Wednesday, September 4, 2013

Pressure Canning the Summer Harvest

Whether you grow your own summer harvest, or just take advantage of the lower prices on fruit and vegetables in season, it makes sense this time of year to bring home fresh produce.

While you can eat some of it fresh, what are you going to do with the rest of it? Freezing comes to mind for most of us. But unless you have an extra large stand alone freezer, there is only so much that will fit in your refrigerator's freezer. I have heard people in the grocery store say, " I would get more if my freezer was bigger."  I just shake my head when I hear such things because, you can keep that produce (and buy a little extra) when you think outside the box and look to canning as as a solution to your food storage problem!

Last summer I wrote a post that provided an overview of water bath canning. This method of canning is used for high acid foods like fruits. You can see that post here. The method of canning needed for low acid foods like green beans, carrots, peas, or any kind of meat, is pressure canning.

Low acid foods require canning at a higher temperature than high acid foods. This is because bacteria is not destroyed at the temperature water boils (which is the temperature using in water bath canning). The bacteria clostridium botulinum lives in moist environments in the absence of air. This bacteria produces a spore that makes a poisonous toxin which causes botulism. You will need to heat the contents of a jar to 240 degrees to kill this bacteria. This can only be accomplished with a pressure canner.

So, If you have never pressure canned anything before, this post will provide an overview to give you an idea of how it is done. Please realize that what I am doing is providing an overview of pressure canning. I cannot possibly provide every detail you will need to do it correctly.  If, after reading this post, you decide that you are interested in trying it yourself, I recommend you get The Ball Complete Book of Home Preserving. It will walk you through each step necessary to correctly and safely pressure can foods for your family. My goal is to show you there isn't anything scary or magical about it. For this post, I will be canning green beans in a dial gauge pressure canner.

Green beans can be packed into jars raw or hot. I use the hot pack method because I believe you can get more into the jar. Let's start by preparing the beans. This year I grew Italian green beans. They are a flat bean that has a slightly sweeter flavor to them. Once picked and washed, I cut the ends off. Here is a picture.

Instead of 'snapping' these into pieces, I like to 'french' them. You should be able to find this tool anywhere. If not, you can buy one from Amazon.

They fit into the french cutter beautifully because they are so flat.

To hot pack them, add water to the pot to cover the beans and boil them for five minutes.

While the beans are heating up and boiling for five minutes, place clean jars into the canner. Add about three or four inches of water to the bottom of the canner, and turn the heat on high to boil. 

At this point, check the canner cover to make sure it is in good working order. I have a Presto Pressure Canner. The instructions state to inspect the sealing ring, vent pipe, overpressure plug, as well as the air vent cover lock seal before each canning session. 

Then attach the dial pressure gauge to the canner cover.

When both the jars and green beans are hot, pack the green beans into the jars leaving one inch headspace.

Then add the water you boiled the green beans in. If you pack raw green beans, you can just add boiling water here. Pack loosely so the interior of the jar can heat to the proper temperature. Run a bubble remover and headspace tool down the sides of the jar to remove any air bubbles.  I forgot to take a picture of this when I was filling the jars so I grabbed a picture from last year when I water bath canned peaches so you can see what I mean.

Once you remove the air bubbles, you are probably going to need to add a bit more water to the jar. Measure headspace accurately, it can ruin the seals if the headspace is less than what is called for. You can always add more headspace but never less. For example, as I mentioned above, green beans require a one inch headspace. That means you need to leave one inch space between the green beans and the top of the jar. In my green bean jars I usually have slightly over one inch headspace. I haven't had a seal failure (yet) in all the years I have been canning! Be sure to wipe the rim of the jar with a clean wet towel before putting the lid on it.

As you fill each jar, place it back in the canner. When all jars are finished, put the cover on the canner and lock it down. The canner needs to vent for 10 minutes before you put the pressure regulator on. This is really important. Not venting the canner can make the water in the jars 'blow out' into the canner. If this happens, you run the risk of the jars not sealing. Now, don't just put the cover on and start the timer. The steam needs to be coming out the vent pipe in a strong and steady force before you start timing. Wave your hand over the vent pipe. If you cannot feel a strong exhaust from the canner, don't start the timing yet. If the water was boiling in the canner before you place the top on, this won't take long. When ready, turn the timer on 10 minutes and let the canner vent. Once the 10 minutes are up, put the pressure regulator on. 

