Steam canners are rather obscure in the US--they have been mostly replaced by the more highly-researched Boiling Water Bath Method. The basic idea is to process jars of food in live steam rather than immersing the jars in boiling water. This method is ONLY for high-acid foods.
If you insist on using this equipment for canning, follow these rules to the letter:
- 1. Place appropriate amount of water in the base. Place the perforated cover over the base and bring water to a low boil.
- 2. Pack and fill jars. Secure lids firmly, but not over-tight. Set each full jar on the base and allow it to warm up while packing and filling enough jars for one batch.
- 3. When the last full jar has warmed up for 1-2 minutes, place the dome on the base and slowly (4-5 minutes) increase temperature setting of the stove until a column of steam 8-10 inches is evident from the small holes at the base of the dome.
- 4. Begin timing the process, maintaining the column of steam following the water bath canning recommendations adjusted for your altitude. Do not reduce temperature setting of the stove. The dome should not bounce from the base during processing.5. When processing time is complete, turn off the stove and wait 2-3 minutes before removing the dome. Remove the dome by turning it away from your face and body to avoid burns.
- 6. Allow jars to cool and seal. Remove metal bands and store the jars in a cool dark place.
Extension researchers firmly advise against steam canning low acid (e.g., vegetables) or borderline acid foods (e.g., tomatoes). Under-processing these foods can lead to botulism food poisoning.