Do Jars Have To Be Fully Submerged When Canning?

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Canning can be very confusing and small decisions like keeping the canning bottles submerged or not can have a huge impact on the entire process. 

Some say that it is okay to not fully cover the bottles while others believe that you must always cover the entire bottle while boiling it in water.

So, do jars have to be fully submerged when canning? Yes, to create a successful seal, you must submerge the bottles in water so that residual air can get out but not get back in while the bottles are canning. Once the bottles are free from air, a vacuum will form to seal in the contents. 

Canning is a complex process but if you follow the steps correctly, you can easily can food in every attempt! 

Read below to learn more about canning, how to do it properly, and a few best practices that you must follow to successfully can food!

How To Properly Can Food

Canning makes for an excellent home project and you would be surprised by just how easy this process is. 

Most people try to stay away from canning because they perceive it to be too difficult but in reality, it is quite easy to create a vacuum seal at home without using fancy equipment. 

We’re here to tell you that you can easily store food for the long term with just a canning jar, brine, a large pot, and very hot water.

The process of canning and preserving food involves two key components: brine and hermetically sealed bottles.

The salt brine is what will preserve the color, flavor, and texture of food while the hermetically sealed jar will ensure that the food remains free from rot and bacteria.

“Hermetically sealed” here just means that you will need to create a vacuum seal to keep air out

If you have tried canning in the past and failed, then you might not have followed the instructions properly or, the most common problem is that the jars weren’t fully submerged during the “water-bathing” step.

The water-bathing method is the preferred way to can food at home. It requires minimum utensils and you can get done with the project within 45 minutes

As stated, the reason why the bottles need to be fully submerged is to prevent air from getting in through the gaps of the cap as the bottle is sealed during the water-bathing process. 

Remember, the jars will only have a perfect vacuum if there is no air inside of the container throughout the process!

Even if just a few bubbles end up inside, the jar will not be safe to store for the long term. Don’t worry though, with the following steps you will have perfectly sealed bottles, virtually every time!


  • Canning jars with lids.
  • A large pot (to hold all the canning bottles)
  • A plastic spatula
  • Tongs


  1. First, sanitize the jars and lids so that they are free from bacteria. Start by washing all the equipment with an anti-bacterial detergent. Rinse with water until all the soap has been removed. 
  2. Fill a large pot halfway with water and then bring it to a rolling boil. Then, add the lids and jars separately to the water. It is important to keep the jars submerged for this step as well to kill off all bacteria in and around the jar. 
  3. Once done, remove all the jars and lids and keep them on a clean cloth over the counter.
  4. Meanwhile, prepare the brine and food as per the recipe and fill the jars with whatever you want to preserve. Make sure to leave a bit of headspace between the jar and the lid so that the jar closes easily without the food pushing against the lid from the inside. 
  5. Use a clean damp cloth to wipe away any residue from the corners of the lid.
  6. Use the plastic spatula to remove any air bubbles from the bottle. You can do this by carefully inserting the spatula inside the jar and then slowly twisting it until all the air bubbles have been eliminated.
  7. Use the tongs to carefully pick up and then place the jars inside the large pot. Add more water to the pot as needed to fully submerge the jars. 
  8. Put the heat on high and allow the jars to can for about 20 minutes or as recommended in the recipe. Make sure that you add adequate water so that the canning jars aren’t exposed to the air during the boiling process.
  9. Once done, allow the jars to sit in the water for about 5 minutes. Then very carefully pick them up and place them over a clean cloth on the counter. Do not check or twist the lids in any way!
  10. When the jars have cooled down, inspect them to ensure that they have a vacuum. You can do this by pressing the middle of the cap. If the cap presses down and pushes back up again then this would indicate that the jar has NOT been vacuum sealed. If there is no pushback and you just feel a solid surface with no indent then that would indicate that the canning process was successful and that you have created a vacuum within the jar. Repeat this step with every jar and separate all the non-vacuum ones. 
  11. Store the vacuum-sealed jars in a cool and dark place. Meanwhile, you can store the unsuccessful jars in the fridge. Consume the contents in the non-vacuum jars within 3-4 days

Remember, canning isn’t an exact science. This is why you are bound to be left with 1-2 unsuccessful jars. However, this method will greatly increase your chances of success too!

Best Practices For Canning 

When canning food, you must understand that brine plays as big of a role as the vacuum seal. This is why we recommend that you always follow a well-reviewed recipe to bring down the chances of failure. 

Also, make sure that you bring the water to a rolling boil when you sterilize the jars and lids and also when you add them to the water bath. The temperature of the water should be 212°F during the canning and sanitization process. 

There is no set time for how long you should leave the jars during the water-bathing step because it depends on the quantity, size, and contents of the jar.

You can follow the specifics in the recipe. If the instructions are not clear then you can generally let the jars boil for about 20-25 minutes

Also, always go for high-quality canning jars. The cheaper ones can easily crack under pressure or with high heat. These ones are a great choice! They’re durable and super quality.

Even a hairline crack may result in disaster, especially when it comes to the longevity of the food. We recommend shopping for good-quality canning jars online for the best results. 

Tips and Tricks

  • A jar rack is a great investment, especially if you are looking to pursue several canning projects at home. The rack will prevent the jars from making direct contact with the bottom of the pot, thereby reducing the amount of direct heat applied to the jar. This one is definitely our favorite and a great pick for beginners! 
  • Always get canning jars that can easily fit the largest pot in your kitchen. Many people make the mistake of purchasing the canning jars independently, only to find that they don’t fit and can’t be submerged within the pot. 
  • Start small by canning smaller quantities in smaller jars. Once you perfect the method, you can use the same techniques on bigger projects with less chance of failure. 
  • During the water bathing process, make sure that the water level in the pot is sufficient enough to keep the jars submerged even after some of the water has evaporated. Adding more water to a rolling boil will lower the water temperature and may interfere with the canning process.

Related Questions 

Canning is an extremely convenient and fun way of storing excess food for the long term. Trust us, once you get into the habit of canning food, you might never want to go back! 

Now that you know how to properly can food, here are some related questions to help you in your canning journey:

Can you use plastic jars for canning?

Yes. While most canning jars are made from a combination of steel lids and glass containers, you can also find high-quality and food-safe plastic jars.

These jars can be more convenient and secure as they are virtually safe from breakage. 

However, traditionally, glass containers fare better overall, especially when canning dense, solid foods.

Can you re-can unsuccessful jars?

No, once the jar has failed to seal, it is much better to just consume its contents over 2-3 days instead of canning it again because you will have to repeat the entire process from the start

Not to mention, the jar will further be subjected to boiling temperatures—which may ruin the flavor and appearance of the food! 

If you’re looking for a fun introduction to canning, this video from the folks over at Babish Culinary Universe is a great way to learn how!

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