If the glass jar was closed correctly, then it is not so easy to unscrew the tin lid from it. You will have to make a lot of physical effort and show dexterity, since your hands will slide on both metal and glass. Fortunately, there are tricky ways to open a screw top jar. It is enough just to remember the school physics course.
Why banks don't open
Tin screw caps for cans are called twist-off. They are popular for their reusable use. But on the bank, they are held not only by the thread. During the preparation, the product is doused with steam or boiling water, due to which the polymer coating inside the lid softens, and the jar closes tightly. When the lid cools down, its top is pulled inward, and the strength of such an attachment is also maintained due to the vacuum effect. A sealed environment is an obstacle to the entry of microbes from the outside and a guarantee that the contents will remain edible for a long time.
In everyday life, other circumstances also interfere with opening the screw cap. So, for example, if you do this with wet hands, the jar and lid will slip. If the container has sweet contents (jam, honey or preserves), then the lid may stick. And if the pressure in the can is below atmospheric, then the lid retracts more than necessary.
Key for caps
The screw cap wrench works like a lever. This device is inexpensive and versatile, that is, it is suitable for covers of different diameters.
The key is easy to use. Just find a suitable hole for the diameter of the lid, put the key on the jar, tighten the handles and turn.
When unscrewing the cover, be sure to do it in the correct direction. In a clockwise direction, the product is twisted and opened in the opposite direction.
Tool-free methods
If special key for caps you don't have, increase the grip. Degrease and dry the jar and lid, wipe your palms: the friction force will increase and will play into your hands. You can also wear a rubber or silicone household glove, or cover the lid with a tea towel, plastic wrap, or sandpaper. You will have to apply a twisting force, but this will be easier now.
The metal expands when heated. Therefore, if you hold the lid under running hot water or put the jar upside down in a bowl of boiling water for 10 minutes, then unscrewing the twist-off will be much easier. Make sure that no water gets on the glass, as the jar may burst.
If the vacuum pulls the lid against the can too much, you can try to depressurize the container. To do this, insert a knife or the tip of a spoon or fork between the neck and the lid, then twist slightly. The edge of the lid will move away from the glass, and with a gap of only 0.5 mm, the can will be depressurized with a light pop.
When opening a can with a screw cap, be careful not to break it.
Use a lubricant for sticky contents. If there is honey or jam in the jar, turn it upside down and drip a little oil between the neck and the lid. After 15–20 minutes, the fat will penetrate the crevice, lubricate the surfaces, and it will be much easier for you to open the vessel. The lubricated thread will no longer stick, but if oil gets into the product itself, it will not have the best effect on its quality. So be careful.
Another well-known way to open twist-offs is to knock on the bank. You can either turn the container over and slap the bottom with your palm, or grab the bottom and slap the lid. The method works well in cases where vacuum is the only obstacle. Try to proceed with caution, otherwise the bank will simply break.
Finally, you can put the container on one side and roll the edge of the lid along the edge of the tabletop, pressing from above with your hand. From such manipulations, the edges of the lid can relax a little, a quiet pop can be heard. After that, the bank will open easily.
Having tried these simple ways, you can easily remove any cover. Before opening the jar, make sure it is worth doing. If the twist-off lid is swollen or cracked on the surface, the contents are most likely no longer usable. The same applies to expired industrial blanks.
18Previously, lids for hermetic rolling were almost always used, which were sealed with a special seaming machine. They had to be opened with a special can opener. But today, more and more often, preservation in glass containers is presented on store shelves, the lids of which have an internal thread. At the time of canning, you only need to tighten it tightly, sterilizing the contents of the cans. In winter, you just need to unscrew the lid and enjoy delicious delicacies.
But sometimes the stubborn lid with which the can is closed does not lend itself to opening, and despite all efforts, the shutter does not move a millimeter. Why doesn't it open. This is because during the packaging of products in cans, for example, pickled vegetables or pickled cucumbers, a vacuum forms in it that holds the lid. This, in turn, will protect the product from pathogenic microbes entering them. If you put a hot salad in a hot jar and screw the lid tightly, then when the jar cools down, a vacuum forms in it. There are some very simple tricks that you can use to open your jar effortlessly.
Method 1: Use rubber gloves or a towel
In most cases, you cannot open a can with a screw cap because your hands are too slippery. Wearing rubber gloves or draping a towel over the screw cap will provide more adhesion. After that, you need to try to unscrew the lid. Of course, you have to make an effort. If this trick is not enough, then you will have to use one of the following.
Method 2: Open with a knife
Insert a dull knife under the cover and bend it slightly. Thus, air can enter the opened space. This can be understood by the emitting hissing sound. After that, the lid from the can can be unscrewed without any problems in the usual way.
