Traditional Irish Blackberry Jam

This traditional Irish blackberry jam is made using equal weights of blackberries and sugar, and nothing fancy beyond patience and a good pot.

The addition of one small shot of whiskey or poitín is not about alcohol, it’s about depth. Added at the very end, it lifts the flavour of the fruit without overpowering it.

This is a small batch recipe, producing six 250 ml jars, ideal for home use or gifting.

Recipe Overview

• Yield: Approximately 6 × 250 ml jars
• Total finished jam: About 1.5 litres
• Skill level: Beginner
• Storage life: Up to 12 months unopened

Ingredients

• 1.5 kg fresh blackberries
  (Wild blackberries give the best flavour)
• 1.5 kg sugar
  (Jam sugar or plain granulated)
• 1 shot (25–30 ml) whiskey or poitín
  (One shot total for the entire batch)
• Optional:
• Juice of ½–1 lemon
• Small knob of butter (to reduce foaming)

Equipment:

• Large, heavy-bottomed pot: Big enough to allow the jam to boil hard without overflowing. A wide pot helps the jam reduce properly.
• Sterilised jars with lids : 6x 250 ml jars
• Kitchen scales: Accurate weighing is important for the 1:1 fruit-to-sugar ratio.
• Wooden spoon or heatproof spatula: For stirring without damaging the pot or splashing hot jam.

Method

1. Prepare the fruit
   Gently wash the blackberries and remove any leaves or stems. Place the fruit into a large, heavy-bottomed pot.
2. Cook the blackberries
   Bring the fruit to a gentle simmer and cook for about 10 minutes, stirring occasionally, until the berries soften and release their juice
3. Add the sugar
   Add the sugar and keep the heat low, stirring continuously until the sugar is completely dissolved. Do not allow the mixture to boil at this stage.
4. Bring to a rolling boil
   Increase the heat and boil hard for 8–12 minutes, stirring occasionally to prevent sticking. Skim off any foam, or add a small knob of butter to reduce it.
5. Test for set
   Spoon a small amount onto a cold plate. After 30 seconds, push it with your finger — if it wrinkles, the jam is ready.
6. Add the spirit
   Remove the pot from the heat and stir in one single shot of whiskey or poitín. Add lemon juice now if using.
7. Jar and seal
   Pour into hot, sterilised jars, seal immediately, and allow to cool completely.