Keep in mind this is my experience selecting a pressure canner.
My first pressure canners were a matching pair of Presto canners that I scored used at a garage sale. I had stand over the stove and watch the gauges. I found this to be a tedious task.
Enter the bad ass, 30-quart All American 930. Of course, a 941 would be even better but it wouldn't fit in the space between the stove top and the venting hood. Sad.
If you listened to Pressure Canning: Not Bombs, Food!, you know that I scored my 930 on craigslist. I searched for nearly two years. I suppose in retrospect I could have simply bought one for the time invested in the hunt. It's always cash or time folks, cash or time.
Anyway, my 930 was delivered to my doorstep, brand spanking new! $200 Never used!
Dial Gauge v.s. Weighted Gauge
There are two types of pressure canners: dial gauge and weighted gauge. Presto canners are dial gauge canners. All American is a weighted gauge canner.
Dial gauges require careful attention the the dial and adjusting the heat to maintain pressure throughout the processing time. If the pressure falls below the required pressure at any time during processing--the processing time must be restarted. The dial gauge must be inspected and tested every year--including before it is used for the first time. A tester can be purchased so that you can do this testing yourself.
Why some folks prefer dial gauge pressure canners: At higher elevations the recommended processing pressure is lower compared to weighted gauge pressure canners--which does affect the quality of the final product albeit just a tad. Dial gauge canners are lighter weight and are less expensive compared to weighted gauge canners.
Why some folks prefer weighted gauge pressure canners: Of course, never leave your pressure canner unattended--but you can busy yourself with other kitchen tasks and just listen for the required jiggles. The dial confirms the pressure in the canner. No annual check-up required.
Keep in mind that both types of canners have overpressure plugs, vent holes, and gasket or metal-to-metal seals to inspect prior to use.
So, what's a canner to do? I recommend stepping over the dial gauge canners and opting for an All American canner.
The biggest downside to an All American canner is the price. And All American canners are heavy and the larger models are tall--making them cumbersome and tough to store away.
Considering the downsides, I still recommend All American canners.
What size? 921, 930, or 941. Okay, back up, what about the 910 and 915? If you are canning to stock up the larder it will take longer with a smaller canner. I've seen a 910 in action and it is cute, perfect for a small batch. The 915 is just as cute.
And what about the 925? Well, it accommodates the same number of jars as a 921. If you are using it as a pressure cooker, you might want the additional space. Keep in mind it is aluminum and you might not want to cook in it.
921: You plan to can using mostly pint jars or smaller jars--you'll be able to double stack pints but not quarts. Capacity 19 regular mouth pints or 7 quarts.
930: You are serious about home canning. You have a garden, you fish and/or hunt (or people you know fish or hunt), you buy apples by the bushel, and so forth. You'll be able to double stack quarts. You want to have a well-stocked larder in fewer batches. Capacity 19 regular mouth pints or 14 quarts.
941: You are serious about home canning and you have the stove to accommodate it! Go for it! Capacity a whooping 32 regular mouth pints or 19 quarts.
Be safe and eat well!
***Update 28 November 2015***
In response to questions regarding other pressure canner brands.
Mirro pressure canners: Mirro pressure canners are weighted gauge canners. I like weighted gauge canners but I also like having the dial gauge. The dial gauge allows me to confirm the temperature inside the canner and this is super helpful when the processing time has ended. I found that I prefer the weighted gauge with a dial gauge enough to not use the Mirro canner at all so I found it a new home.
Presto pressure canners: Again, it is my personal preference to have both a weighted gauge and dial. Presto canners get the job done and for years I used only Presto canners. Every year the dial gauge must be checked and if you are a serious canner then you should have the dial gauge checked more often. But, as I mentioned above I found regulating the heat applied to keep the pressure spot on to be a tedious task. Presto canners can be used with a glass top/smooth surface range which is a huge bonus if you have that type range! All American pressure canners are not recommended for smooth top stoves. Many folks report no problems using an All American canner with a smooth top range but I've seen cracked glass tops and counters from using an All American canner. Presto canners are terrific and get the job done while being affordable.
Granite Ware pressure canners (manual): I have no personal experience with Granite Ware pressure canners. The price is certainly favorable as you can score it for a tad more than fifty bucks. If the choice is between pressure canning and not pressure canning, perhaps this is a good choice for you. However, I would be disinclined to recommend this product as it is made in China and doesn't have the secondary visual confirmation of the pressure via a dial gauge.
Fagor pressure canner (product information page): I have no personal experience with Fagor pressure canners. This pressure canner only has two options: 8 pounds of pressure or 15 pounds of pressure--which seems less than lovely. The capacity of the 10-quart model is a 4 quarts which is fine if you are canning super small batches. Production facilities are located in China as well as several other countries. Overall, based on it's limited capacity and odd offering of 8 pounds of pressure, I am disinclined to recommend this pressure canner brand.
- Kansas State Research and Extension, Preserve it Fresh, Preserve it Safe.
- University of Wisconsin-Extension, Safe and Healthy: Preserving Food at Home
- USDA, National Center for Home Food Preservation, Complete Guide to Home Canning (2009 version)
- Utah State University Extension, Food Preservation Fact Sheets
- Mirro pressure canner manual
- Presto canner manual, 23-quart & 16-quart (Contact Presto for annual inspection of the dial gauge, contact your local extension office, or purchase a tester.)