Method 3. Hole in the lid
Like the last trick, this one works as well. Let air seep into the inside of the can. This can be achieved by punching a small hole in the lid with a sharp object such as a knife. But you have to be extremely careful not to cut yourself. This will lead to depressurization of the can. After that, you will either need to glue the resulting hole or transfer the contents of the can to another container so that it does not deteriorate.
Method 4. Hit with a glass bottom
This is often enough to make it easier to unscrew the lid by hand. You just need to lightly hit the bottom or lid of the can on a hard surface, such as a floor or countertop. You can hit the bottom with a straightened palm. This will create a water hammer that will target the tightly fitting lid. At such a moment, you can hear a specific click, indicating a depressurization.
Method 5. Hot water
It is necessary to hold the jar over hot water for some time, or open the hot water tap and hold the unpreserved under the stream. After that, it should be easy to open.
If there is a small sheet of sandpaper in the kitchen, then take it in your hand so that the rough surface is directed away from you. Then grasp the lid firmly with this palm and try to unscrew it. The jar must be handled in such a way that its lid is directed towards the floor. Then take some not very heavy object (for example, a knife) and gently, without applying force, knock on the lid from different sides. After such manipulations, the lids must definitely give in. There are many more methods to help you deal with tightly screwed caps. Some of them are very complex and others are quite simple. The main thing is to remember that all the manipulations will have to be done very carefully so as not to break the glass container and not get hurt.
Many compatriots mistakenly and naively believe that it is not possible to open a can of canned food without special tools (or at least a knife). It's not like that at all. In fact, the jar can be opened without much difficulty. Of course, if you know how to do it correctly and quickly.
So, notice that there is a rim on the lid of the can. Actually, it is the main obstacle on our way. What should be done in order to get rid of it? First of all, we find some kind of extensive hard surface, for example, asphalt. A concrete slab is also suitable, big Stone, a curb or a large enough piece of iron. Needless to say that on the street there are such objects around great amount both in the city and in nature.
We lean the tin can against the surface and begin to rub. The metal edges are actually quite thin. After a short time, it will be damaged, thereby ceasing to hold the lid. All that remains after this is to press on the jar with your fingers and remove the broken lid with your hands from the side where the friction was carried out.
Note: This method works with any cans. It is also good because there is no risk of injuring your hands.
Screw lids for canning differ from those that require the use of a seaming machine when closing them in that they can be used repeatedly. Their action is based on a very simple principle: polymers that are found with inside, under the influence of high temperature soften, thereby increasing the tightness of the closure. Then, as the lid cools, its upper part is pulled in, and a vacuum effect is created; and the lower polymeric layer begins to play the role of an airtight seal.
In order for the lid not to deteriorate and so that it can be used again with the same efficiency, it is necessary to be careful when unscrewing it. You can use a special tool for this. But if a person is strong enough, then he can open the can with his bare hands. However, most often the housewives deal with banks, who, of course, do not have enough strength to open tightly tightened lids without using a tool. When it is required to open a bank, a man can be at work or be engaged in other, more important matters.
Of course, sometimes even a physically weak woman can open a can. But most often, after applying maximum effort, the lid does not turn even a fraction of a millimeter. And this can be due to one or more of three reasons.
- The jar is much more difficult to open with wet and slippery hands. And if, at the same time, the jar itself is also wet, then it will become even more difficult to complete the task.
- Typically, the lid is flush with the jar. The tighter the fit, the more difficult it is to rotate. And if honey is stored inside, then the lid may stick to the neck at all.
- The pressure inside the can can be significantly lower than atmospheric pressure. Therefore, the cover is over-retracted, making it difficult to move when trying to unscrew it.
When you shouldn't open a bank
Before using any of the opening methods, you need to look at the jar and try to determine whether it makes sense at all to unscrew the lid and use what is inside for food. It is possible that the products could deteriorate during long-term storage. This is determined visually by the shape of the lid. If its surface is even, then most likely everything is in order.
If there is swelling on the surface, there is no doubt that the contents of the can have become unusable. In this case, it makes no sense to unscrew the lid. Otherwise, it will turn out that time and effort will be wasted. In addition, unscrewing a can of spoiled food can be fraught with consequences. The lid, barely moving from its place, can bounce up like a cork from a champagne bottle and hit right in the face.
Swelling on the surface of the lid is not the only visual indication that spoiled food is stored in the jar. This may also be evidenced by a crack on the bank itself. It can be large enough for air to enter through it along with dangerous microbes, subsequently infecting the entire contents.
It is even more dangerous to eat foods that could accidentally get into small pieces of glass. They can be so small that they cannot be seen with the naked eye, however, their danger does not decrease from this.
