Unlock the secrets to opening stubborn home-canned jars
Home-canned preserves for the winter are a luxury. In tightly sealed jars, you can capture the taste of tomatoes ripening in July or plums in September. Homemade jams and vegetable sauces you make yourself are often much cheaper and healthier than similar store-bought products. The issue arises when you need to open them. Firmly vacuum-sealed lids effectively prevent spoilage, but they can be a nuisance when you're in a hurry to open a jar.
Why is it so difficult to unscrew a jar of homemade preserves? It's due to the canning process. When a well-sealed jar with hot contents cools down, the pressure under the lid decreases. The cooled air inside no longer presses against the jar's walls with the same force—a vacuum forms, visibly noticeable as a sucked-in, concave lid.
Common methods for opening jars
When you cannot open a jar with your hands, you might first reach for a moist cloth. The material increases friction between your hands and the lid, which may help with the task. However, with strongly sealed preserves, this is often not enough.
Next, utensils come into play—such as table knives and the handles of spoons or teaspoons. Unfortunately, this method often damages both the utensils, the lid, and even the jar. A warped lid can no longer be reused. Air can penetrate subsequent preserves through the resulting gaps, causing spoilage of carefully prepared pumpkin purees or tomato sauces. Moreover, chipped glass fragments could enter the food, posing a health risk.
How to effectively open a jar without effort and risk of damaging the lid?
A good, albeit less popular, method is to place the lid under a hot stream of water. The heated metal lid will change the pressure inside the jar, making it easier to unscrew. However, caution must be exercised with this method.
An excessive temperature difference can cause the glass to crack. Therefore, do not immerse a jar in hot water immediately after removing it from the refrigerator. Wait until it warms to room temperature, then briefly immerse it in boiling water.
If you don't have access to hot tap water, immerse the jar with the lid in a pot of hot water. Remember to use an oven mitt or wrap the jar in a cloth to prevent burns.
