Anything like that will work, as long as it’s wide enough to keep the jars off the bottom of the pot, and it has holes in it/some configuration that allow the hot water to circulate under/around/through it. Alternately, you can use a standard steamer basket/tray that fits down flat inside your pot, or any sort of wire basket, as long as it’s mostly flat … so that you jars won’t tip over as they boil. I also used a silicone muffin pan in the bottom of a pot once, turned open side up. I didn’t have many jars to process in that batch (I think I had four), and it worked for me to just sort of set my jars down in four individual muffin cups, and then to lean each one out toward the edge of the pot. Be creative :)

As additional equipment, I also keep one of those scissor-type jar lifter tools (like this one: Back to Basics Jar Lifter), a long-handled parts magnet, and a pair of VERY long-handled kitchen or BBQ tongs handy when I’m working with a BWB canner. These things will help you save burned fingers when working with boiling water and scalding hot jars.

Now that you have your equipment together, let’s talk about the science of BWB canning in more detail.

If you look at most of the information/charts you can find (online and otherwise) that list processing times and recommended methods for the various types of food one might decide to put in sealed jars for long-term storage, you’ll notice that your recommended sterilizing cycle in a BWB is almost always shorter in duration than a standard Pressure Canner cycle. BWB canning cycles tend to run from five to thirty minutes–occasionally longer–when most Pressure Canner cycles can run that low … but most run 30 minutes, 60 minutes, 90 minutes, or even more at one stretch. As I also mentioned, the temperature inside a BWB doesn’t get as hot overall as what you can achieve in a pressure canner. The water in a BWB (and everything else in the canner) can only reach the point of boiling (whatever that temperature is at your elevation: 212 degrees at sea level), but it can’t get hotter than that … no matter how long you keep heating it.

This combo of facts means that–between the two canning choices–you don’t nearly get the same level of overall sterilization with a BWB that you can achieve with a Pressure Canner.

However, there are lots of ways to insure that you’ve battled the dreaded canning cooties adequately, long before you do your BWB cycle. For example, in the recipes for many BWB-type foods, they ask you to bring your food up to a good rolling boil at least once during the preparation stage, one you can’t easily stir down. That’s usually enough to kill most food-born bacteria in acidic foods.

Granted, a good rolling boil isn’t 100% necessary for all BWB products either. We do raw-pack some fruits, and they still have excellent longevity that way. However, in most cases … you should bring your cooked jams/jellies/pickles/relishes to a good, hard boil at least once before putting them into your jars. That one step could help increase the longevity of your canned foods by as much as two-fold.

Clean equipment is also very important to the long-term success of your home-canned BWB goodies, even more-so than when you’re Pressure Canning. Learn how to clean your gear properly–and then how to keep it clean–before, during and after using your BWB!

The recommendations from the various canning authorities usually say you should boil your equipment for either ten or fifteen minutes in order to sterilize it. Personally, I tend to go with more like 15-20 … just in case. It’s only boiling time, after all. I can spend that in front of a movie if I have nothing better to do :)

Sterilizing your flat, rubber gasketed lids  is a second-stage job, so when you’re assembling your canning gear … set your rubber-gasketed lids aside in the very beginning.

To sterilize your empty jars, rings, canning funnels, ladles, and everything else you plan to touch your food with (like I said … except your rubber-gasketed lids: We’ll discuss those in a minute, separately), first put everything into your BWB Canner pot. Put that pot on the stove. Add enough water to cover the tallest item by at least three inches. Turn the heat on HIGH. Bring the contents of the pot to a boil … and, once the water is boiling hard … THEN set your timer for 15-20 minutes.

In other words, don’t start the timer before your entire pot of water water is absolutely at a FULL, ROLLING BOIL … or you won’t get the optimum sterilization possible.  From there, let the pot boil hard for the entire 15-20 minute duration without reducing the heat off of high. That’s the only way to ensure that your jars are as absolutely sterile as you can possibly get them in a home kitchen before you start.

