Canning 101: On Adjusting for Altitude

Columbia River Gorge hills

One thing I rarely mention in my recipes is the necessity to adjust cooking and processing times if you live more than 1,000 feet above sea level. I don’t bring it up often because even in my 20th floor apartment, I don’t come close to being that high up (the bulk of Philadelphia is at sea level and the highest portion of the city doesn’t go more than 500 feet above sea level).

Thing is, not all of you live in my lovely city and so elevation is something you do need to keep in mind. The reason it has an impact in canning is that once you get more than 1,000 feet above sea level, the temperature at which water boils gets lower (there’s a calculator here that allows you to plug in your altitude and get your specific boiling point).

If you use a thermometer to monitor the progress of your preserves, you don’t have to do too much to adjust during cooking. Just know that when your jam comes to a boil, it could still be a few degrees shy of 212¬į and may still have quite a way to go before reaching its set point.

However, elevation has more of an impact on the processing of preserves because once water boils, it can’t get any hotter. This means that even if your canning pot is happily boiling away, it might not be as hot as you think. The way that the USDA and the National Center for Home Food Preservation has you compensate for this temperature differential is by increasing processing time. Here’s the guide for making these adjustments.

1,001 to 3,000 feet, add 5 minutes
3,001 to 6,000 feet, add 10 minutes
6,001 to 8,000 feet, add 15 minutes
8,001 to 10,000 feet, add 20 minutes

If you live above 1,000 feet, you also have to adjust the amount of pressure you apply during pressure canning. The rule of thumb is that you need an additional 1/2 pound of pressure for every 1,000 feet you are above sea level. If you have a weighted gauge canner, you’ll just use the 15 pounds of pressure setting for any recipe that calls for 10.

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40 responses to “Canning 101: On Adjusting for Altitude”

  1. I am at 6000 ft. in Arizona. I really don’t have a problem with gelling, unless I am a little too liberal with the recipe! ūüôā You learn to adjust recipes when you live this high. After a while it becomes second nature, and you don’t even think about it anymore. I even have relatives that are at 8000 ft that have no problem with canning.

  2. Not sure about gelling. I live at 9200 ft in CO; when I make candies, I have to reduce the temperature called for (300¬į for brittles becomes 282¬į for me at my home).
    I haven’t done any pressure canning, but I may next summer. For water bath canning, I have to boil my jars for 35 minutes!

      • I was so angry when my favorite Christmas toffee was no longer sold nearby. I groused for about a week when I finally had my brain engage. I boiled water and used a candy thermometer to see our boiling point (199F) Then when making the candy I subtracted 13 degrees to the regime’s temperatures. With candy I was also able to verify my calculations with the water drop forms. I’m hoping that adding the extra timing will allow me to make my key lime marmalade. Thanks for the information.

  3. Interesting article, I’ve been living in the French Alps (for the winter season) and have had to adapt my way of cooking – it’s been a learning curve to say the least, and I hadn’t even thought about boiling temps for canning!

  4. I too am in Colorado and canning at 8300′. I would love to find someone that is also canning and water bathing at the additional 20 mins and 15 # pressure. Pickles are mushy, jelly can be runny and will not set….I need some advise with “altitude” Canning at #15 has not been a problem. Do you have any connections? thanks again for all the canning recipes and information I love your site and have past it along to many canning friend! Marilyn

    • I live in the Springs, and while not quite as high as you are, I haven’t had any issues with set. I just have to boil it a little bit longer and adjust the 220 temp accordingly.

  5. Thanks for the lesson! The picture at the beginning of your post looks like it was taken here in Kamloops. I didn’t think there was another place on the face of the earth that looked like that!

  6. Thanks for posting this! I’m at 3,440 feet and although I knew I should make a slight adjustment to my processing time, I’ve never seen a handy chart that told me how much longer I should go.

  7. I’m so happy to finally see this post! I sent you an email asking about adjusting for altitude a while ago and thought it may have been a good post for your canning 101 blogs. I thought that you didn’t think it was relevant or bother to comment on it. Thanks!

  8. We have been canning at 6500+ feet in Colorado for over 20 years. We always add 15 mins to our processing time for hot water bath canning. We’ve made lots of pickles and more different kinds of jams than I can count. The altitude has never been an issue. But thanks for discussing it. Food safety is the #1 concern. No one has ever gotten sick from anything we can and we’ve never had a jar go bad. We want that to continue

  9. Help!
    I’m using all different sizes of WECK jars. All my processing times are for mason jars in my recipie books. How do I know how long to process? Weck has so many different sizes not comparable to mason jars. Ahhhhhhhh help!

  10. I live in New Hampshire at 940 feet, so a heck of a lot closer to 1,000 feet than sea level. Is there any reason not to go with an extra five minutes?

    By the way, I just started canning last year. The blog is great, as is the book. I just used your dill pickle recipe on a bunch of pickling cucumbers straight from my garden.

    Regards,
    Bob

  11. I live at about 5000 feet, and already make the time adjustment for canning. However the problem I run into is getting my jam to the proscribed temperature. Last night I prepared your kumquat marmalade, and though I boiled it for more than an hour, it had not yet reached the suggested 220ňö (because of our low boiling point). I didn’t want to boil off all of the water, so just stopped it and proceeded. Do you have any suggestion for me? Do you think I should pressure cook my jam to get the pectin to extract ok?

    • Are your jams and marmalades ending up runny? If you can’t get to the proscribed temperature, it might be time to call in some additional pectin.

  12. So what if I didnt know that I had to increase the poundage and only cooked green beans and corn (seperately) at 10 pounds instead of 12? Is my food bad? Or does it just have a shorter shelf life?

    • If you didn’t process your food at a high enough pressure, it may not be safe. It’s not about it having a shorter shelf life or not. It can be incredibly dangerous if you don’t follow proper procedures.

  13. […] Process jars in a canner full of boiling water for 15 min. Adjust if greater than 1,000 feet for high altitude processing. Turn off the heat and let the jars stand in the hot water for 5 min. Transfer using a jar lifter […]

  14. I just canned some chicken and I got the altitude wrong. I canned at 14 pounds pressure when it should have been 11. How will this effect my chicken?

  15. I recently made and canned applesauce (first-timer to canning). I forgot about adjusting for altitude. We are at 1400′ and I should have added 5 min. to the boiling time. The jars all sealed (half-pint jars) fine. I’m so sad to waste all the ingredients and work. Will I be able to tell if the jars have gone bad?

    • If they spoil, they will either mold or begin to ferment. Neither are dangerous forms of spoilage and you’ll easily see or smell it when you approach the jar. Hopefully you won’t experience any kind of spoilage at all!

      • Thanks for your quick reply! Is botulism a concern? I opened a jar yesterday and it seemed fine but I didn’t know if botulism caused obvious signs of spoilage. I’m going to make your roasted corn salsa from your book soon and I’ll be sure to adjust the times this time!

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