If you use pomona pectin or the low/no sugar pectin from Ball, you can sweeten (or not) with whatever you want.

Deanna

Deanna - Isn't rhubarb really a veggie, not a fruit (except by law) and what is the ph of it. When making jam or canning do we need to add acid like lemon juice even when using Pomona?

pH of rhubarb is 3.10 - 3.40 so it's sufficiently acidic and is always treated as a fruit for purposes of canning.

Dave

While it is safe, you may want to do a comparison "test" of frozen vs. canned to see which you prefer long-term.

Sugar does offer its own preservative qualities, so without some level of sugar you're likely going to experience changes in texture, color and flavor over time on the shelf. Sweetness can be introduced with other ingredients, but unless you use honey or other natural equivalents you will find there are some other losses.

Also, you might want to try small batches with sucralose or alternatives and see if there are issues over time with bitterness.

Carol