No, they are not. It's a question of size. Pressure cookers are smaller. As a result, they heat up, and cool down, faster than a pressure canner. However, the heat up/cook down times are factored into the directions for any particular canning recipe. If you can in the pressure cooker the food will be underprocessed, and possibly unsafe. The bottom line is, you can cook in a pressure canner, but canning in a pressure cooker is not recommended.

Dare I say something in defense about a steam canner? I have used one for many years now and it uses about the same amount of water a pressure canner uses. It has proven it worth here by giving me many canned items that are not overcooked. I especially like it for jellies and pickles. Neither are difficult to can, or process. Because I add extra acid to both, safety issues are not a big concern. I had done many temperature tests on these, and have found that the recovery temps are quite fast, when it comes to the canning water coming to a boil again. As everyone knows, heat rises, cold drops. With room temp, water filled jars inside, and the canner water previously boiling, it can take at least 10-15 minutes for the canner to reach boiling again, even though the jars are not even touching the water. Also, the measurements I did were done with thermocouples and a device that is able to chart out 6 locations within an area. These temperature measuring devices are very accurate and when I had jars filled with water only, and measured the internal temps, they came up faster in heat than a boiling water bath. I am not saying a pressure canner is in the same class, as it is not. Pressure canners are used for low acid foods and offer higher processing temps above 212 degrees of boiling water. This is the reason for the high pressure used in a PC. The steam canner has a slight pressure when boiling, as it jets out a strong steam from just two tiny holes down near the water level. This indicates to me that the jars inside, are in fact exposed to something that is at least 212 and is under slight pressure. I measured an internal temp of 212 degrees inside a water filled canning jar after 10 minutes. That jar was filled with boiling water prior to the test however. I would never consider using this canner for any low acid products. For pickles, I prefer full 5% strength vinegar too. The jellies get an added acid blend of malic, tarteric, and citric acid.

Do you have a higher wire rack or some way to improvise one? I'm waiting for someone else to answer you, all I have ever found NCHFP is that the jars don't have to be covered for pressure canning, not that they cannot be. (To clarify -I don't specifically find where it says they must not be covered with water) I used to pressure can a variety of things in 1/2 pts for my little mother with a little appetite ;) - including tuna. I couldn't begin to process with less water with something that needed 100 minutes timing. Stacked, I could do three layers 1/2 pts in my 22 quart canner. That meant the bottom layer covered with water, or close to it. I didn't ever run into problems with siphoning, leakage, failure to seal. But I have no science behind my experience, I'm just letting you know I've done it without issues.

" But I see the steam canner I would need for my glasstop stove is about the same price as a pressure canner." That all depends on which brand and model of pressure canner you are looking at. Steam cannersa re for sale at Walmart for $37. You won't find a quality PC for that price. Brands are not all the same quality and you can do different things with different (more expensive) PC models. Plus there are PC models that cannot be used on glass top stoves and other issues with trying to pressure can on a glasstop even with the approved models. So it may not be a valid comparison. " since I read on here you can do same time as water bath at 5 lbs. pressure? I'm assuming the heating time would be about the same since both use about the same amount of water?" I'm afraid there is some misunderstandings here. While some deep models of PC can be used as a boiling water bath canner the jars must still be submerged and no pressure is used. "I read on here you can do same time as water bath at 5 lbs. pressure" would not be accurate or was taken out of context. Could you point to that comment? The overall processing time would end up being longer than the BWB time called for simply because you would have to vent and bring it up to pressure. That could easily affect the quality of some foods. Bottom line the only advantage to spending the money on a PC vs. a steam canner would be if you plan to actually use it for pressure canning. If all you can is high acid foods that would normally be BWB processed then the steam canner is the better deal IMO. Dave