Glass jars allow you to store food hygienically and safely. You can use them to preserve perishable and non-perishable ingredients, both dry and wet, as long as you store them in a cool, dry place. Probably the most common way to seal glass jars is to boil them in water and then leave them to soak until they have cooled. Alternatively, you can use a vacuum sealer or the much-loved sealing wax method. Once sealed, the jars will keep their contents securely for years, preventing their natural decay.
Method 1 of 3: Boiling
Step 1. Prepare the glass jars
Before you begin the process of sealing the jars, do some foreplay. Inspect lids and containers for any cuts, cracks, or uneven or sharp edges. Check both the inside and the outside of both. Make sure the lids match the jars perfectly. If necessary, discard the defective items. After making sure that all jars are safe for use, wash them manually in hot soapy water along with their respective lids. After cleaning them carefully, place them to dry on a rack or a clean kitchen towel.
Step 2. Sterilize the jars
Place them in the bottom of a large pot filled with boiling water before it reaches a boil. The pot will need to be large enough to allow the water to submerge all the jars. Bring the water to a boil, then let the jars soak until ready to use.
On the market there are special sterilizing pots, specifically formulated to arrange the jars in convenient baskets that are submerged by boiling water. If you make preserves frequently, consider purchasing one. The greatest advantage offered by these pots is their convenience, but if you don't have one you can achieve the same result using a normal large pot
Step 3. Prepare the contents of the jars
If you want to seal the jars with the boiling method, you need to make sure that the contents are naturally acidic or contain an added acid. This is in fact the only way to ensure that bacteria do not develop inside. While the jars are sterilizing, prepare the recipe you intend to keep.
Foods with a high acidity content include: fruit, fruit juices, jams, jellies and other fruit creams, gravies, sauces, tomatoes (with an added acid element), pickles, chutneys, vinegars and condiments
Step 4. Prepare the water for soaking
First, turn off the heat under the pot you sterilized the jars in, then remove them one by one with a pair of kitchen tongs. Alternatively, you can purchase one of those specially formulated baskets to submerge, hold and lift jars without risking burns with boiling water. Of course, using a basket is safer than using tongs. Arrange the jars to dry on a rack or clean kitchen towel. Once the pot is empty, turn the heat back on to bring the water to a light boil.
Step 5. Fill the jars
Set the boiling water aside, then pour the contents into the jars. If possible, use a funnel with a wide mouth; in this way it will be very easy to transfer the liquid or semi-liquid substances.
- Remember to leave some room for air. If you want to store soft, spreadable ingredients, such as jellies or jams, leave about half an inch of space. For solid ingredients, such as fruit or pickles, leave an inch of space. Now close the jars with lids, then screw the outer rings, typical of canning jars.
- Tap the jars on one side using a wooden spoon to remove air bubbles.
- Repeat the same process with all the jars.
- Do not screw the ring too tightly, otherwise the excess air will not be able to escape.
Step 6. Place the jars in the basket
In addition to protecting you from boiling water, the basket ensures that the jars do not hit the bottom of the pot and risk breaking; at this stage of the process it is therefore important to have one. Never stack jars on top of each other; if you need to seal many, repeat the process several times, depending on the size of the basket.
Step 7. Immerse the basket in boiling water
Submerge the jars completely by inserting it into the pot carefully. The boiling time varies according to the content, follow the directions in your recipe.
- The boiling time begins when the water starts boiling again.
- Check that the jars are submerged in at least 2.5-5cm of water. If necessary, add more before bringing it back to a boil.
Step 8. Remove the jars from the pot
Take out the basket with the jars, then place it on the kitchen worktop; you will have to let them cool without touching them all night. Wear a pair of oven mitts when handling the basket to avoid burning yourself with boiling water. If you need to remove the jars from the basket while they are still hot because you need to seal others, use a pair of tongs.
Step 9. Once cool, store the jars in a cool, dry place
Check the lid, if a slight depression has not been created, it means that the process has not happened correctly. If so, consume the contents immediately or repeat the process using a new lid. Make sure the glass is perfectly intact before starting over.
