This is roughly per kg of fresh or frozen wild blackerries. Scale up accordingly.

Makes around 400-500ml jam, plus 350-400ml of cordial.

Note: The cordial is about four times more concentrated that store brought regular cordial drinks, so dilute accordingly when it comes to drinking it. A little goes a realy long way!

Ingredients:

• 1kg wild blackberries, washed and discard any damaged
• ~800g caster sugar
• 1 Tbsp fresh lemon juice

Instructions:

1. Add the blackberries, lemon juice and sugar to a large saucepan, mix well.
2. Cover and leave the fruit at room temperature overnight.
3. The following day you’ll see that most of the sugar has dissolved, and a lot of juice has “sweated” out from the blackberries.
4. Place the saucepan on low heat for 3 minutes to gently warm up the blackberries without boiling (longer with more volume). Stir often until the sugar has dissolved entirely and has developed a nice deep blackberry flavour to the juice. 
5. Switch off the heat and carefully pour out 80% of the juice and set aside for cordial. It should be around 350-400ml.
6. Pour the blackberry juice through a sieve, pressing with the back of your spoon to get out as much of the juice as possible.
7. Then funnel your cordial into a sterilised bottle and seal.
8. The amount of juice remaining in the pan should be just enough to cover all the blackberries. Place the saucepan back on the stove on a medium-low heat until it starts bubbling. Simmer for 15-20 minutes, stirring occasionally until about half of the water has evaporated and the mixture starts to thicken (it will also thicken more as it cools).You can test a small bit of mixture on a clean surface and let it cool to see if it turns jammy.
9. Turn off the heat and let the jam rest for 15 minutes. Once the jam has cooled down, draw a line across the bottom of the pan with a spatula. If the jam is ready it will not flood back to fill the gap; if it’s too runny, boil for another 3-5 minutes and then test again.
10. Skim any scum off of the surface, stir well, pour the jam into sterilised jars and seal.
11. Place the jam jar in hot water and boil for 10 minutes to kill all the bacteria and to properly seal the jar. The jam can keep for at least six months in a cool, dark place.
12. Refrigerate jars once opened.