How to determine the screw cap size for a jar. Which canning lids are best? How to close cans of tomatoes for the winter with iron lids
Along with metal lids, nylon lids are very popular among summer residents who make preparations for the winter. With their help you can close jars from 0.5 l to 3 l. The peak of their popularity came at the end of the 20th century.
When used correctly, a new nylon lid will close the jar as tightly as a metal sealing lid. At the same time, you can easily open and close the blanks in winter as needed (the metal lid opens only once).
Before use, the nylon lid is immersed in boiling water. for 10-20 seconds, where it is not only sterilized, but also additionally softened for a short period, which allows the jar to be hermetically sealed with a minimum of effort. No special equipment is required (for example, a seaming machine, etc.).
Many people write that you need to boil for 2-3 minutes. I believe this is wrong, you can simply ruin the lids, and subsequently their tightness will suffer.
Before use, it is advisable to dry sterilized nylon lids so that condensation does not accumulate under them after closing the cans.
You can buy nylon covers at your nearest hardware store or market. I recommend using them primarily to cover the jam. As a rule, we eat it slowly (gradually) and it is better that the jar does not remain open until the preparation is completely consumed.
The instructions on the nylon lid read: “For food products. Before use, wash with detergent. Before closing, keep the lid in boiling water for no more than 15 seconds.”
Appearance (standard) of a nylon cover from the times of the USSR (compare with what is sold in stores today).
The main advantages of nylon covers:
- easy to put on and take off;
- reusable;
- affordable price;
- do not rust and do not release harmful substances into workpieces.
You can also store cucumbers, tomatoes, bell peppers, zucchini, etc. under nylon covers for the winter. Everything will be kept intact for a long time.
Screw-on lids are a paradise for the housewife who has despaired of handling the seamer when canning with simple lids with an insertable rubber band.
Seaming machines often break down and then do not close at all or cannot press the lid and attach it to the glass of the jar very tightly. If the jar is not closed tightly, the products will deteriorate. And this is so offensive! So much work in a hot, stuffy kitchen, so many products, and suddenly it turns out that the jars are swollen (that is, the lids on them) or have completely fallen off.
Therefore, in order not to be unnecessarily upset, you need to either buy a reliable seaming machine for lids, or switch to twist-off screw caps.
Jars with a screw neck, closed with twist-off lids are the most common containers in which we buy mushrooms, jam, compotes, canned tomatoes, lecho, gherkins, ketchups in glass jars, mussels, some types of cheese, sun-dried tomatoes in oil, juices and baby food. Twist-off technology is used both for capping medicines and for beer caps.
Twist-off caps come in different sizes
How the screw cap works
The hot lid, heated over steam or in hot water at a temperature of no more than 60 C, is screwed on and fits tightly to the glass of the jar.
The polymer coating on the inside of the lid, which acts as a gasket (sealant), softens in heat and allows you to close the jar with the lid as tightly as possible, without gaps. As it cools, the top of the lid is pulled inward (a slight click is heard) and a dry vacuum effect is created inside the jar.
Rules for using twist-off caps
Do not tighten more than the thread allows, do not overtighten. Otherwise, you will break the lid.
You need to install the cover, getting into the thread, and screw it on these rails. Otherwise, cracks will form and mold may appear in canned food.
Close canned food with a lid immediately after filling the jars.
Do not overfill jars. The jars should be filled with contents as much as possible, but not reach 1 cm from the edge of the jar.
How to Store Screw-Lid Jars
Most canned foods can be stored with screw-on lids in a warm (but not hot), dry, and well-ventilated area. Do not expose canned food to sudden temperature fluctuations to avoid condensation.
However, if you can preserve jam with a small amount of sugar or compotes without sugar, or make other preparations that require more careful storage, they should be stored at lower temperatures (in the refrigerator or in the basement).
Before storing jars, jars with hot contents must be cooled to room temperature and checked for leaks (turn the jar upside down and see if the rim of the lid is wet).
The shelf life of canned food in screw-necked jars closed with screw lids is 6 months or more.
Lifespan of screw caps
Twistable, screw-on lids - reusable. If you handle them carefully and do not clean off the varnish and the polymer inner layer of the lid with a hard sponge, the lid will last 4-5 years.