Method 2 of 3: Vacuum packed
Step 1. Purchase the necessary tools
What you need is a vacuum packing machine equipped with an accessory for glass jars and bottles. This complement must be connected directly to the mouth and allows you to suck the air from the jar to seal the contents.
Step 2. Sterilize the jars before sealing them
As a precaution, it is always best to sterilize any container. You can boil them in boiling water or wash them in the dishwasher at a very high temperature. If you intend to use a saucepan, make sure it is very large so that the jars are completely submerged. Bring the water to a boil, then reduce the heat and let them simmer until ready to use.
Step 3. Fill the jars
While you wait for the sterilization process to be complete, prepare the recipe you intend to keep, for example turning fruit into a jam or jelly. Many people also choose this method to preserve fragile and delicate objects that cannot be sealed in common vacuum bags. For example, you could fill the jars with small candies or nuts.
- When the recipe is ready, you can take the jars out of the water. If you haven't arranged them in a basket, use a pair of tongs, preferably specifically formulated to grab the jars. Let them dry before filling them.
- As explained above, it is important to leave some space between the ingredients and the lid. If you want to store soft, spreadable ingredients, such as jellies or jams, leave about half an inch of space. For whole ingredients, such as fruit or treats, leave an inch of space.
- Use a non-metal spoon to remove air bubbles. You have to slide it along the inner surface of the jar, gently pressing the ingredients down. You can use a wooden, plastic, or silicone spoon.
Step 4. Prepare the machine for the vacuum sealer
Once the jars are full, you can give the process away to seal them. Place the lid on the jar, for now without adding the ring, then connect the two ends of the flexible tube: one to the vacuum machine, the other to the adapter to be placed on the jar. Now attach the adapter to the jar, making sure it fits snugly so it doesn't fall out once the machine is operated.
Step 5. Turn on the vacuum machine
At this point you should follow the directions in the instruction manual. In general, in most cases, you will simply have to turn on the device and wait for it to indicate that the jar has been sealed. Once ready, you should hear the lid "snap"; Additionally, you may see or hear a signal indicating that the process is complete, such as a green light.
Step 6. Screw the ring onto the lid
Disconnect the tube from the adapter, then detach it from the jar. Now screw the ring tightly. Store the jar in a cool, dry place.
Method 3 of 3: Sealing wax
Step 1. Get all the necessary materials
To seal the jars with wax, you need a ceramic stove to melt the sealing wax (also known as a "wax melter"), fiberglass-reinforced adhesive tape, a pair of scissors, a candle, lighter or matches, and some sealing wax granules. Most of these items are readily available in DIY stores; alternatively, you can place an order online. This method is particularly suitable for sealing slender-necked jars and bottles.
Step 2. Set up the stove on the table
If your wax melter has a space in which to insert the candle, all you have to do is place it directly on the table; otherwise, you will have to place it on a small grid to be able to place the candle under it.
Step 3. Light the candle
The ideal is to use one of those round tea lights (also called "tealights") that are readily available in all supermarkets and home furnishing stores. Once lit, place it under the ceramic stove.
Step 4. Heat the sealing wax
Pour the granules into the stove, you can use any color you like. As they begin to melt, add more until the liquefied wax is only 2cm from the edge of the stove.
It will take about 20 minutes to melt the wax. Blow out the candle as soon as you are done
Step 5. Pour the ingredients into the jar or bottle
Now screw the lid tightly. If you don't intend to eat the contents of the jar, you can use a cork.
Step 6. Seal the lid with reinforced adhesive tape
Wrap it several times around the cap or lid, where it is in contact with the glass. When you're done, cut the tape, fold the end back on itself, then press it against the rest of the tape. The folded part will allow you to unwind and remove the tape when opening.
Step 7. Dip the lid into the wax
Turn the jar upside down, then dip the lid into the melted wax. Wait a few moments before lifting it again. Turn it over immediately to prevent the wax from dripping.
Step 8. Personalize your creation with a seal
This step is optional. If you have a seal, you can press it against the still soft sealing wax right after you turn the jar upside down. Embossing your initials or a particular symbol is a perfect way to personalize your work. Before moving the jar elsewhere, wait until the wax is completely dry.