At this point, I highly recommend that you never leave the canner until you have finished processing your jars of food. If you walk away and forget about it, you can cause serious damage to your stove and kitchen if the pressure in the canner get too high. Stay right next to the canner so you can adjust the heat and all will be fine!

Everyone's stove is different so you may have to adjust the heat on your own stove differently than I do. The goal is to raise the heat slowly so the liquid in the jars stays there and doesn't 'blow out' into the canner. Here is how I regulate the heat:

When I put the pressure regulator on - the heat is on its highest setting.
When the pressure starts rising  - I turn the heat down to medium high.
When the pressure gets to 10 lbs - I turn the heat down to medium.
When the pressure reaches 12 lbs  - I turn the heat down to slightly below medium.

Green beans in quart jars should be canned at 11 lbs pressure for 25 minutes where I live. (Depending on your elevation - this could be different.) I can at 12 1/2 lbs pressure for 30 minutes. (I have always believed in slightly over processing.) I find when I regulate the heat as I described above, I don't have to make too many adjustments during the processing time.

However, small adjustments will be necessary to keep the pressure constant. (Just like the small adjustments you make when driving to keep your car on the road, you will need to make small adjustments on the heat to keep the pressure in the canner constant. Quick and extreme moves in the heat will contribute to quick and sudden pressure changes in the canner. This will result in 'blow out'. So, if you are noticing the pressure drop (it should be a small and slow drop), make small adjustments to the heat so it stops. Small adjustments to the heat will result in small adjustments to the pressure gauge as well. This will ensure the liquid in the jars stays there!

I feel that I should remind you that you won't be able to constantly monitor the pressure gauge if you walk away from it. Let's say for example, your pressure hits 11 lbs and you turn the timer on to process for 25 minutes. Now, if you walk away from the canner, and the pressure drops to below 11 lbs (even for just a few minutes), you can't continue to process the food for the time remaining even if you turn the heat up to get the pressure back to 11 lbs. Instead, you will need to bring the pressure back up to 11 lbs first, and then start the timer over at 25 minutes. So, I am serious when I say don't leave the canner. I get a chair and sit right next to the canner so I can watch it. I may bring a book with me, or work on the computer while I can. However, I usually look up at the pressure gauge two to three times a minute. 

Once the 25 minutes (30 minutes for me) are up, turn the heat off. Now, you can walk away from the canner if you want to. It will need to cool on its own until the pressure in the canner is back to zero lbs. Don't try to cool the canner quickly, it will result in a 'blow out' (or worse - damage to the canner and/or your kitchen)! Let the canner cool on it's own. Mine takes about 45 minutes.

When the pressure shows at zero and the air vent cover lock drops, take the pressure regulator off. Set the timer for 10 minutes, once you take the pressure regulator off. The air in the canner needs to adjust to the temperature in your kitchen before you take the cover off. After 10 minutes, you can take the cover off and remove the jars. Place them on a towel. This is to keep them off of the counters. Place them somewhere where there isn't a draft as well. The reason both of these are important is because you don't want the jars to crack or burst while cooling. Coming right out of the canner, the jars are still extremely hot. And as everyone knows, very hot glass put in contact with a cool surface, will break.

When the jars have cooled,  wipe them down to remove any residue and label for storage.

 There you have it! Produce canned safely at home!

I also would like to mention here, that I am not happy with my canning process because to can in my kitchen requires the use of electricity. It also heats up my house. I don't want all that heat in my kitchen in the summer, so I have been researching how to take the canning process out to the back yard. After much research, I have purchased this.

It mentions right on the package that it is recommended for home canning. It has great reviews and I know someone who cans on one. However, my canner specifically states in the owners manual NOT to can outside on a propane stove. So, I have been hesitant to try it. Apple season is here, so I think I will try water bath canning apples first. I also am going to research other canners to see if they can be used on a propane stove. Although I do like my Presto Pressure Canner, because of this issue, I cannot recommend this item for purchase. I also won't recommend the Camp Chef Pro 90 until I try it myself! Look for a review on how it went with the apple canning soon.

However, I do recommend The Ball Complete Book of Home Preserving and The Ball Blue Book, Guide to Preserving. I own both and love them. I have used recipes out of each of them. Both cover the canning process in detail and tell you everything you need to know to both water bath can and pressure can. If you decide to purchase either of these books, or anything else I recommend, I ask that you use my links to do so. It doesn't cost you anything to do so and I get a few pennies to help support the blog.

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