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How Much Water to Put in a Pressure Canner | Quick Guide

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About 3 inches of water should be put in a pressure canner. Plenty of water is required to generate enough steam, so our canning attempt doesn’t fail. Also, not using enough water can ruin both the canned food and the canner itself.

Some sources go as low as 2 inches while others go up to 4. The number 3 is not only the middle ground, but it also tends to work with different shapes and sizes of pressure canners. But you don’t want to measure only with your trusted school ruler – we have to account for the rack as well.

Look for Water Level Marks or Notches Inside

Some manufacturers mark water limits on the inside of the pot. So, pretty much, all you have to do is do as you’re told and fill the canner up to that mark.

But if you find multiple marks higher up, that can get a bit confusing. Most likely, the canner also works as a pressure cooker, and those are the marks for maximum fill levels for grains, stews, soups, etc.

In short, if it goes above 3 to 4 inches, it has nothing to do with canning.

Why Is the Amount of Water Important?

Pressure canners are siblings of pressure cookers. They trap steam which in turn builds up pressure. As the pressure increases, so does the boiling point of water as well. This means that they run hotter and finish the job faster than the more traditional canning methods. This is also why pressure canners are better for preserving low-acid foods and what makes them super-effective at killing all the microbes.

While pressure canning uses less water than a boiling water bath, it still requires more than the standard pressure cooker. More water means more pressure and processing power. It’s one of the reasons why you have to make sure you’re adding enough of it into the pot and why pressure canners tend to be at least twice the size of a standard pressure cooker.

To illustrate the point: pressure cookers need only 1 cup of water, while a small pressure canner can easily require more than a quart. In terms of processing power, that translates to a pressure cooker being the equivalent of you gently simmering jam on the stove, while a pressure canner is very much like boiling jars with said jam to preserve them.

Anne-James-Pressure-Cooker
My trusty pressure cooker.

Can I Put Too Much Water in My Pressure Canner?

You can definitely put too much water in the pressure canner. In fact, it can have a significant detrimental impact on the canning quality. Too much water and it may end up in the jars, ruining all your preserving efforts.

Going a few ounces over the recommended amount is not a big deal. Still, avoid submerging the jars in water by more than halfway.

How Much Water Do You Put In a 7, 16, 0r 22-Quart Pressure Canner?

Antique-Pressure-Canner-With-a-White-Background

You can always put a rubber band on a plain school ruler and use it as a guide. But if you don’t have any handy, here’s a quick list of the most common sizes and amounts of water they will need. Keep in mind that these are rough estimates and that the shape and dimensions of the canner will have a great impact on the exact numbers.

  • 7-quart canner = 1.5 quarts of water.
  • 10-quart canner = 2 quarts of water.
  • 16-quart canner = 3 quarts of water.
  • 22-quart canner = 4 quarts of water.
  • 30-quart canner = 5.5 quarts of water.
  • 41-quart canner = 7.5 quarts of water.

How High up the Jars Should the Water Be for Pressure Canning?

Unlike boiler canners where jars have to be submerged in water, in a pressure canner, they don’t even have to be in contact with it at all. Since steam is doing all of the heavy lifting, the only thing that matters is that there is a bit of space in between jars for it to circulate.

Though that’s what’s most likely to happen in a commercial canner, at home, your jars are most likely to be submerged in water at least somewhat. Anything between an inch or two to halfway the size of the jar is perfectly fine.

Placing the Rack in a Pressure Canner

When setting up the rack, most people use old canning rings to lift it off the bottom of the canner. This creates more space for the water and raises the jars off the hottest part of the canner. You can either use the standard disc-shaped rack that probably came with your pressure canner or splurge on one with handles or that stacks.

Whichever rack you’re using, place it into the canner first before measuring the water. This is the best way to ensure that you’re using the correct amount.

By the way, all this water can lead to water stains on the jars and the canner. The easy way to prevent that is to add a splash of white vinegar into the water. Don’t worry; the vinegar will have zero impact on the canning process.

Can I Process Just One Jar in a Pressure Canner? How Much Water To Put In Then?

You cannot process only 1 jar in a pressure canner. All pressure canners have a mandatory minimum, and check the manufacturer’s instructions to learn more about your model’s limitations.

Whatever the minimum is, you still need to fill the canner with enough water, so it reaches about 3 inches in depth.

Can I Process More Than One Tier of Jars?

As long as the canner is tall enough and you have a rack, you can process as many tiers as you want. You’ll need to leave at least an inch or two of space between the top tier and the lid, as well as some space between the tiers so the steam can circulate.

The 3-inch rule still holds here, so don’t add more water just because you’ve (possibly) doubled the number of jars.

Does a Pressure Canner Need That Much Liquid When Used as a Pressure Cooker?

No, for pressure cooking, you need a minimum of 1 cup of liquid, no matter the size and capacity of the cooker itself.

However, though the technology is almost the same, not all pressure canners can function as pressure cookers. Therefore, ensure that the canner is marked as safe for this purpose before you try using it.

Do I Need More or Less Water When Canning at a High Altitude?

Regardless of the altitude, the water needed in a pressure canner stays the same no matter where you live. It will take slightly longer for the pot to come to pressure, but other than that, altitude has no impact on how you should use your canner.

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For more, don’t miss Can I Use A Pressure Cooker (Canner) For Making Jam or Jelly?

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