Canning is a traditional method of preserving food that involves filling glass jars with food and processing them at high temperatures. However, canning at high altitudes can be challenging because the lower atmospheric pressure can affect the boiling point of water. In this article, we'll discuss some tips and tricks for canning in glass jars at high altitudes.
Understanding the Effects of High Altitude
High altitude can affect the boiling point of water, which is a critical factor in canning. The boiling point of water decreases by approximately 1°C for every 1000 feet increase in elevation. This means that at higher altitudes, water boils at a lower temperature, which can make it more challenging to achieve the required temperature for safe canning. To compensate for the lower boiling point, the processing time and pressure for canning in glass jars at high altitudes must be adjusted.
Adjusting Processing Times and Pressure
To ensure the safety of canned foods in glass jars at high altitudes, it is necessary to adjust the processing time and pressure according to altitude. The processing time and pressure recommended in canning recipes are based on sea level, so they need to be adjusted to compensate for the lower boiling point of water at higher altitudes. Altitude adjustment tables are available to help determine the appropriate adjustments.
For pressure canning in glass jars, the pressure needs to be increased by 1 psi for every 2000 feet increase in elevation. For example, if a recipe calls for a pressure of 10 psi at sea level and you live at an altitude of 5000 feet, the pressure needs to be increased to 12 psi. It is also essential to adjust the processing time according to the altitude. For example, if a recipe calls for 20 minutes of processing time at sea level, it may need to be increased to 25 minutes at an altitude of 5000 feet.
For boiling water bath canning in glass jars, the processing time needs to be increased by 5 minutes for every 1000 feet increase in elevation. For example, if a recipe calls for 20 minutes of processing time at sea level and you live at an altitude of 5000 feet, the processing time needs to be increased to 30 minutes.
Choosing the Right Glass Jars
Choosing the right glass jars is essential for successful canning in glass jars at high altitudes. It is important to use jars that are specifically designed for canning and are free of chips, cracks, or other defects. Mason jars are a popular choice for canning in glass jars, as they are readily available and come in a variety of sizes.
JBC Online is a reputable supplier of glass jars suitable for canning. They offer a wide range of high-quality glass jars that are specifically designed for canning and come in different sizes to fit different food quantities. They can also suggest suitable jars based on the type of food you want to can, ensuring that you choose the right jars for your needs.
It is also essential to choose jars that are suitable for the type of food being canned. Low-acid foods such as vegetables, meats, and fish require pressure canning in glass jars, while high-acid foods such as fruits and pickles can be canned using a boiling water bath in glass jars.
Following Safe Canning Practices
Safe canning practices are critical for preventing foodborne illnesses. Always use fresh, high-quality ingredients and follow canning recipes carefully. Make sure to use the correct processing time and pressure for your altitude, and do not make any changes to the recipe that can affect the acidity or processing time.
Before canning in glass jars, sterilise the jars and lids by boiling them in water for at least 10 minutes.
When filling the jars, leave appropriate headspace as recommended in the recipe, usually ¼ to ½ inch from the top. This headspace allows for food expansion during processing and creates a vacuum seal when the jar cools.
After filling the jars with food, wipe the rim with a clean, damp cloth to remove any food residue or debris. Place the lid and ring on the jar and tighten the ring finger-tight, meaning it should be tight enough to hold the lid in place but not so tight that air cannot escape during processing.
When the jars are cool, check the seals by pressing on the lid with your finger. A sealed jar will not flex or move. Store the jars in a cool, dry, and dark place, and label them with the contents and date of processing.
Canning in glass jars at high altitudes requires some adjustments to processing times and pressure, but it is still a safe and effective method of preserving food. Choosing the right glass jars, following safe canning practices, and adjusting for altitude can help ensure successful preservation of your favorite foods. And, if you need help choosing the right jars, JBC Online is an excellent resource for finding high-quality glass jars designed for canning. Happy canning!