Never Lay Jars on The Side When Canning

Turning you jars on the side for canning is not a good idea.

Links Mentioned in the Video:

• Resources for Canning Tomatoes

I got a great question recently from someone who was canning tomato sauce for the first time.
So Jake asks, “I am going to take my first crack at canning tomato sauce this weekend and I have a question about the water bath. The pots I have are not tall enough for the cans to have two inches of water above them, not even one. My question is, would it be okay to lay them on their side? I don’t see an issue, but I am in no way an expert.”

First as a side note, for my audience here today, tomatoes can be processed in either a water bath canner or a pressure canner; either one works.

Back to the question:

“Would it be okay to lay the jars on their side while canning?”

That’s a really common question — especially when you’re working with tall jars and smaller stockpots. But the short answer is no — turning jars on their side while canning is not safe.

Let’s talk about why that is, what can go wrong, and what you can do instead.

Why You Should Never Turn Canning Jars on Their Side

At first glance, it might seem harmless. After all, the jar lids are screwed on tight, right? So what’s the problem with laying them down?

Here’s what actually happens inside those jars during canning:

• As the contents heat up, they expand and vent air through the lid.
• That venting process is how a proper seal forms when the jar cools.
• If your jars are on their sides, the hot liquid (like tomato sauce) can start to leak out around the lid.

When that happens, you can end up with:

• Food particles trapped under the seal, causing it to fail later.
• A messy canner full of tomato sauce. Ugh.
• Jars that don’t seal properly — which means unsafe food.

So even though it might seem like a clever space-saving trick, turning jars on their side while canning can lead to spoiled food and failed seals.

The Right Way to Water Bath Can Tomatoes

If your pot isn’t tall enough to cover your jars with water, don’t worry — you don’t have to buy an expensive water bath canner to do it right.

You can use any large pot, as long as you follow these rules:

1. Keep the jars upright. They must always be standing straight up.
2. Use a rack (or even a folded kitchen towel) in the bottom of your pot to keep jars off direct heat.
3. Cover the jars completely with at least 1 inch of water — 2 inches is even better.
4. Maintain a gentle boil during processing.

If your pot isn’t tall enough to fully submerge the jars, it’s better to switch to smaller jars or find a deeper pot rather than trying to tip them sideways.

A Note on Tomato Processing

Tomatoes are one of those foods that can be processed safely in either a water bath canner or a pressure canner.

Both methods work well, as long as you follow safe, tested recipes and use the correct processing times. If you want step-by-step instructions, I’ve got full guides to both methods linked on Simply Canning.

Just remember — no matter which method you use, jars should always stay upright the entire time.

Conclusion

So, to wrap it up — don’t turn jars on their side while canning.

It might seem like a harmless shortcut, but it interferes with proper venting and sealing, and it can leave you with a mess (and possibly unsafe food). Keep your jars upright, make sure they’re fully covered with water, and you’ll have beautiful, safely canned tomatoes ready for the pantry.

Thanks for the great question — and happy canning!