If the cover is rusty, it is not suitable for further use.
How to tell if canned food with a screw cap is edible
When the can is first opened, a loud pop is heard - this means that the canned food has not fermented or swelled.
If you notice that the lid on the jar is swollen, the canned food is spoiled, it is poison, you cannot eat it.
How to open the lid
Screw caps can be opened by applying force and turning it in the opposite direction, or you can use a special opener for twist-off caps (they are sold in all hardware stores with a large assortment of products).
Which way to turn the lid
To close the screw cap, you need to twist it clockwise. To open, you need to unscrew the cap counterclockwise.
The lid does not open - what to do?
If the lid does not want to unscrew or you do not have enough strength, you should first try to cover the lid with a cloth or towel (so that your hands do not slip) and turn the lid.
If the technique is unsuccessful and the jar is still tightly closed, you need to take a burning match and slightly heat the lid from below with a flame (under the rim, around the jar). Just 1 match is enough, it’s quick, you won’t even burn your fingers. The lid will expand when heated and open (well, not by itself, of course, turn the heated lid).
Different types of lids: plastic (including nylon, translucent), plastic drain lid (with holes) and twist-off lids
Is it possible to replace simple preservation lids with screw-on lids?
Yes, you can preserve all types of salads, compotes, cucumbers, tomatoes or mushrooms in marinade under screw caps. That is, use them to screw all the workpieces that were previously rolled up with simple tin lids.
Twist-off lids come in different sizes internal coating(more or less resistant to chemical influences). And if you have a very acidic product in the jar (sour fruit compote, sour juice or marinade), then you better take the lids with a generous layer of varnish to protect the lid from interacting with acids.
Plain iron, plastic and twist caps
In addition, jams and preserves can also be covered with plastic - nylon covers, placing a circle of white paper soaked in vodka or alcohol under the lid (on top of the jam). The paper soaked in alcohol will collect mold on itself (if it suddenly appears) and you can throw away the damaged paper by placing a new piece of paper on the jam.
Nylon covers - the same plastic ones, only colorless
Jam cooked in a 1:1 ratio or if there is even more sugar in it (1:1.5 or 1:2) will be well preserved under a nylon (plastic) lid and at room temperature (but not in the heat, of course).
During the preparation season, it is important to stock up not only on food, but also on high-quality seaming lids, because they will help preserve the preparations throughout the winter.
To choose a glass jar you do not need any special knowledge: the main thing is to decide on the volume of the container and its convenient shape. But everyone involved in canning should know about the choice of lids for canning, because the success of the canning process will depend on the material from which they are made, their health safety, convenience and quality.Tin lids "SKO". These covers are familiar to everyone. Always in demand due to their low price. These lids fit almost all glass jars. Before you buy, pay attention to the internal coating - for a high-quality lid it should be varnished. If you decide to save on cost, you risk getting a terrible tin taste in the preparations, and even poisoning the body during long-term storage. To check the lid, you need to wipe the inner surface with a cotton pad soaked in acetone - if a yellow or green trace remains, the lid will react with the contents of the jar, gradually poisoning it. Be sure to purchase a seaming wrench if you don't have one, and don't use these caps over and over again. Do not buy tin lids “in reserve” - the shelf life of such lids is only 3 years.
Twist-off lids. Practical and convenient lids for reusable use, there is one requirement - they fit into jars with threads. It is advisable to check the lid before sealing for reliability. To do this, fill the container with water, screw on the lid and then turn it over. If water leaks, such a lid cannot be used; if not, it can be preserved. The main advantage of such lids is their affordable cost, no need for a seaming machine, and convenient storage after opening the jar. It is also advisable to check the varnish coating inside the lid.
Polyethylene (plastic) covers. Such lids are disposable; after placing them in hot water, they expand and are then put on the jar. It is recommended to store pickles with such lids in the cellar, but for jam you are unlikely to find a better lid in terms of price and ease of use.
Now you know which lids are best to choose for home canning. It is advisable to check all jars for chips and cracks before starting conservation. Also, don’t forget to buy these “saviors” to facilitate the sterilization process: a disc-stand for a pan and a grip for jars. Now you are ready! This means it’s time to start canning at home, because you won’t find such “goodies” in the store.