8 ways to open a can
If there are no visible defects on the lid and on the jar itself, then you can unscrew it. And if you do not have enough strength to do it with your hands without using any additional techniques, then you should use the helpful tips below.
1. Use of special tools
A special tin wrench can unscrew and twist cans without having any negative effect on either the lid or the glass. If such a tool is not yet available in the household, and problems with opening cans arise quite often, then you should think about purchasing it. Fortunately, its price is not high.
2. Light blow to the bottom
Apart from the above method, this one is the simplest. However, if you consider that to open a can with a key, you must first purchase the right tool, then hitting the bottom will be the simplest method.
And here's what you need to do: first, the jar should be turned upside down, and then, keeping it in weight, lightly hit the bottom. You can do the opposite: place the jar in the palm of your hand and knock on the lid.
Both versions of this method are quite effective. They always help when pressure differences are the cause of the problem. However, none of them will help with the adhesion of the cap to the neck.
3. Increased coupling
If your hands always slip when you try to unscrew the lid, then you can wear rubber or silicone gloves. Sometimes the problem can be solved with a regular towel. Polyethylene and sandpaper also contribute to an increase in adhesion.
You can try to twist not the lid, but the jar itself. True, even in this case, it is often necessary to make considerable efforts.
4. Application of physical laws
You can try unscrewing the lid with a genuine leather product. For example, a belt can be inserted into a buckle, then a lid can be inserted into the formed loop, tightened firmly and moved so that the can rotates in the desired direction.
5. Skating on a horizontal surface
Often this method turns out to be effective: the glass container is rotated 90 degrees, and the side of the lid is rolled along the edge of the table in one direction or the other many times; while you need to lightly press with your hand. A soft popping sound will indicate that the lid has become less snug.
6. Heating
You need to take a dish that is thicker than the diameter of the neck and pour hot water into it. Then the jar must be turned over and placed in this container with water. After waiting 10 minutes, you can turn the can over and open it. This is explained by the simplest physical law: when heated, the lid material expands.
The lid often sits so tightly on the can with the blanks that it is impossible to open it with your hands. The main reason is the difference in pressure, which was created during conservation due to the vacuum. It is he who does not allow the content to deteriorate. It also "pulls" the lid inward, preventing the lid from opening easily.
Difficulties due to vacuum arise when opening both plastic and iron lids. For the second, there is another reason - if the product is quite old, the metal of the lid could rust. Even a small area covered with rust "grabs" the lid. It sticks to the glass jar.
Separately, it should be said about cans with sweet products: with compotes, jam or condensed milk. If the can has been opened before, some of the product may have gotten onto the thread or rim. The sugar contained in it crystallizes, creates a layer, the lid sticks to the jar. It is not easy to reopen the lid.
The situation arises, described in the fable about the fox and the grapes. The eye sees the tasty contents, but you can't open the lid with your hand. But our people are not used to giving up. A few simple tweaks and the problem is solved.
Ways to open a can with a screw cap
Most canned food today has just such metal lids. This applies both to those sold in the store and to home supplies. Such a blank will easily open when the pressure inside and outside the can becomes the same. To do this, you need to let air into the jar. Typically, a counterclockwise spinning motion with little force, a light pop or hiss indicating air is entering, and the job is done.
If you cannot open it the first time, it is recommended to attract the brute male power of helpers from among friends and relatives. But how do you open a jar with a screw cap, even if it doesn't give up? We'll have to use improvised means, folk methods or special devices.
The use of improvised means and folk methods
The easiest and fastest way is to let air in by slightly bending the side of the lid. This can be done with an old knife or any other fairly hard object that can pick up the edge: a can opener, an awl, a metal ruler, cutlery.
Gently inserting a knife or other improvised object between the lid and the jar, you need to make a movement that bends the iron away from the glass. Hearing the sound characteristic of air penetrating inside, then unscrew the cover with your hands.
Important. As a rule, such mechanical interaction does not pass without leaving a trace neither for the lid, nor for the used item. Most likely, the lid will deform and become unusable for canning in the future, and improvised tools may bend. Knowing this, it is better to use an old knife or awl, which is not a pity.
Among the popular ways to solve the problem of how to unscrew the lid on the can, there are also such variations of mechanical impact: 
- hit the bottom sharply, holding the inverted can in the air;
- knock on the lid and sides of the can with various objects, for example, the handle of a knife or a kitchen spatula;
- roll the jar sideways on the table, then press the middle of the lid with your hand.
Unfortunately, they are ineffective.
Sometimes it seems that the lid is about to give in, so it's a pity to spoil it with a knife or an awl. But at the most crucial moment, the hands begin to hurt, or they begin to slip. To protect the skin of the hands, increase the adhesive force and at the same time not damage the cover, use:
- a damp dishcloth or rag that is used to cover and then rotate the lid;
- rubber gloves, both tight kitchen gloves and latex medical gloves;
- cling film for covering the lid, which is recommended to be pre-degreased;
- leather belt.
