How to make an autoclave for home canning

Preserving the abundance of your garden or local market through home canning is a great way to guarantee that you can savor summertime flavors all year long. While a lot of people use conventional techniques like water bath canning for fruits and pickles, a different strategy is needed for low-acid foods like meats, vegetables, and poultry. At this point, a pressure canner or autoclave is necessary. Commercial autoclaves can be pricey, though, so many people wonder if they can build one at home.

Although building a DIY autoclave for home canning may seem difficult, it is actually quite doable if you have a basic understanding of how pressure canners operate. Using steam under high pressure to reach the temperatures required for safely preserving low-acid foods is the fundamental idea behind an autoclave. Your canned goods are safe to store and eat because of this process, which guarantees the destruction of any potentially dangerous bacteria.

In the parts that follow, we’ll go over the essential parts for building a do-it-yourself autoclave, precautions to take, and detailed instructions to help you make the most of your do-it-yourself abilities. Constructing an autoclave can improve food preservation and bring a new and exciting element to your home canning experience, regardless of your level of experience with do-it-yourself projects.

Principle of operation – pressure cooking

The use of a household autoclave for canning allows you to engage in the household industrial technology of heat treatment of any raw products. The apparatus shown in the diagram below is a hermetically sealed metal tank with a pressure gauge, valve and air valve. It acts simultaneously as a sterilizer and a pressure cooker, reducing 2 time-consuming operations to one.

The instructions for the autoclave used in Belarusian production provide the technology for canning food, but homemade units can also use it:

1. Water is poured into the washed glass container to a level of 1-2 cm from the bottom.
2. The initial food product is mixed with spices and other ingredients according to the recipe, after which it is placed in jars and immediately sealed with lids.
3. The jars are placed on a pallet inside the container in several rows (directly on top of each other). Then the tank is filled with water to a level 60-80 mm below the neck. At that time the lids of the last row of dishes should be submerged by 1-2 cm.
4. The autoclave hatch is closed and screwed on, then pumped through the valve. The amount of overpressure inside the chamber should be 1-1.5 Bar (0.1-0.15 MPa).
5. The apparatus is heated on a gas stove or other way until the pressure increases to 3.5-4 bar. This indicator is maintained for a certain time required for the readiness of canned food (fish sprats are enough 20 minutes, chicken – half an hour, and beef stew will need at least 40 minutes).
6. The heating is switched off and the tank cools down to room temperature together with the jars, after which the air is vented through the valve and the unit is unloaded.

For reference, certain factory models lack a valve and pre-inflation features. However, under these circumstances, the steam pressure within the container weakens the lids, necessitating the needless inconvenience of using stainless steel ties to secure rows of jars.

The idea behind the autoclave’s operation for home canning is to raise water’s boiling point by applying more pressure inside the container. It boils between 98 and 100 °C under typical circumstances. This boundary will move to 120 °C if you create a surplus of 1 bar in a closed tank, and the temperature will rise to 120 °C at 1 bar. 5 bar, or nearly 127 degrees. As a result, vegetables (meat) are cooked more quickly, which also results in the eradication of all bacteria and viruses that could otherwise survive a normal boiling point.

Making an apparatus from a gas cylinder

One of the most dependable and affordable types of homemade autoclaves is constructed using an old propane cylinder. Its cylindrical shape, rounded ends, and metal walls that are at least 3 mm thick make it most suited for high pressure operation.

But you can also use other comparable items and materials to create the casing:

• air receiver from a truck or railroad car;
• industrial fire extinguisher;
• milk can;
• thick-walled black or stainless steel pipe.

Note: Some of the options on the list have clear drawbacks. The bidon’s bottom will need to be reinforced if the receivers were originally intended for air injection and were shaped similarly to the cylinder. The bottom of a regular pipe must also be massive to prevent it from being squeezed out during the heating process.

The most useful type of autoclave is made from a tiny gas cylinder that holds 14 half-liter or 5-liter jars and has a 24-liter capacity. The standard 50-liter vessel is too tall, making it challenging to use; you cannot place such a unit on a plate on the stove. In this instance, do-it-yourself artisans either use burners for heating or incorporate a TEN to turn the design electric, as we will explain below. The amount of canned food that can fit in each container is depicted in the diagram.

Old propane tanks can also be used for other practical home DIY projects. For instance, they can be used to weld a brazier or a wood stove with a long burn time.

Preparation for work

The following supplies and equipment must be ready before building a home autoclave: a drill, a welding inverter, and a bolgar. The metal components are next:

• 10 mm thick mild steel sheet – for making the seating flange and lid;
• the same, 5 mm – for the neck;
• 3 mm thick sheet or steel strip – for the can tray;
• Manometer and thermometer connections (if necessary);
• M12 bolts with nuts – 8 pcs.

A pressure gauge and safety valve, which release steam when the critical pressure is reached (on factory models, it is set to 5 bar), are additional safety and control devices that you will need.5 Bar). Since the pressure is the primary parameter that needs to be controlled, a temperature meter is not required.

Advice: Install a safety group, which is used for gas and solid fuel boilers in closed type heating systems, as shown in the photo to prevent multiple holes in the body or cover. Cover the air vent valve opening.

The standard car camera valve or the tubeless tire valve should be cut in order to generate excessive pressure inside the body.

