Winter may bring cold winds, torrential rains, and a host of other reasons to feel down – but it also gives us a couple of reasons to celebrate its arrival. Namely: lemons, limes, kumquats, clementines, and – chief among them – blood oranges. These red citrus fruits are only available for a short period of time between December and May. Luckily we can keep enjoying the distinctly sweet flavour of these red oranges by making Blood Orange Marmalade. But first, let’s talk about blood oranges.
What does a blood orange taste like?
The answer to that is – it depends. Some types, like Moro, taste very different from normal oranges. They’re bitter, and less sweet with a berry-like flavor. Other types, like the Sicilian Blood Orange taste like a normal orange, but much sweeter. As a side-note, I prefer Sicilian Blood Oranges due to their sweetness for blood orange marmalade. They’re also grown closer to home, so I get to keep my carbon footprint low!
Why are blood oranges red?
Blood oranges are red due to the presence of anthocyanins which naturally occur in many fruits, but rarely in Citrus. Anthocyanins develop the deep red flavor in low temperatures – one of the reasons you rarely see blood oranges outside of the winter months. Some types of oranges will also give a deeper, redder color than others. Moro oranges are a dense maroon color, whereas Sanguinello oranges are often a deep orange with flecks of bright red in it. Now – let’s get to the good stuff.
How do you make marmalade?
Fruit preserves form into a gel – a mixture of water and other molecules which have bonded together to form a solid. These molecules form a sponge-like network which traps water into pockets. To create this network in marmalades we need a molecule called Pectin. Luckily, citrus fruits are full of Pectin. They’re hidden in the cell walls from where we can extract them.
The pith has a high concentration of Pectin, which is why we won’t be throwing this away. I repeat. Do not throw the pith or peel away. We need it and its sweet, sweet Pectin. The problem is that by coaxing them out of the fruit’s cell walls, pectin molecules float away from each other. To make matters worse, Pectin gets a negative electrical charge this way, and it will repel the other molecules. Hence, we’ll need to give Pectin the right environment to get reacquainted.
How to get Pectin to mingle:
- First, we’ll add a boatload of sugar. This sugar will attract water molecules for itself and away from Pectin, leaving Pectin more exposed to each other.
- Second, we’ll boil the fruit mixture to evaporate the water, forcing Pectin molecules to get closer to each other.
- Third, we’ll increase acidity which will in turn negate Pectin’s negative electric charge and allow it to get closer. And guess what the ideal PH for this is? Between 2.8 and 3.5. Roughly the acidity of a blood orange. Don’t you love it when things just work out? This is why many fruit preserves require an acidic fruit to be added to the mix, such as the lemon.
Now ideally, while you have your sugary, fruity mixture on the stove you would reach 105°C (221°F) which is when we know that sugar concentration is at 65% (yes, this is the concentration you want). Of course, we don’t have an inbuilt way of checking temperature to the exact degree, so I recommend you get yourself a candy thermometer.
Alright, so now you know all about blood oranges, how a marmalade is made, and you’re ready to get cooking. Right?
Not exactly. If you want your marmalade to last a while (i.e. 6 months) you will need to sterilize your jars. You need to have your jars ready when the marmalade is ready. You cannot begin jar sterilization after the marmalade is ready. By the time you’re done sterilizing, your marmalade may have already been compromised with heat-resistant bacteria.
- 5 large blood oranges (900 grams / 2 lbs)
- juice of 1 lemon
- 2tbsp of fresh mint, stems removed
- 100ml / 3.4oz campari
- 1.7L / 7 cups and 2oz water
- 2kg / 4.4lbs caster sugar (preserve or jam sugar works here)
- Cut the oranges into thin slices, making sure to remove all the seeds. Then cut the slices into quarters.
- Place the oranges into a large pot, add the lemon juice and water, and bring to a boil.
- Once the mixture is boiling, reduce to a simmer. Simmer for 45 minutes. You can use this time to sterilize your jars (try these methods), and pop a small plate into the freezer – you’ll need this to test the marmalade’s readiness later.
- Now you can add the sugar and mix it in. You need to keep this moving, treat it like a risotto. Put your sugar thermometer in there, and let it get to 105-106 degrees celsius (221-223 fahrenheit). Try not to let it go higher.
- Once the target temperature has been reached put the mint in a teabag or cheesecloth, and then into the marmalade with the campari. You want to avoid having pieces of mint in there, and instead let its flavor infuse.
- Stir for a couple of minutes, then grab a teaspoon of marmalade and put it on the chilled plate. Wait for half a minute and then begin to tilt the plate. If the mixture runs across the plate, it’s not set yet. Keep the jam between 105C and 106C (221-223 fahrenheit) then try again after a few minutes.
- Take the blood orange marmalade off the heat and leave for 15 minutes. Then pour it into the sterilized jars. Enjoy over the course of 6 months. And please, please, please do not put hot marmalade into a cold jar. This is a marmalade recipe, not a grenade recipe.