The situation when a loud bang is heard in the middle of the night and the contents of the refrigerator compartment scatter across the shelves is familiar to many housewives. This is not just an unpleasant surprise that requires time-consuming cleaning, but also a potentially dangerous event that can damage the internal equipment of the unit. Most often, glass containers with homemade preparations, salads or sauces left for storage become victims.
The physics of the process of destruction of containers lies in changes in the internal volume of the contents and pressure. Glass is a strong material, but fragile and lacks elasticity. When internal pressure forces exceed the tensile strength of the vessel walls, instantaneous destruction of the material structure occurs. In the confined space of a refrigerator, the consequences of such an event can be large-scale.
In this article we will analyze in detail the main reasons leading to explosions of cans at low temperatures, and consider the influence of chemical processes and temperature conditions. Understanding these mechanisms will allow you to avoid food spoilage and protect your equipment from failure. We will also discuss which types of containers are most vulnerable and how to properly organize storage space.
Physics of the process: expansion of liquids when freezing
The main reason for the destruction of glass containers at low temperatures is the unique property of water. Unlike most other liquids, water begins to expand when cooled below +4°C, and when it turns into a solid state (ice), its volume increases by about 9-10%. If the jar is filled to capacity and tightly closed, the ice simply has nowhere to go except to break the walls of the vessel.
Critical point occurs when ice crystals begin to form at the walls and gradually move towards the center of the container. The pressure created by the growing volume of ice can reach colossal values that ordinary food glass cannot withstand. The risk is especially high for containers with a narrow neck, where an ice plug forms most quickly.
It is important to consider that the rate of freezing also plays a role. If you place a hot or warm jar in a freezer or on a shelf with a very low temperature, a strong reaction will occur. The outer walls cool and contract instantly, while the inner contents are even hotter and expand. This voltage difference often leads to cracks even before active ice formation begins. thermal shock. The outer walls cool and contract instantly, while the inner contents are even hotter and expand. This stress difference often leads to cracks before active ice formation begins.
⚠️ Attention: Never put hot workpieces directly into the refrigerator. Allow them to cool to room temperature to avoid thermal shock and disruption of the compressor operating temperature.
There is also the concept of “supercooled liquid”, when water remains liquid below 0°C until shaken. A sudden movement or opening of the door can provoke instant crystallization of the entire volume of liquid, which is guaranteed to lead to an explosion of the can.
Chemical processes: fermentation and gas formation
The physical expansion of ice is not always the cause of the disaster. Often the culprits are biochemical reactions occurring inside the preservation. If microorganisms entered the jar that were not destroyed during sterilization, or if the concentration of preservatives (vinegar, salt) was insufficient, the fermentation process begins. As a result of the vital activity of bacteria and yeast, carbon dioxide is released. In a hermetically sealed container, the gas has nowhere to escape, and the pressure inside the can begins to increase. Even in a refrigerator, where processes are slowed down but not completely stopped, the accumulation of gases can take days to weeks. At some point, the pressure exceeds the strength of the glass or breaks the lid. fermentation.
As a result of the activity of bacteria and yeast, carbon dioxide is released. In a hermetically sealed container, the gas has nowhere to escape, and the pressure inside the can begins to increase. Even in a refrigerator, where processes are slowed down but not completely stopped, the accumulation of gases can take days to weeks. At some point, the pressure exceeds the strength of the glass or breaks the lid.
The following are especially at risk:
- 🍅 Tomato sauces and juices with low acidity.
- 🥒 Cucumbers and mushrooms canned in violation of technology.
- 🥗 Salads with added oil, which creates a film that prevents the access of oxygen, but favors anaerobic bacteria.
- 🍯 Jam or compotes cooked with insufficient sugar.
If you notice that the lid on the jar is swollen (the so-called “bombage”), Do not open it suddenly or try to taste the contents. This may be a sign of the development of botulism, a deadly infection. Such blanks must be disposed of immediately.
The influence of temperature conditions and storage zones
Modern refrigerators have a complex air circulation system and different temperature zones. Improper placement of products can be a risk factor. In most models, the lowest temperature is kept on the back wall and on the top shelves (depending on the type of cooling - static or No Frost). This is where the risk of freezing of liquid products is maximum.
Freshness zone (zero chamber) is designed for storing products at a temperature of about 0°C. Placing containers of water or liquid sauces in glass containers there is dangerous, since even a slight fluctuation in the thermostat can drop the temperature below freezing. For such products, it is better to choose the middle shelves, where the temperature is most stable and is +3...+5°C.
In refrigerators with a system No Frost the air is drier and circulates more actively. This can result in moisture freezing out of food more quickly, but also in sharper temperature changes when the door is opened frequently. In such models, it is important to monitor the tightness of the seals.
