Altitude Adjustment

Altitude Adjustment

My canning friends, sometimes we have to look at our situations and say to ourselves, “I need an altitude adjustment.”

It’s all science, like so much of canning is. 

At sea level, and up to 1000 feet above sea level, water boils at 212 degrees Fahrenheit.

However, once you get above the 1000 foot mark, the changes in atmospheric pressure means that your boiling point is actually LOWER than 212F. 

Altitude	Temperature at which Water Boils
10,000	194°F
8,000	197°F
6,000	201°F
4,000	204°F
2,000	208°F
0 (Sea Level)	212°F

For water bath canning, food safety requirements mean that the goodies inside your jars should reach 212F, and if it doesn’t you have to add to your processing time in order to make your preserved food safe.

For water bath canning, add 2 minutes of processing time for each 1000 feet about 1000 feet that you are.  To use the following chart, take the basic processing time and add to it based on your local elevation.

Altitude Adjustments for Water Bath Canning
Elevation	+ time
1000-2999	5 minutes
3000-5999	10 minutes
6000-7999	15 minutes
8000-10,000	20 minutes

Pressure canning requires that your food reach 240 degrees Fahrenheit.  Additional pressure is needed in this case, as opposed to additional time.  The standard rule is to add 1 pound of pressure for each 1000 feet above sea level you are.  However, you will rarely ever adjust more than 5 pounds, regardless of your elevation.  

For safety reasons, pressure canners should never be used above 17 pounds of pressure.

Adjustments for Pressure Canning
Altitude		Additional Pressure
1001-2000		+ 1
2001-4000		+ 3
4001-6000		+5
6001-8000		+5
8000-10,000		+5