Friday, June 12, 2009

Are you canning food or just sealing your jars?

Time for a post on the difference between CANNING food and meerly sealing the jar (making it "ping" and the lid button go down.)

I just read a blog about canning and someone commented that they had an easier way to "can" salsa. Instead of putting the jars into boiling water (or using a dishwasher on the "sanitize" setting and keep them in there and hot), they put them on a tray in a 250 deg oven. They made up the uncooked salsa then put it into the jars, popped a lid and ring on, closed the jars and put the jars back into the 250 degree oven for 10 minutes?!??!!! That salsa wasn't even brought to a boil before it was "canned"!

Here is the comment that I left. Hopefully, others will see this on the blog in question and not try the suggestion of the other commenter.

re:xxxx's comment:


I took a Master Home Preserver course from the local extension office. One thing people don't seem to understand is the difference between a "sealed" jar and a "canned" jar.

ANY jar of hot food with a sound, dry, chip-free lip and a new lid put on it will normally SEAL. The heat will cause the compound to soften and when the pressure in the jar drops as the food cools, the lid will "ping" and the jar is SEALED. That does NOT mean the food is "safe". All it means is that the mechanical part of "sealing" has been done. This does NOT mean that there is no bacteria in the food, only that the jar lid is "glued" to the jar itself. Which means that any bacteria that is anaerobic (doesn't need oxygen)can multiply and poison you. Can we all spell botulism? These types of instructions are what give canning its bad name. People think the jar is "canned" after all, the lid "pinged" and then eat food that makes them sick.

CANNING is where you prepare food, put it in a jar, put a hot lid on a hot, sterilized jar and then HEAT THE FOOD IN THE JAR in a canner or pressure canner for a specific amount of time and in a specific way so that any bacteria that was in the food is killed. Acidic food can be "water bathed", any other foods need to be pressure canned with a pressure CANNER, not a pressure COOKER. (a big difference having to do with size of pot and amount of time not being correct for "caning" in a cooker.)

Water boils at 212 degrees, but it takes either an acid environment OR 240-260 degrees to kill some types of common bacteria, bacteria that are found in the normal environment that doesn't hurt us as long as the bacteria has to deal with oxygen. However, when we seal a jar, then the oxygen is gone and the bacteria multiplies and when it does, it excretes toxins. It's not the bacteria that kills or sickens you, it's the toxins that the bacteria releases. The only way to get water above 212 deg. is to put it under pressure - hence pressure canning.

Remember that we put meat in a 350 degree oven for several hours and only have meat that gets to about 190 degrees. Stuff put in a 250 degree oven for 10 mins doesn't get even CLOSE to 212 degrees, unless it was put in boiling first. But that STILL doesn't do the trick. Remember that in a water bath, 212 deg water is under, around and over the jars for 20-30 MINUTES FOR ACID foods ONLY. You should not even think about water bathing non-acid foods. Here again, yes, you CAN make the lids "ping", but it's STILL NOT safe!

Hopefully, at least the person who owns the blog and said she was going to try this method will read the post and chose to not try the oven "method of canning".


kelly said...

If you have an idea on how to preserve your foods then you have to apply it then. It would be great if you know how to do it.

twilight news said...

If you have any more way to preserve food,please let us know. i feel a problem while i preserve sweet in the freeze.

Cheryl Anderson (SwineInsanity said...

I personally think using the oven would cost to much to use to preserve... I am the type that investigates how things work for myself... but with the oven method, the energy to run it in itself does not seem worth it...

Darlene said...

I agree with you on that. Especially since it doesn't kill the bacteria that needs to die!

Somehow I let a comment through and then didn't answer it. I'm sorry!

Twilight news - there are several ways to nutritionally and safely preserve foods. We can dry, freeze or can foods. There are several ways of drying foods. Most foods can be dried and still taste good when rehydrated. The most common way to dry food is a dehydrator. You can also use the oven or the sun, though again, I think the oven would cost more than it's worth to use.
Freezing depends on what you're freezing. Some foods can be wrapped air-tight and tossed in the freezer. Some foods need to be blanched first to stop the enzymes in them.
Canning is either water-bath or pressure canned. Only ACID foods can be water-bathed. That would be fruits and pickles. EVERYTHING else needs to be pressure canned.
You can go online to uga.ed and download a preservation manual for free. It tells how to do home preserving. Also your local land-grant college (UGA, UF, etc) have county extension agents with free hand-outs.

Prepper12 said...

Hello,, I want to put dry foods such as rice, beans, pasta etc.. into jars and seal them?? how do I do that?

Darlene said...

I would make sure the jars are VERY dry. Add clean dry food item(s). Place a lid on the jar and tighten down the ring. Then dip the top of the jar, all the way past where the ring is on the jar, into hot paraffin wax (like "Gulf Wax", found near the canning/candy items in the store). The wax makes a seal around the jar top and keeps the air out.

You could simmer the lids like you do for canning. But then any moisture left on the lids even after you've dried it can cause molding in the food.

I had a friend in FL that used this method all the time to store cereals, crackers, etc. She opened a jar she had had for a year and it was still good. No staleness.

The other thing you can do is use a Food Sealer with the jar attachment and just suck the air out. I have a little hand-pumped dealy I got from an emergency/food storage place for about $10. It works just fine.

Darlene said...

And actually, you don't need to do anything more to beans than to put it into the jar and close the jar. The rice and pasta I might want to seal with the wax to keep bugs out of it. Bugs don't normally bother my dried beans.

The other thing you may want to consider is putting the food to be sealed into the freezer for 3 days. That way, if there are any bug eggs in it, the eggs are killed.

I'm fighting a pantry moth problem right now. The little nasties came home with me from the grocery store. sigh

*Mimi* said...

Is the oven sealing method ok for empty jars? I've never canned before and don't plan to, I just want to have sealed lids on my empty jars for projects.

*Mimi* said...

Is oven sealing ok if you want to seal empty jars? I've never sealed a lid, and I just want the jars for projects other than food preserving.

Darlene said...

I've never tried it, so I don't know. I'm going to say that it probably would work. I mean, it WILL seal, but I don't know if the glass will be ok. I THINK it will, but I don't know for SURE.

c976061 said...

what about jarring allready cooked meat would that last? say i cook up a bunch of ground beef, chicken, ect then seal it with a jar sealer would that be ok, should it be refrigerated?

Darlene said...


If you cook it and seal it with the jar sealer and keep it in the fridge, it will probably last a little longer than unsealed meat/veggie/produce/cooked grains would last in the fridge.

HOWEVER, it will NOT last on a shelf, unrefrigerated. Canning kills the bacteria that lives in the world and food around us. The reason you can not water bath can meats and veggies is that they aren't acidic enough to kill botulism - a VERY dangerous bacteria. You have to use pressure to get the water hot enough and then cook it long enough in that extra hot water to kill the botulism bacteria. Water in a canner can never get over 212 degrees (at sea level). To get it to 247 (I think that's the temp) to kill other harmful bacteria, you need to add pressure to the water. Just like using an autoclave to sterilize surgical equipment. In fact, a pressure canner can be used as an autoclave!

Before trying to preserve anything beyond using the fridge or freezer, I'd recommend you study up on the what, why and how foods can be preserved. Home canning is SAFE - UNLESS people don't follow the instructions EXACTLY. Home canning is not something you can just wing and be ok with. Once you've gotten some experience under your belt and understand the mechanics of canning, then you can sub out foods in a recipe because you'll know what foods can be substituted in the recipe and still be safe to eat. There are free sources out there to learn about canning.