The table below shows the approximate distribution of temperatures in different zones of a standard refrigerator:
| Storage area | Average temperature | Risk of freezing | Recommended products |
|---|---|---|---|
| Top shelf | +3...+5°C | Low | Ready food, drinks |
| Middle shelf | +4...+6°C | Minimum | Dairy products, sausages |
| Bottom shelf (above the drawers) | +2...+4°C | Middle | Raw meat, fish |
| Rear wall | 0...+2°C | High | Not recommended for glass |
| Door | +5...+10°C | Absent | Sauces, drinks, eggs |
Container defects and mechanical damage
Often the reason lies not in the contents, but in the condition of the container itself. Microcracks, chips on the neck or internal glass defects (air bubbles, uneven wall thickness) are points of stress concentration. When temperature or pressure changes, it is in these places that destruction begins.
Using mayonnaise jars or other industrial products for home canning is a common mistake. Such containers are made of thinner glass and are not designed for prolonged heat treatment or storage under vacuum for a long time. Their structure is less uniform compared to specialized jars for blanks.
It is also worth paying attention to the quality of the lids. Deformed threads or damaged rubber seals may allow air to leak, causing product deterioration and subsequent gas formation. Or, on the contrary, the lid may “stick” so much that when you try to expand the contents, it will not work as a valve, and the glass will burst.
⚠️ Attention: Before storing, carefully inspect each jar against the light. Any, even barely noticeable, crack at the bottom or rim of the neck is a reason to refuse to use this container.
Errors during preservation and storage
The human factor remains the main cause of problems. Violation of the preparation technology creates ideal conditions for an explosion. Insufficient sterilization, small amounts of acid or sugar, the use of low-quality ingredients - all of these affect the stability of the product.
Leaving is critically important air cushion (free space) when rolling. It is usually recommended to leave 1-2 cm to the edge of the neck. If you fill the jar completely, with any expansion of the product (thermal or freezing), the pressure will increase instantly. It is also dangerous to close the cans too tightly, preventing the micro-valves of the lid from operating during pressure changes.
☑️ Check before closing the refrigerator
Another mistake is storing open preserves in metal containers. If you open a can of canned food (sprats, peas, corn) and decide to put the leftovers in the refrigerator directly in the tin, the metal may begin to oxidize. The product changes its taste, and in rare cases, the lid may swell due to a chemical reaction between the acid of the product and the metal.
It is better to immediately transfer the contents of opened metal cans into a glass or plastic container with a lid. This rule is especially true for products with high acidity, such as tomato paste or pickled vegetables.
What to do if the jar exploded: algorithm of actions
If trouble has already happened, the main thing is not to panic and act consistently. The first thing to do is unplug the refrigerator. This is necessary for safety, as the liquid could get on the electrical contacts or damage the wiring.
Then you should carefully remove all large glass fragments. It is better to do this with thick gloves. After removing large fragments, thoroughly wash the shelves and walls with warm water and detergent. Pay special attention to the rubber seals and the drain hole (if there is one inside the chamber) - small fragments or sticky product residues could get there.
How to remove odor and glass residues?
To remove odor, use a solution of baking soda or activated carbon. To make sure that there are no small fragments left, wipe the surfaces with a damp paper napkin - the glass will catch on the lint.
After wet cleaning, leave the refrigerator doors open for several hours (or a day) for complete drying and ventilation. Only after making sure that the inside is dry and there are no foreign odors can you turn on the unit and load the products. If the exploded product was toxic or had a strong odor, the washing procedure should be repeated.
In conclusion, it is worth noting that following simple rules of production and storage hygiene reduces the risk of explosions to a minimum. Use high-quality containers, monitor the temperature and do not overload the shelves. Your refrigerator will last longer, and food will remain safe for consumption.
Frequently asked questions (FAQ)
Is it possible to store jars of water in freezer?
It is strictly forbidden to store glass jars completely filled with water in the freezer - they will burst. If you need to freeze water or broth, leave at least 15-20% of the volume empty or use special containers for freezing.
Why do jars of cucumbers explode in winter?
In winter, sluggish fermentation processes can continue in jars. If the cucumbers were poorly washed or there was little acid, gases accumulate gradually. An explosion can occur at any time when the pressure reaches a critical mass, regardless of the season, but often this happens during temperature changes (for example, when defrosting a refrigerator).
Are the contents of an exploded can dangerous?
Yes, it is dangerous not only because of the fragments, but also because of the possible content of toxins (botulinum toxin is odorless and taste). If a jar explodes due to bacteria, the product must be disposed of and the explosion site must be thoroughly disinfected.
What temperature is considered critical for glass?
Glass begins to experience severe stress when there is a sharp temperature change of more than 40-50°C. However, the danger is not so much the temperature itself, but the difference between the temperature of the glass and the contents, as well as the internal pressure when the liquid freezes.