[LotuSeed]

Ummmm most standard pressure canners DO have a gauge. They are either dial gauge or weighted gauge. Mine is considered a weighted gauge. It  has a dial that indicates internal pressure but this is not the sole indicator of pressure as would be the case with a dial gauge canner.  For a weighted gauge canner, the pressure regulator weight (5,10,15lb) goes on top of the vent pipe and jiggles during processing. On a dial gauge canner, a counterweight goes on the vent pipe but does not jiggle so the only way to tell the pressure is by reading the dial (some companies sell counter weights to use instead of the standard one).  The dial on my All American model is used only as a visual reference as the regulator weight jiggling indicates the actual correct pressure and that it has been reached and is being maintained.  There is also an overpressure plug that will automatically vent if for some reason the vent pipe were to become blocked (causing an unsafe increase in pressure). MODERN canners have overpressure valves to avoid "blowing up". Venting prior to adding the weight expels air inside the canner. If air is trapped inside the canner (resulting in air pockets) it can cause the internal temperature to be lower than required for safe processing low acid foods (240F).  Having dial gauge canners checked every few years is recommended as a means of ensuring accuracy and thusly, safety. The link below is to a reputable source that discusses the safest and most up to date methods available in the U.S. 

http://nchfp.uga.edu/publications/uga/using_press_canners.html
As for the difference between a canner and a cooker, is the capacity (it should be able to hold 4 quart sized jars) and the ability to accurately and consistently regulate temperature. 

Edited for clarity

[Snoop]

Perhaps I haven't used the right terminology. When I said gauge, I meant the dial that reads the level of internal pressure.

The Fagor doesn't have a dial. Its operating pressures are just over 11 psi and 15 psi. It can be vented.

Beekissed, do you always can at 15 lbs regardless of what it is you're canning (fruit or meat, say)?

[Annen]

It sounds the same as mine.  It has a weight of 5,10 or 15lbs pressure, with a safety plug which blows if the pressure is too much. It may be that the pressure scanners you have have heavier gauge metal than the ordinary pressure cookers. It has the same adjustments for altitude as you mentioned too.

[LotuSeed]

Sorry Snoop, my reply was in reference to the comment "most pressure canners do not have a gauge".

Annen Mirro and I think Presto, make canners that are lightweight and fairly thin and I believe they require a rubber or silicone gasket that creates an airtight seal when the lid is placed on and twisted into position. All Americans are much thicker by comparison, made of cast aluminum, and require no gasket. The seal is metal to metal. The lid hooks into position when turned and then tightened down with wing nuts. The same company also makes sterilizers (which are used for an entirely different purpose.) The thinner ones are lighter, but the gaskets have to be replaced periodically. The All American doesn't require a gasket but it's considerably heavier. The modeli have weighs 25lbs empty.

The regulator you have sounds similar to my setup and the booklet that came with it also has different processing times and weights depending on altitude and food type.
I only use mine as a canner and most recipes usually call for the 10lb weight, but there is usually an option to increase the weight (increase in temp) and decrease processing time. I don't think I've ever used the 5lb one and rarely use the 15.

[Beekissed]

Perhaps I haven't used the right terminology. When I said gauge, I meant the dial that reads the level of internal pressure.

The Fagor doesn't have a dial. Its operating pressures are just over 11 psi and 15 psi. It can be vented.

Beekissed, do you always can at 15 lbs regardless of what it is you're canning (fruit or meat, say)?

Snoop, I don't can fruit in a pressure canner....about the only thing I can in the pressure canner is meat and it requires the 15 PSI, so I go with that. 

Yep, the more expensive canners may have a dial but the dial gauge isn't needed at all for successful canning, so no need to have one.  Just using the correct weight for the right foods seems to be adequate. 

[LotuSeed]

Using weight higher than necessary can cause over processing, which means mushy food lol. Fruits are usually processed in a boiling water bath, meat, poultry, fish, legumes and other low acid foods are processed in a pressure canner.  Those are the most up to date methods recommended for safety purposes based on science, current technology and lots of research and testing.

Using a pressure cooker to cook food for immediate consumption is different than canning food in a canner for later use. 

