I've managed to save my too-liquid-Meyer-lemon-marmalade. I put again everything in a big pan, added 1 ts of powdered agar-agar and then brought to a boil for 3'. And it worked! My "new" marmalade (photo on the left) is less jelly-like and more dense than the first one (photo on the right). But it tastes as good and, at least, it's spreadable! The idea of using the agar-agar powder comes from Clea's blog. In summertime, I made several times her strawberry jam. Very good.