Signs of quality seaming caps
Ideal seaming lids are made of food-grade metal. In appearance, tin and aluminum covers are almost indistinguishable, but the latter spring back when pressed with your hand.
The lids suitable for seaming are coated with acid-resistant varnish. Preferably on both sides, but definitely on the inside! Otherwise, the metal will rust and ruin the workpiece.
Ideal seaming caps have a rubber ring that fits tightly around the circumference of the cap in a groove. Yellow tin lids resist oxidative processes. White, unvarnished, tinned, are only suitable for covering products with low acidity (jam, compotes, jam) and are not suitable for preserving brightly colored fruits and berries. Aluminum lids are used for all types of canned food.
Despite the fact that metal seaming lids are disposable, some housewives manage to reuse them. There are even tools designed to remove the covers with minimal damage. And yet, giving them a second life is undesirable for hygienic reasons.
If you don't remember when you purchased the lids, stretch the rubber seal around one of them. If it has retained its firmness and elasticity, the lids are ready to use. If not, throw it away: changes in temperature and humidity have done their dirty work.
Please note this:
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| All about garden plants | ||
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Very little time will pass - one or two months - and the annual folk entertainment “Operation Conservation” will start. Experienced housewives roll up everything that grows in the garden, garden and forest for the winter. Strategic reserves of cans and lids are assessed in advance, missing components are purchased, and even innovations in the field of blanks are purchased. On the eve of the season, it would be a good idea to remember familiar technologies or learn new ones.
To create canned culinary masterpieces, lids, glass jars and the necessary devices are used - seaming wrenches of various modifications, pumps, sterilization containers, etc.
Let's start with the lids. To preserve supplies, lids made of tin (metal) and polyethylene (plastic) are used. The most common and affordable are tin lids made by stamping. What should you pay attention to when using these caps? Firstly, such a cover must have a recess of sufficient depth for the rubber sealing ring; there should be no burrs or stamping defects along the edge of the cover. The inside of the tin lid must be coated with a protective varnish layer. You can check how high quality it is: moisten a cotton swab with acetone and rub the varnish surface. Acetone will not dissolve high-quality varnish. It is desirable that stiffening ribs be embossed around the circumference of the lid, this will allow the lid to increase its strength. Tin lids are recommended to be used once. Tin lids should be sterilized in boiling water for no longer than 3 minutes, otherwise the rubber ring may become deformed. The rubber in the lid should not break with a little effort. The lid fits the jar if, when placed hot on the neck of the jar, it does not move (there is no play). The shelf life of the tin lid is no more than 3 years and it should be stored in a dry place.
More convenient, which have earned the recognition of housewives, are the lids called “twist-off” (in English, unscrew), or in common parlance such lids are called screw ones. The lids are a little more expensive than regular tin ones, but they are quite affordable and can be used twice or thrice if used carefully. To check whether the lid will hold well, you can do this: pour water into a suitable jar (with a thread) and close the screw lid without much effort; turn the jar over onto a napkin. If drops of water do not appear on the napkin, then the lid will seal the jar securely. Twist-off lids are suitable for sealing all types of preserves. Close the lid on the jar while it is hot and with the contents of the jar still hot. Lids can be sterilized in boiling water. You can open such lids with a special key, or after heating the lid to t+60°, it can be easily opened manually. A special feature of the screw cap is the valve located in the center, which becomes convex if fermentation processes occur with the contents of the jar.
Polyethylene lids are used to seal mainly sweet canned food. These lids are thicker than regular ones. Being cold, they will not fit onto the neck of the jar; only when hot, they can easily fit where they need to be. Thermal lids (as they are also called) should be kept in boiling water for no more than 15 seconds to sterilize. The lid is usually marked “for preservation.” It is advisable to use thermal covers once, since polyethylene is often deformed and cannot provide a tight seal.
The newest, most expensive, most reliable and reusable lids are vacuum ones. The vacuum lid is a convex plastic dome with a valve in the center. The cover includes a pump connected to the valve. This pump pumps air out of the jar, thereby creating a vacuum in which microflora does not develop. Although the lid is not cheap, its cost is justified: the lid can be used 200 times. The vacuum lid can be sterilized in just a few seconds. Another good thing about this lid is that you can leave it on the neck of the jar (you took a few vegetables from the jar and pumped out the air again, the product does not spoil). These lids can be used on jars with or without cutting.