Note: Given the high level of water in most boiling water baths, this step can sometimes cause boiling water to spit and sputter water all over your kitchen. Be careful and don’t get burned! I’ve found that a tight-fitting lid is a must on your BWB pot. Bonus points: it helps your water boil faster, too!

The traditional method for sterilizing jars (the one my family taught me) was to take all of the hot jars and rings out of the BWB once the timer goes off, and then to arrange them nearby on a kitchen towel or some other absorbent sheeting, all open-side down to drain. Many people also leave their jars to rest in a warm (200 degree) oven until they’re ready to use them, only removing one or two at at time as they’re filling them.

That works, but it allows your jars to cool too much sometimes, too … which is potentially problematic. Large temperature differences could cause jars to break either when you add the food, or when they’re processing inside the canner. Plus–with those jars lip-down like that on a kitchen towel/paper towel/whatever … no matter how clean you think the surface is–you’re increasing the chances that you may transfer new bacteria right back onto your nicely sterilized jars, thanks to whatever you sat them down on. That would be silly after all your hard work!

That’s why … when I’m not trying to work with a huge amount of jars at the same time–say, less than a dozen–I often just turn the heat off and leave my jars in the BWB until I start to fill them. More on that in a second :)

I said we’d cover it in a minute: and you’re right … this need for extensive sterilization during a BWB canning cycle also means boiling and sterilizing your rubber-gasketed lids as well. It sounds like it should be a simple-enough process (learning how to boil jars was easy), but please be very careful doing it. Tradition had us putting those flat, rubberized lids into a separate pan, where we boiled them 10 minutes, or 20 minutes … basically into oblivion. However, overboiling (like with the oblivion method) can age the rubber portion of the lid drastically, and create a seal that may seal just fine initially … it just may not stay sealed for long. That means you could lose all your good food and hard work. Not good! This is the first hurdle we have with gasketed lids.

Secondly, unlike canning jar rings–which can be used and reused many times (as long as they’re not too rusty, they’re fine)–when it comes to the flat, rubber-gasketed portion of a standard two-part canning lid … you should always start with a clean, new lid on each and every jar of food you can, one that’s never been sealed before. This means that–right out of the box–they’re usually not very dirty overall, so a quick 1-2 minute dip in boiling (212 degree) water should rinse off/kill most canning cooties … and the rest shouldn’t survive beyond the acid in the jar and the additional heat and duration of the BWB, especially if you’re talking about something that processes more than 10 minutes or so. That initial application of heat also starts the rubber gasket melting ever-so slightly, an important component of building a good seal on a canning jar, without boiling the rubber on the lid so much that it starts to fall apart on you.

You can use a separate pot of boiling water to heat-treat your flat lids, but I tend to just use my BWB pot where I’ve boiled the rest of my tools. The depth of a BWB presents problems retrieving small things from the bottom of the pot, so you have to have long-handled tools. I personally use a long-handled parts magnet I found in a Harbor Freight (hardware and tool) store for all my lid handling. See my Blonde Chutney video for a picture of it. My parts magnet is about two and a half feet long: a somewhat weak magnet on the end of a flexible spring. It’s perfect to dip and retrieve rubber-gasketed lids and metal canning rings out of deep boiling water, but not so strong (don’t buy an expensive one) that I have to worry about it picking up more than one lid at a time. I paid $1.00 each for mine.

When I’m ready to put food into jars to put into my BWB, I first turn the heat under my BWB pot back up to high, and raise the temperature of the water around the waiting jars back up to something close to boiling. Once it gets hot enough–and I’m ready to start filling jars–I drop two flat gasketed lids into the waiting BWB pot. Then I use sort of a swap method as I go. I pull out an individual sterilized jar–long tongs are your friend–then I drain it and fill it with hot food. Clean the lip, then fish out one flat lid and one ring out of the BWB pot with the magnet. Top the jar with the two-part lid and tighten, and then take a moment to add another flat rubber-gasketed lid to the boiling water. Be sure to keep up with which lid has been in the water longer, so you can take them in order.

