Ingredients

9g yeast
125g water at 28 degrees
1 tbsp fennel seeds
1 tbsp caraway seeds
500g buttermilk
35g glycerine (optional)
100g black treacle
10g sea salt
250g rye flour
500g strong brown flour

Step 1 Mix the yeast
Dissolve the yeast in the water, stir in the sugar. Leave for 10 minutes.
Step 2 Toast the seeds
Toast the caraway and fennel seeds lightly for 2 minutes and then set to one side.
Step 3 Warm the buttermilk
Warm the buttermilk, glycerine, and treacle to 33°C.
Step 4 Mix the liquids
Stir in the warmed buttermilk mix, spices, salt.
Step 5 Add the flour
Stir in the rye flour stir well then add the strong white flour, stir well. Leave for 10 minutes.
Step 6 Knead
Turn out onto a lightly floured table, knead for 5 minutes then shape into a ball.
Step 7 Prove
Place the dough seam side up into a banneton then leave to prove until almost doubled. (This can vary, but as a guide it will take about 1 ½ hours depending on the temperature of your kitchen).
Just before the dough has doubled in volume, preheat your oven to 220°C. Put the dough into the oven over a tray and turn the temperature down to 200°C(Gas mark 6). Bake for 1 hour. Test by inserting a skewer, if it comes out clean then the bread is done.