I have made my annual trip to Stonemanor, the British supermarket near
Brussels, to buy Seville oranges for Marmalade.
This year I am folllowing Alan J. Flavell's recipe (used to be on the
University of Glasgow site; where is it/Alan now?).
This link is the recipe but not the original copy:
http://www.geocities.com/NapaValley/...html#marmalade

My question is: why, unlike jam, do you add so much water to the
orange juice/peel to make marmalade?

Alan's recipe uses 3 liters water for 1 kg of oranges.
Delia Smith uses 5 liters : 1.35 kg.

I got just over 300 mls juice from 800 grams of oranges; I plan to add
about 2.2 liters of water.

Doesn't this dilute the flavour? I would never do this with raspberry
jam !