The belt is used as follows:
- thread the belt into the buckle, forming a loop;
- put a loop on the cover around the rim:
- tighten firmly in a counterclockwise direction;
- twist the can clockwise, at the same time pull the lid with a belt in the opposite direction.
In the case of the belt, the laws of physics concerning friction are used. The same science is applied by immersing a jar with a lid in hot water. In this case, the law of thermal expansion applies - since metal expands more when heated than glass, the lid becomes wider than the rim and opens more easily. To achieve the desired effect, it is enough to keep the jar in water for 10-15 minutes. After that, it is recommended to wipe it dry so that the laws of friction work better at the moment of unscrewing.
The method works well not only for new, but also for reopening cans with sweet contents. When soaking, hot water gets under the lid. Although it leaks out in microscopic doses, it is usually enough to dissolve the sugar crystals and eliminate the mechanical interference they create.
Important. You cannot use boiling water! The jar may burst from sudden heating. Of course, this is also a way to get content out of it, but too extreme and unprofitable.
Application of special devices
A special device for opening glass containers is a key, sold in most major hardware stores. It is a round rim with handles and works like a pliers:
- the rim is superimposed on the cover;
- a person squeezes the handles with his hand, minimizing the diameter of the rim as much as possible;
- thus, the lid is tightly gripped by these "round" tongs;
- without unclenching the handles, so as not to loosen the grip, the person makes a rotational movement counterclockwise;
- in addition to the tight grip, the leverage effect of the handles also contributes;
- a set of efforts leads to the opening of canned food.
Additional Information. The price of a special key is low. It is usually made of plastic. Has several internal diameters, so it can be applied to lids different sizes... Inside there are rubber pads that prevent the key from slipping around the cover.
V last years Internet commerce offers other options for special devices made of plastic, latex, and other materials. But for the most part, they use the same methods of influencing the cover as the described key, which remains the most famous and popular among consumers.
How to easily open jars with other lids
Although glass jars with metal screw lids are the most common, some canned goods have different lids and even a different look.
Glass jar with tin lid
Humanity has not yet figured out how convenient it is to open such jars, except for the opener. Other ways to deal with this kind of preservation are less comfortable. Craftsmen use an ordinary kitchen knife, pliers, and even open blanks with their fingers. It can be assumed that such methods were born in families where the wife likes to roll up a lot of products that are suitable for a snack, and it is not always appropriate for a husband to ask for a bottle opener.
The edge of a large kitchen knife sticks into the tin with enough force to pierce it through. If the contents are liquid, for example, compote, it can be immediately poured through the resulting hole. Otherwise, the manipulations with the knife are repeated until the hole is large enough to remove the product from the can. You can pick up the cover through the hole you made, and, with an effort, remove it.
Using the pliers, the lid clings to the edge, then pulls off the can.
Someone with fairly strong fingers can simply squash the lid in the middle. The changed geometry of the edges of the lid itself will lift it from the can.
Glass jar with plastic lid
Usually used when home canning... If it is difficult to remove it by simply hooking it with your fingertips, heat the lid in warm water using the same method as described for the screw cap. The plastic will soften and the lid will expand and become more pliable.
Heat the lid in warm water
As a last resort, the plastic lid can be cut off the can with a sharp knife.
Iron cans
There are several types of can openers for opening tin or iron cans:
- simple in the form of a short bayonet opens the cans with tearing movements, so it leaves a dangerous sharp edge, but it is extremely affordable;
- more complex, which uses a special cogwheel. With its help, the cutting surface smoothly moves along the edge of the canned food, the lid is removed neatly, without torn edges. These knives are more expensive but very comfortable;
- an electric knife that does not require hands to use. It is as safe as possible to use, but expensive enough to be purchased for an ordinary household. As a rule, it is present in gourmet kitchens or in places of public catering, where a lot of canned food is opened daily.
Alternative ways to open canned food in iron cans:
- with the help of a kitchen or penknife, with which one side of the can is methodically pierced along the side until it becomes possible to get the contents through the bent lid;
- using a file, knife sharpening bar or other abrasive products, from stone to asphalt. The rim of the can is rubbed with a rough surface until it is erased and the contents become accessible.
Whichever canning lids are used, the following conditions must be observed:
- the cover is not deformed, its surface has no mechanical or chemical damage;
- during storage, conditions must be observed in which the covers will not oxidize or damage. The room where they are stored has a normal temperature and humidity;
- any type of cap must be sterilized thoroughly.
Special techniques and folk ingenuity will help you open any jar with delicious blanks. Even if there are no special devices at hand.