What's your recipe? I tried making marmalade a couple of times and I found it was too thick and bitter. I suspect that there was too much orange peel vs juice and sugar. But I haven't really found a good explanation yet for what happened. Do you make yours by measuring or weighing the ingredients or do you just use x amount of oranges?
I'll try to do a write-up, but was mostly flying by the seat of my pants...
5 large (about the size of my hand) pieces of ginger
2 lemons
1/2 navel orange
2.5 cups sugar
1 packet gelatin
Cloves, star anise, turmeric
Cut ginger into slices and simmer for 30 minutes. Drain, but save the cooking water as ginger tea, with a bit of sugar added. The last 10 minutes, I added some cloves and star anise to the simmering pot, but the flavour wasn't really noticeable in the final product, so may want to try adding them sooner. Then puree the boiled ginger in a blender - could probably skip this step if chopped small enough, but I don't really like chewy pieces in my jam
Cut 1/4" off the ends of the lemons, then quarter them, and slice as thinly as possible, removing seeds as you go (I used the lemons whole, pith and all, surprisingly it wasn't too bitter at all).
Peel 1/2 orange with a peeler and cut the peel into small pieces. Remove the pith, quarter and slice the orange thinly (I didn't use the pith this time because it is so much thicker)
Simmer the lemons, orange, ginger, sugar and a pinch of turmeric for 45 minutes. I started with 2 cups of sugar and 30 minutes cooking time, but it just wasn't thickening up, so I added another 1/2 cup of sugar, gelatin, and cooked for another 15 mins and it turned out nice and thick.