Bitter and sweet orange marmalade

Gargnano on Lake Garda has many bitter orange trees. Their fruit makes wonderful marmalade and a digestive liqueur; I have an old recipe from my grandmother to publish soon.
Here is my quick, simplified marmalade.
Ingredients
Equal weights bitter and sweet oranges. Sugar is half the resulting pulp weight:
1 kg bitter oranges
1 kg sweet oranges
Sugar: Gelierzucker 2:1 for the quick method, granulated sugar for the traditional version, half the resulting pulp weight
I remove the outer peel without white pith from 6 oranges, 3 of each type.

I cut very thin strips.

I put in cold water in a saucepan and bring to the boil.

I remove from heat and drain in a sieve.

I repeat 3 times and set aside.
With a small serrated knife, I completely peel the sweet oranges, removing the white pith too.

I cut between the membranes dividing the segments and collect them in a bowl.


After removing the segments, I squeeze the remains by hand to extract all the juice.

I repeat with the bitter oranges.

This is harder because they usually contain many pips. I press their pulp through a sieve with a spoon to remove them.

I weigh the zest strips and pulp from all the oranges.


I add sugar, half the pulp weight. I used German sugar containing pectin, which thickens without long boiling and preserves a lovely orange colour. It is readily available in supermarkets.
Alternatively, use equal weights pulp and sugar and boil to the desired consistency.

I put everything in a saucepan and boil.

I boil for 5 minutes. With ordinary sugar, allow much longer, at least 1 hour.

Before starting, I sterilise jars and lids covered with boiling water for 30 minutes.

I remove and dry upside down on a towel.

I fill with boiling-hot marmalade.

I close and turn the jars upside down for 5 minutes, then upright.

Cool until you hear the familiar click of the vacuum seal.