[jambop]

Having worked in the scientific field , molecular biology, I have some knowledge of this sort of thing. I would have no hesitation in using a good pressure cooker for the sterilisation of tomato passata indeed I would have no hesitation in using a boiling water method for tomato passata and even things like ratatouille... and no I don't add lemon or citric acid. It is all about confidence and knowledge but Italian and French country people have been conserving food by this method for years the secret is knowing the right amount of time to give the processing.
I know people here who can meat products with a boiling water bath and they can eat the food in the jars over a year later. The point is most of what people conserve is cooked before it goes into the jar in the first place it is then sterilised after that.

[Beekissed]

Yep...I've done meat in a boiling water bath, just to see if it can be done.  It can...even raw packed.  The old mountain folks in this state have been doing all foods in a boiling water bath for generations without fear of contamination or illness because they have confidence in their methods and hygiene when canning. 

[Snoop]

Jambop, have you ever seen these in use in France?

http://www.mcm-europe.fr/en/120-sterilizers-and-pasteurizers-weck

I understand you can even bottle patés, terrines and thick soups with them, which is something Americans don't can.

If you have seen these devices, could you give me any advice? We can't run a freezer, as we have a solar set-up for electricity, but I could run a generator to power one of these sterilisers from time to time. A pressure canner would solve the problem of power (I could use gas) during the actual canning, but in terms of the things that can be bottled, I think one of these sterilisers would better suit our requirements.

[jambop]

Yes seen those snoop but these are not a pressure vessel! They are simply an electric water boiler into which you put the jars of food to be preserved. I use what most other French people use which is a galvanised bucket with a lid and column onto which you fix the jars. It can hold up to 11 litre jars or smaller ones. The bath is filled to re required level then brought to the boil with a gas heater put the jars in and bring back to the boil and then boil for the required time. Essentially you can use any large stock pot with a gas ring and butane gas bottle. The boiling water method is a very useful way of doing home preserving. The whole thing is down to knowledge and cleanliness there are load of vids on youtube.

[Snoop]

Thanks Jambop. I realised they weren't a pressure vessel. Do you can soups using your method?

[jambop]

Snoop you can preserve anything using the boiling waterbath method provided you do it properly observing the correct time at the right temperature. People have used this method for god knows how long I do not want to be unkind but all the rot you hear about using pressure canning methods and low acid food problems comes out of America where the FDA have to give all sorts of guidelines because of litigation against equipment manufacturers. If you know what you are doing and make sure you use clean jars and new seals every time and boil for the correct time then you have no problems with anything. I have to say I don't do meats but soup, pasatta and vegs are no problem.

[New shoot]

Snoop you can preserve anything using the boiling waterbath method provided you do it properly observing the correct time at the right temperature. People have used this method for god knows how long I do not want to be unkind but all the rot you hear about using pressure canning methods and low acid food problems comes out of America where the FDA have to give all sorts of guidelines because of litigation against equipment manufacturers. If you know what you are doing and make sure you use clean jars and new seals every time and boil for the correct time then you have no problems with anything. I have to say I don't do meats but soup, pasatta and vegs are no problem.

It is an age old tradition to preserve all sorts of food using the waterbath method Jambop.  As you say, hygiene and knowledge are the key, but this subject has come up on here fairly recently and there are very different opinions on it.  I for one did do a bit of reading up on it.    There is a chance that botulism can already be present in the food and in low acid canned or bottled items, it can then start to grow.   A normal waterbath does not kill it as it is not hot enough.

As you say, people have done the same for years with no problems at all, but it is up to the individual to decide for themselves.  If you are confident you know what you are doing, then fine, but if you prefer to pressure can some items, then it is a valid choice as well 

[Beekissed]

I understand you can even bottle patés, terrines and thick soups with them, which is something Americans don't can.

Eh?  Americans can up thick soups all the time.     I've got several jars of "thick" soup base sitting on my shelf right now.  We'll can up most anything, given the chance.   

[Snoop]

Eh?  Americans can up thick soups all the time.     I've got several jars of "thick" soup base sitting on my shelf right now.  We'll can up most anything, given the chance.   

Well, that's interesting Beekissed. I thought official advice in the States was no canning thick (dense) soups because of the possibility that the stuff at the centre of the jars won't get sufficiently hot to guarantee safety.