I hope I understand your question correctly. If not please let me know.

Rhubarb is an acidic fruit that is BWB processed. I don't know the exact pH off hand but it doesn't require additional acid for canning safety. Since you are making jams the often seen call for juice of 1 lemon is for jel/set purposes and color retention, not safety.

Dave

Rhubarb has a pH of 3.1-3.4.

There seems to be a misapprehension about the use of lemon juice in many preserves. Except for a few fruits (i.e. figs, melons, bananas) or savory jellies such as pepper jellies lemon juice or other acid is not required for safety in sweet preserves.

Lemon juice is often added to improve the set, especially in traditional preserves without commercial pectin. To set a preserve needs a proper balance of acid+pectin+sugar and sometimes it can be difficult to achieve that balance.

Rhubarb is traditionally regarded as an "unreliable setter." It is often preserved in combination with other fruits higher in natural pectin.

If a rhubarb recipe calls for lemon juice it's to improve the likelihood of a good set.

Carol

I will trust you that it is acidic enough. I asked because it is not a fruit but a vegetable. Even though we treat it as a fruit in the kitchen.

Robin

It really isn't a matter of trusting us Robin. One need only check the tested and approved canning instructions/recipes for rhubarb.

Dave

Dave, A quick check of the recipes I had did not give me a definitive answer. Nor did the NCHFP website. (Until I just found the stewed rhubarb instructions there, oops).

Robin

Here is a link that might be useful: NACFP Stewed Rhubarb

You don't have to trust any of us. All you have to do is look at the FDA list of approximate pH. This is not infallible (ripe and green mangoes have been reversed) but it's a very helpful resource.

Carol

Here is a link that might be useful: Approximate pH of Fruits and Vegetables

You might want to try a rhubarb butter. I did some just like apple butter and it was wonderful. I cooked it down so it was pretty thick, almost like a jam.

I verified with a couple of people on this site that it is safe to waterbath.

Rhubarb butter sounds like a really great idea! That way I could maintain more of the tart flavor of the rhubarb by using less sugar then needed for it to set. I think given the temperatures this time of year I would use my crock pot to cook it down and not the oven ;-)

Thanks
Robin

In the end I made rhubarb ginger curd, so no canning possible anyway. I need to make 3 batches at least of the rhubarb apricot jam before i can play again to make sure I have enough.