Hopefully, your strawberry plants produced abundantly this year and will for many years to come. One of the favorite strawberry-related summer traditions is the production of strawberry freezer jam. Making freezer jam is an art in its own right, but this tip can help you be a successful (and healthy) canner of jams.
Strawberry freezer jam is considered to be a member of the strawberry preserves family, and the instructions for preserving are quite important to follow carefully to ensure that the canned freezer jam won't pose a health risk to those who consume it later. However, when instructions are given, it is important to factor in the altitude at which the cans will be be boiled (in a water bath canner).
As altitude increases, pressure decreases. When atmospheric pressure decreases, the boiling point of water decreases. This means that water will boil at a lower temperature. Since high, bacteria-killing temperatures are required to ensure that the substances being canned are safe to store, water must be boiled for longer periods at high altitudes to ensure the same effect that boiling at lower altitudes achieves in less time. So, here is what you need to know:
Boiling Times for Strawberry Freezer Jam
Follow whichever recipe you choose for your strawberry freezer jam. Prior to placing the jars in the water bath canner, look up your altitude (you can also check with your county extension agent for this information). Once you know your altitude, use this simple chart to add time to the recommended boiling time as your elevation dictates:
Of course, strawberry freezer jam is so delicious, you'll probably not see it still on the shelf after a year anyway! But, just in case you do, ensuring that adequate temperatures were attained while boiling will allow you to store your jars of strawberry freezer jam on a cool and dark shelf for up to five years.