Some useful tips
1. Pay attention to the glass jar: if there is a noticeable “seam” along the jar, then such a jar is more likely to burst. The year of manufacture is stamped on the bottom of the can. If the jar is many years old, then it is better not to use it for preservation.
2. If there are visible glass chips on the neck of the jar, even small ones, then such a jar cannot be placed under the seaming key.
3. It is better not to preserve food in plastic containers; it is harmful to health.
4. An uncorked jar of pickles will be protected from mold and fermentation even in the refrigerator by ordinary pharmaceutical mustard plaster placed under a regular plastic lid (place with the mustard layer down).
Today we’ll talk about what types of canning lids there are and how to roll them up.
What types of lids are there for preserving in an autoclave and how to choose the best one
Today, 4 main types of lids are used for food preservation:
Tin lids
Classic canning lids that stand the test of time. Tin lids are very popular among housewives, even though they are disposable and are rolled up using a seaming machine.
Such a lid should be made of food-grade metal and coated on both sides with food-grade varnish. Lacquered lids resist corrosion and oxidative reactions from the marinade well. A lid made of white unvarnished tin cannot be used for seaming for a long period of time; the workpieces are likely to deteriorate.
Unvarnished lids are suitable for non-acidic products: preserves, jams or compotes. For salty preparations (vegetable marinades, sour berries and fruits), it is recommended to use coated lids. The fact is that unvarnished tin reacts with the acidic solution of the marinade and spoils the taste of the latter.
Screw caps (twist-off)
Convenient, reusable lids that have their limitations. For example, they are only suitable for sealing cans with threads on the neck. The advantages include their relatively low cost and the ability to roll manually without a seaming machine. Screw caps can be used several times, but you will do this at your own peril and risk: if the sealing ring on the inside is damaged, the workpieces will deteriorate.
What products are they suitable for?
Twist-off lids are suitable for all types of products. But like tin, they have different coatings on the inside. For compotes and jams, a regular lid is suitable, but for salted preparations it is better to use specimens with a varnished coating.
Plastic lids
This type of lid is almost never produced today, however, some housewives consider them the most environmentally friendly and airtight. They do not fit onto the jar without first heating it in boiling water, but they are quite easy to remove.
What products are they suitable for?
Plastic lids are perfect for preparations with a large amount of sugar, where there is no risk of excess pressure. To keep preserves and preserves longer, you can put a piece of paper soaked in alcohol under the lid. In case of mold formation, the paper will absorb everything, keeping the workpiece intact.
Caps with vacuum pumping system
A relatively new invention. They are reusable (manufacturers promise up to 200 seams) caps with a special valve and pump included. Their main disadvantage is their high price and inability to purchase in a regular store. But the use of vacuum lids quickly pays off, and the preparations retain their original aroma and taste throughout the entire shelf life.
What products are they suitable for?
The list of products that can be sealed with vacuum lids is long: vegetables, compotes, jellies, preserves, salted preparations, fruits, berries. This type can be safely called universal.
How to properly seal jars with lids for preservation
But it’s not enough to choose a high-quality lid for sealing. You still need to roll it up correctly. This technology is not very complicated, but it also has its tricks.
Tin lids and twist-offs First you need to soak it in boiling water. The rubber seal on the inside of the lid will soften and the jars will be preserved hermetically. After soaking in boiling water, the lids are removed, placed in the center of the neck of the jar and fixed: tin ones - with a seaming machine, twist-offs are simply twisted tightly by hand.
Plastic lids after 2-3 minutes of exposure in boiling water, screw it onto the jar. For reliable fixation, it is recommended to choose those lids that cannot be put on the jar without preliminary exposure.
Vacuum lids They have a slightly more sophisticated canning technology.
- First of all, we prepare glass jars and inspect them for chips and cracks.
- We wash the vacuum lids before use and place them in hot water for a couple of minutes.
- Fill the jar with food, place the lid on the neck, press the pump to the lid and make a few pumps. The cover will lock.
How to roll up jars? (video)
