What is
Pressure canning?
Pressure canning is the best method for safely preserving food. Safety means that during the canning process, all harmful bacteria are killed. This includes the botulism bacterium. By killing these harmful bacteria during canning, the food preserved in this way can be stored for at least one year. It's easy to store on the shelf and doesn't require a special freezer.
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Pressure canning is done with a special pot called a pressure canner. A canner resembles a pressure cooker, but there's one important difference: with a pressure canner, you can see on the pressure gauge how much pressure has built up inside. Knowing the pressure level is crucial for safe preservation.
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If you want to preserve low-acid foods like vegetables, meat, and fish, pressure canning is the only safe method.
You place the jars with the food you want to preserve on a special bottom plate in the pressure canner. Then you fill the pressure canner with 3 liters of water. Since a pressure canner works with steam, the jars do not need to be mostly submerged in water like with traditional canning.
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Then you close the canner. The canner comes with a weight that seals the steam valve. You do not place the weight on the steam valve at the beginning.
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You place the pot on the stove and set it to the highest setting. The heat will fill the canner with steam from the inside, pushing all the air out of the pressure canner. As soon as the water in the pressure canner boils, steam will come out of the valve.
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After 10 minutes, the canner will be evenly filled with steam from the inside. Then it is time to place the weight on the valve. Now the pressure in the canner will rise, and the temperature will exceed 115 degrees Celsius. This temperature is needed to kill all the bacteria.
After the appropriate canning time for the food in your pressure canner, you remove the pressure canner from the stove. While cooling, the jars will automatically vacuum seal. This works as follows: During heating, the contents of the jar expand, pushing all the oxygen out of the jar.
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When the jar cools, the contents contract again, pulling the lid down and creating a vacuum. This seals the jar airtight, preserving your canned food.
How does pressure canning works?
Botulism and canning
What is Botulism and why is it dangerous?
When is there danger for Botulism?
Of all the harmful bacteria that exist, the botulism bacterium is often discussed in connection with food. This is not without reason. Botulism is a serious, potentially life-threatening disease caused by the bacterium with the charming name Clostridium botulinum. Botulism can cause paralysis and even death.
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The most well-known form we know of is foodborne botulism. This occurs when food is contaminated with the bacterium and is not preserved safely. Improperly preserved food can create an ideal habitat for the bacterium.
The bacterium that causes botulism is fundamentally not dangerous to humans and animals. After all, the bacterium is present everywhere in soil and water.
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Normally, this is not a problem. The problem is that under the right conditions, the bacterium can form toxins. These toxins can cause paralysis and even be fatal.
The botulism bacterium thrives best in environments with low oxygen, moisture, and low acidity. These are exactly the conditions found in a vacuum-sealed jar with, for example, vegetables.
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When you do pressure canning, you cook under pressure. This raises the temperature so high that all bacteria are killed. For example, if you have preserved a jar of beets in your pressure canner and open it after a year, you can use it immediately, for example, for a salad. You don't need to cook it again before you can safely eat it.
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This is different from canning vegetables. If you open your jar after a year, you need to cook the food for at least 10 minutes to neutralize the toxins. And even then, you haven't killed all the bacteria.
Pressure: the Manometer and the Pressure Weight
When the lid is on the pressure canner, it is completely sealed. When the water starts to boil, the pressure canner fills with steam. This increases the pressure inside the canner, which raises the temperature in the pressure canner to over 115 degrees Celsius.
At this temperature, all bacteria are killed. The amount of pressure you need to build up to safely can something depends somewhat on the altitude at which you live.
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If you want to reach the correct temperature in your pressure canner, you need to take into account your elevation relative to sea level. Water boils at higher temperatures at higher altitudes. A lower boiling temperature is not effective enough to kill most bacteria.
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Germany
The minimum pressure you need in Germany to safely can, if you are using a pressure canner with a weight gauge, is 10 PSI. If you are using a pressure canner with a dial gauge, it is recommended to work with 11 PSI.
The CanMate has both, so you can safely can at 10 PSI.
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Higher than 300 m
If you live at an altitude higher than 300 m above sea level, it is important to work with the pressure required for your altitude. Below you will find a table indicating the pressure you need to use.
For example, if you live at 800 m, you need to increase the pressure in your pressure canner to 15 PSI if you have a pressure canner with a weight gauge, and to 12 PSI if you have a dial gauge. The CanMate has both, so you can safely can at a pressure of 12 PSI.
Pressure
Pressure canner with a pressure weight and/or a pressure gauge
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There are two different types of pressure canners:
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Pressure canner with only a pressure weight (weighted gauge)
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Pressure canner with a pressure weight and a pressure gauge (dial gauge)
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A pressure canner with only a pressure weight operates with a weight on the valve of the pressure canner. The weight vibrates at the correct pressure. If your pressure canner operates only with a pressure weight and has a 10-PSI weight, this weight will begin to vibrate and hiss at a pressure of 10 PSI. If you have a pressure canner with a 15-PSI weight, this weight will begin to vibrate and hiss at a pressure of 15 PSI.
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Depending on your altitude, you determine which weight you need to use. Once the weight starts to vibrate and hiss, you know that your pressure canner has reached the correct pressure, and you can start the timer.
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Our CanMate is equipped with a pressure gauge, on which you can read the pressure inside the pressure canner. You can easily tell when the correct pressure has been reached.