Once my filled jar is filled to within proper headspace and then closed finger-tight, I wipe the outside of the jar carefully (so as to not contaminate the water in the BWB), and then I drop the filled jar right back into the pot with the rest of the empty jars.

Repeat until all the jars are filled and back in the BWB hot tub for their final boil. As you drop in the last jar, turn your heat back on high. Remember, don’t start your timer until you have a rapid boil in your pot!

Once your timer goes off, turn the heat off under the pot … but DO NOT TRY TO MOVE IT OFF THE STOVE! A canner pot filled with jars, food, and water can be incredibly heavy, and as water sloshes … it can throw off the balance of the pot of boiling water in your hands, and pour it right down the front of you. Be smart! Let the active boiling come to a stop in the pot first, and then use long-handled tools to carefully remove the jars. I’ve also found that a long-handled Asian dipper is a very smart canning assistant. It allows you to safely dip a large amount of water (mine’s a quart) out of a hot pot … while the rest of you is safely 3′ away. If you can’t find a long-handled Asian dipper, use a large Pyrex measuring cup instead. Either can help you lower the level of the water in your BWB quickly and safely, allowing you easier access to your jars in ways that will hopefully keep you from burning yourself.

Once your water level is down enough that you can safely reach the jars with your jar lifter or tongs, remove each jar and allow it to rest/cool unmolested until they’re sealed and room temperature. If you have a jar(s) that don’t seal, don’t fear … just put them in your refrigerator and eat them first.


So let’s recap:

  • a Boiling Water Bath (BWB) canner is the right tool for acidic fruits, or for acidified foods such as pickles. Check the charts if you’re not sure of the acid content of your target food. If you’re canning tomatoes specifically, use litmus paper to determine the overall acidity of each batch. Some require additional acid in order to be canned safely for the long-term.
  • a BWB canner can be a dedicated tool, made specifically for the task … or it can be nothing more than a deep soup pot with a metal rack in the bottom of it. Both work the same way.
  • follow other people’s proven recipes precisely. If it says “BEFORE you put it into jars … bring your food to a rolling boil that you can’t stir down easily” … then be sure to boil your food according to that specification. It may/may not change the overall consistency or flavor, but that one step kills bacteria … which is important when it comes to long-term canned goods.
  • be sure to sterilize your jars, rings, and tools well before you begin.
  • DON’T overboil your flat, rubber-gasketed lids. A 2-minute bath in boiling water is sufficient, as long as you’re careful to not re-infest the lid with canning cooties before you even get it on the jar. Likewise, be careful handling sterilized jars and rings. It only takes setting a jar in the wrong place to contaminate it.
  • ALWAYS cover your filled jars with at least two inches of boiling water. Three inches is even better.
  • NEVER start your timer on your filled jars until your water comes to a hard, rolling boil.
  • ALWAYS let your BWB canning pot stop its active boiling before you start to take jars out of the water. Set them aside in a non-drafty place until they cool and seal.

If you have questions or if I haven’t been clear here, you can always write me at lane@afoodjourneytogo.com … and I’ll try to answer your questions :)

About Lane

Just a canner ... on this food journey called life :)
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11 Responses to Let’s talk canning basics: Boiling Water Bath Canners! :)

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  10. Felina says:

    Thanks for all the info! :) As a little girl, I used to watch my mom “magic” delicious food into jars using a giant pot every summer, but never got to learn the tricks before she passed on. I’m 23 now and eager to restart that tradition now that my dad’s berry bushes are in season; this page has really helped me prepare.

  11. Lane says:

    Hi Felina! :)

    I LOVE berries of all kinds. They’re my absolute favorites … so I’m envious of your Dad’s bushes … and your access!

    Happy canning! :)

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