Unlocking homemade preserves: Techniques for effortless access
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 are much cheaper and often healthier than similar store-bought products. The issue arises when opening them. Firmly vacuum-sealed lids effectively prevent spoilage of the contents, but they can be a nuisance when you need to open a jar quickly.
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 layer of air inside no longer presses against the jar's walls with the same force. A vacuum forms, which is visibly noticeable as a sucked-in, concave lid.
Common methods for opening jars
When you're unable to open a jar with your hands, likely the first thing you reach for is 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—table knives, spoon handles, and teaspoon handles—are used. Unfortunately, this method often damages the utensils, lid, and jar. A warped lid can no longer be reused. Air can penetrate subsequent preserves through the resulting gaps, spoiling 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 cause another change in pressure inside the jar, making it easier to unscrew. However, caution must also be exercised with this method.
Too large a temperature difference can cause the glass to crack. Therefore, do not immerse a jar in hot water immediately after taking it out of 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 down in a pot of hot water. Remember to use an oven mitt or wrap the jar in a cloth to prevent burns.