Fabrication instructions

The drawing illustrates the most basic autoclave our expert created for canning straight from a gas cylinder. Here, a square flange is used instead of a round one since it is much simpler to make by hand. Steel strips are welded from the inside to the side walls to form the tray.

Important point. It was not by accident that the thermometer was placed in the center of the housing. This is because cooking takes place in garages, summer kitchens, or sheds a lot of the time. These rooms get chilly in the fall, and the thermometer on the lid starts to read 5 to 10 °C lower. In the video, the issue is explained in further detail:

The cylinder must be disassembled in accordance with all guidelines as the first step.

1. Unscrew the valve, put the vessel in an upright position and fill with water.
2. If the faucet can not be unscrewed completely, dismantle its brass part, as done in the photo. True, water will have to be poured through a hose with a tip, because the hole is too small.
3. Cut out a square opening for the neck according to the drawing and drill holes for the air valve and thermometer connection.
4. To get rid of the embedded gas odor, burn the container with a torch, blowtorch or on a fire.

As a point of reference. Because propane gas is heavier than air and will not escape the vessel on its own, even when placed horizontally or turned upside down, residue from propane is removed from the tank by displacement with water.

Additional assembly is straightforward:

1. Install the tray of iron strips and weld them together.
2. Make a neck from 5 mm thick metal and weld it to the cylinder.
3. Cut out the flange and the cover, then drill holes for bolts and the spigot of the manometer, fastening both parts with clamps.
4. Weld the flange to the neck and the threaded fitting to the manhole. Mount the safety group on it.
5. If you decide to provide temperature control, make a hole in the side of the case and install a second threaded pipe, screw on a thermometer.
6. Assemble the valve for air injection.
7. Make a rubber gasket according to the dimensions of the flange. This completes the assembly.

It should be noted that the safety group spigot’s location on the lid—it can be welded in the middle or on the edge—is irrelevant. However, the air valve needs to be positioned above the highest water level. The following describes how to create an autoclave out of a big fire extinguisher:

About electric sterilizers

Based on reviews found on forums, it appears that electric heating appliances are not very common; this can be attributed to rising conservation costs. After all, the tank’s strong heating components use between 2 and 4 kW of electricity per hour. On the other hand, an electric autoclave can automate the sterilization process if it is fitted with a thermostat and temperature sensor.

Note: In traditional technology, homemade devices with electric heaters are just as successful when using gas, a blowtorch, or even a campfire for heating.

The process outlined above is identical to that of creating an electric sterilizer. Installing the heating elements in the vessel’s bottom, as seen in the above photo, is the only extra step. The following video provides more details on the assembly procedure:

In this article, we"ll delve into the world of home canning and explore how to craft your very own autoclave for safe and efficient food preservation. Whether you"re a seasoned canner or just starting out, having the right equipment is key to ensuring your canned goods stay fresh and tasty. By following our step-by-step guide, you"ll learn how to assemble a simple yet effective autoclave using readily available materials and basic tools. From understanding the principles of pressure canning to creating a setup that meets safety standards, we"ll walk you through each stage, empowering you to confidently embark on your home canning journey. Get ready to preserve your favorite fruits, vegetables, and more with ease and peace of mind.

Rules of operation of the autoclave

The autoclave needs to be used carefully, just like any other vessel that runs at high pressure and temperature. All of the recipes in the books can be improved by adhering to these basic guidelines:

1. Pour water into the jars before loading the meat and fish, not afterward. We repeat that its level in the container should not reach 8-10 cm to the neck. If you pour more, the water will expand during heating and rupture one of the welds.
2. Constantly monitor the pressure and temperature by checking the table (shown below). Heat the unit quickly up to 100°C and then reduce the flame to just maintain the temperature.
3. The maximum pre-pumping pressure is 1.5 Bar, it is not allowed to do more.
4. Do not vent or open the autoclave immediately after turning off the heat. In this case, you will get mush with glass, because all the dishes will burst. Wait for cooling down and only then unload the ready canned food.
5. Release air slowly so that there is no pressure surge inside the unit.

Advice: A pressure gauge is the most effective tool for monitoring the cooling moment. The device can be opened safely once the vessel’s pressure drops to its starting point, which was after inflation. View this video to learn how to cook canned food:

One useful and satisfying way to preserve your favorite fruits, vegetables, and other foods is through home canning. You can make sure that your canned goods are safe to eat and have a longer shelf life by using an autoclave. You can build your own autoclave for home canning by following the instructions in this guide, and then you can enjoy the results of your labor for many months to come.

Safety must always come first when building an autoclave for home canning. Make sure the pressure and heat needed for successful canning can be handled by your autoclave by making sure it is made sturdy. While canning, make sure to double-check all connections and seals to avoid leaks or mishaps. Prioritizing safety above all else is crucial when using pressure canners.

In addition, when assembling your autoclave, precision is essential. Make sure you use high-quality materials that can withstand the heat and pressure involved in canning, and closely follow the instructions. It will pay off in the long run to take the time to build your autoclave correctly, as this will guarantee that your canned goods are safely preserved and free from contamination.

Finally, before using your autoclave for home canning, remember to test it. Try using water or low-risk foods in the autoclave to make sure it works properly and maintains the proper pressure and temperature. Knowing that your autoclave is operating correctly and prepared to safely preserve your favorite foods will give you peace of mind.

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