The boiling point of water decreases as altitude increases, which means that when canning at higher elevations you must process food longer in a boiling water canner. At sea level, the temperature of boilingw ater is 212 degrees Fahrenheit. The boiling point of water drops 2 degrees for every 1,000-foot increase in elevation. The altitude of America's Test Kitchen in Brookline, Massachusetts, and where we developed all of our recipes, is 50 feet, or basically sea level. To determine your elevation, you can Google the altitude of where you live, go to the website veloroutes.org/elevation, or download a free smartphone app such as My Altitude.
foolproof preserving
How Altitude Affects Canning
When it comes to canning, your altitude affects boiling time and, ultimately, safety. Here's a chart to follow when making jams, jellies, preserves, or chutneys at any altitude.
By Published May 8, 2017.
| Height (ft) Above Sea Level | Minutes Added to Processing Time |
|---|---|
0-1,000 | 0 |
1,001-3,000 feet | 5 |
3,001-6,000 feet | 10 |
6,001-8,000 feet | 15 |
8,000-10,000 | 20 |
10,000+ | 25 |
Eat Those Summer Tomatoes Year-Round
Foolproof Preserving
The art of preserving produce has come full circle, from grandmother’s kitchen to a whole new generation now eager to learn how. This detailed, step-by-step guide from the experts at America’s Test Kitchen is perfect for first-time and experienced canners alike. You’ll get 110 foolproof recipes across a wide range of categories, from sweet jams and jellies to savory jams and chutneys, pickles, vegetables, fruit in syrup, condiments, and more.Buy the Book
What's your favorite ingredient or recipe to can at home? Let us know in the comments! And for more on canning, check out these posts: