I have a recipe for "Lemon Curd". The final paragraph says. "Process in a boiling water bath, then seal, label, and freeze for up to 4 months. Refrigerate once opened. Alternately, this recipe can be canned using a pressure canner."I did a Google and lemon curd and lemon butter seem to be the same thing, just a different name over here.
Yes these are definatly not as acid as a lemon. I tasted one yesterday and you can eat them like an orange, but they do still have a bit too much sour for me. I couldn't eat a wedge of regular lemon though. I think it's quite common here as I had heard of a lemonade tree before this http://www.daleysfruit.com.au/buy/lemonade-tree.htm
I also found lemon butter/curd its not really able to be bottled long term. That surprises me because you always see it for sale at school fetes but nobody ever puts a refrigerate and use within 2 weeks sticker on it.
I have "Honey Lemon Marmalade" "Lemon Ginger Marmalade", Lemon Lime Marmalade, and Apple Lemon Marmalade. A Bllueberry, Lemon & Lime Conserve too. Point? you might consider mixing them lemons with something else.
"Conserves differ from jams in that they contain large pieces of fruit or whole fruits, the fruits are steeped in sugar before cooking to firm them up, and they are boiled more gently than jam. Serve on toast or bread, muffins or scones".