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It is important to have the pressure gauge calibrated every year to ensure it accurately displays the pressure. You can have this calibration done by companies, and you can search on Google to find out which companies near you offer this service.
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Our CanMate Presspan 22 qt is equipped with both a pressure gauge and a pressure weight. Our latest version comes with a pressure weight for 10 and 15 PSI.
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The advantage of having a pressure weight is that it is basically unnecessary to calibrate the pressure gauge every year. You simply wait until the weight starts to hiss and vibrate. Then you know immediately that the correct pressure has been reached.
Pressure Canning Step by Step
When you want to do pressure canning, first choose your recipe. You can use tested recipes from USDA resources. This is the United States Department of Agriculture, which is also responsible for quality standards. Here is the link for the recipes: USDA Complete Guide to Home Canning 2015 Revision.
Step by Step
01
After you have selected your recipe, you can get started. Make sure your jars are clean. Prior sterilization is not necessary, as this occurs during pressure canning
Clean top
02
Full the glass
Prepare your jars for filling. The easiest way to do this is with a funnel with a large opening. This ensures that the edges stay clean.
Leave the recommended space at the top of the jar. If all goes well, this should be included in your recipe. On average, this is 2.5 centimeters.
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Then take the time to fill the glass with a clear glass. Dadurch, die Luftblasen entfernt. It is important, that it is possible that the airflow will be entfernt. The air can function accordingly, as the product in the glass can be changed along with it. Deshalb möchten wir Luftblasen so weit wie möglich entfernen. With the pressure maintenance, the remaining air is automatically printed on the glass.
Airflow entfernen
04
Schraube den Deckel fest.
Clean the edges of your jars thoroughly. If you have used a good funnel, it is hardly necessary to clean the edges. When you work with food that is not too fatty or sticky, a bit of cleaning with a wet cloth will be enough.
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If you are working with greasy or sticky foods, vinegar can help you to degrease the rim.
Then take a clean dishcloth, put some vinegar on it, and then run it along the rim. It is very important that the rim is clean, otherwise the lid will not stick to the rim of the jar.
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Then screw the lid on hand-tight, but not too tight. If you tighten it too much, the remaining air cannot be expelled during pressure canning. Then air will remain in your pot, and you don't want that.
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When your jars are ready for canning, fill the pressure canner with 3 liters of water. It doesn't matter how many jars you have in it, it's always 3 liters of water. Be careful: if your jars are hot, fill the canner with hot water. If your jars are cold, fill it with cold water. Then place your jars in the CanMate.
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Check if the ring on your lid is properly seated and place the lid on the CanMate. Turn the heat up very high and wait until you hear steam coming out of the valve. The time this takes varies depending on the stove and whether you started with cold or hot jars.
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Once steam is coming out of the valve (and the pin in the right handle of the CanMate is lifted), reduce the heat slightly. You want to avoid losing too much moisture from the canner, which could cause it to dry out.
Full den Canner
06
Steam for 10 minutes and remove the weight
Then you should prepare a kitchen timer after 10 minutes. It takes 10 minutes to fill the pressure canner completely with vapor and air pressure. After 10 minutes you can quickly install the weight on the vent and the pressure.
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Wenn you work with a Canner with a dial-gauge work, keep an eye on the dial to see if your canner has the required pressure. When you work with a canner with only a weight-gauge, wait till the weight starts to vibrate or to hiss.
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Once you have the right pressure, set the timer for the desired end time. What you find out about your results. You should test the timer first, if necessary, the pressure is correct.
Press build
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Kühl und leer
Once your timer has elapsed, remove your canner from the stove and allow all the pressure to release. If your canner has a pressure gauge, you can see when the pressure gauge reads zero.
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If you have a canner with a pressure weight, the pressure is released when you no longer hear any hissing at all. Now you can remove the weight. Wait another 10 minutes before removing the lid. Then wait another 10 minutes before using the jar lifter to remove the jars from the canner.
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The cooling process should be gradual so that the jars are not subjected to a sudden large temperature difference. The contents of the jars are still very hot, and when it's that hot, the contents expand. If the area around the jar suddenly becomes much colder when removing the jar quickly from the canner, the hot contents want to be pushed out.
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This causes you to lose moisture from your jars, and some may get between the jar rim and lid, preventing proper vacuum sealing. So, let your canner cool slowly, waiting 10 minutes between each step to prevent it from cooling too quickly.
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Even if you are careful, it is possible to lose some of the contents of your jar. As long as more than 2/3 of the contents remain in the jar and the jar has been emptied, you can still store it in the pantry. If you lose more, it is important to refrigerate the jar after it has cooled and eat it first, even if the jar has been vacuum-sealed.
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Allow your jars to cool for 24 hours, then check if they have been properly vacuum-sealed. If you're using Mason jars, remove the ring and check if the lid is tight. You can lift it by the lid, and if it stays in place, the vacuum seal is sufficient.
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If you're using reusable screw-top jars, you can check if the lid is suctioned and makes no noise when pressed.
If you're using special weck-jars, you can check if the lid stays in place when lifted without the wire or clips attached to the lid. If your vacuum test goes well, the jar can go into the pantry.
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It is recommended to consume the contents of the jar within one year.
Storage
Pressure canning Cooking Times
