I made a couple fo batches of marmalade this weekend.
Had another "3 for 2" boxes of Seville oranges from Waitrose during the week, froze 1kg (so have 3 x 1kg in the freezer) and marmalised the rest in 2 batches, I prefer dealing with 1kg-worth of oranges at a time. I did add a ruby grapefruit to the second batch to made up the weight (with making sure that the freezer portion has at least 1kg in and with the oranges being quite large, the last batch was under on weight).
That's 3kg of oranges marmalised all together, I didn't add coriander to this lot like I did to the first lot, so see how different it is (if at all).
Should keep me going for a bit anyway.
I'm still not sure whether I prefer ruby/pink grapefruit marmalade vs Seville orange marmalade, the grapefruit marmalade is more bitter (and needs added pectin unless you find the unlikely thing of very pippy grapefruits) but both are nice. I guess the only answer is to eat more of both and see if I can decide
GC