Canning without a canner

This page exists because "you need a canner" stops a lot of people from starting, and it is often not true. A water bath canner is a deep pot with a rack. If you own a deep pot, you are most of the way there — and the jars you would have to put off buying are the part that actually matters.

The two requirements, and how to check them

1. Depth

The NCHFP requirement is that the canner "must be deep enough so that at least 1 inch of briskly boiling water will be over the tops of jars during processing." You also need room above that so a rolling boil does not empty itself over the side.

So: jar height, plus 1 inch of water, plus 2 inches or so of freeboard. A quart jar is about 6 1/2 to 6 3/4 inches tall, which puts you around 10 inches of interior depth. A pint jar is about 5 inches, so pints need roughly 8 inches. That is why plenty of pots can handle pints and cannot handle quarts, and it is the most common reason an improvised setup fails.

2. A rack

Jars must not sit directly on the base of the pot. A jar in direct contact with a hot base can crack from thermal shock, and water needs to circulate underneath so the bottom of the jar heats at the same rate as the rest.

• A round cake cooling rack that fits the pot is the best improvisation and is what most people already have.
• A steamer basket insert, if it sits flat and holds the jars level.
• A silicone trivet or a folded silicone mat, provided it does not float and does not block circulation.
• Extra screw bands tied together in a single layer — an old trick, and it works, though it is fiddly to lift out.
• A canner rack bought separately. They are inexpensive and they are the right shape, which is worth something.

What an improvised setup cannot do

It cannot change what a water bath is for. High-acid foods only — jam, pickles, fruit, acidified tomatoes. A stockpot is exactly as unable to pressure can as a purpose-built water bath canner, and no improvisation gets around that. See what can you water bath can.

It also will not fix a pot that is too shallow. If your only pot handles pints but not quarts, can pints. That is a completely legitimate way to spend a season, and pints are the more useful jar for most households anyway.

When to buy a proper canner

Three signals. You want to can quarts and your pot is too short. You are canning often enough that not having a dedicated pot is annoying — a canner is deeper, comes with a fitted rack and lets you keep your good stockpot for cooking. Or you are moving to low-acid food, at which point you need a pressure canner rather than a bigger pot.

When that time comes, best water bath canners has the picks, and measure your element first — the NCHFP's 4-inch rule catches more people than the price does.