Step 1

For the sourdough starter, soak raisins in 1/2 cup (125ml) lukewarm water for 15 minutes. Strain liquid, discarding raisins.

Step 2

Combine 40g flour in a non-reactive bowl with 1/3 cup (80ml) liquid to form a paste. Cover with plastic wrap. Leave to ferment for 24 hours at room temperature.

Step 3

The next day, add another 40g flour and 55ml water to make a slightly thicker, smoother paste. Cover and ferment for a further 24 hours.

Step 4

By day 3, the paste may have separated. Whisk in another 75g flour and 115ml water to bring it back to a smooth texture. Cover and ferment for a further 24 hours.

Step 5

By day 4, the starter should smell of vinegar and have surface bubbles. Discard half, then whisk in 75g flour and 115ml water. Cover and ferment for 24 hours.

Step 6

On day 5, your starter should be quite lively, with active bubbles. Whisk in 155g flour and 225ml water. Cover loosely to allow fermenting gases to escape. Set aside to ferment for 4 hours or until very bubbly. Chill for 12 hours before using. Keep starter chilled from this point on.

Step 7

For Mike's lunchbox sourdough loaves, make sure you make the sourdough sponge a day before baking. Combine starter with 300g flour and 300ml water until smooth. Seal in a sterilised 1L glass jar and stand at room temperature (25°C or below) for 2 hours or until it starts to bubble and increase in volume. Chill for at least 12 hours. Bring sourdough sponge to room temperature, then place in an electric mixer fitted with a dough hook. Add 3 cups (750ml) water. Mix on low speed for 2 minutes, then add remaining 1kg flour and mix for a further 5 minutes. Rest for 45 minutes.

Step 8

Add salt and mix on high speed for 5 minutes or until glossy and coming away from side of bowl. Use the ‘window pane test’ to test your dough: stretch the dough and, if it doesn’t tear, the gluten has been worked long enough. Transfer to a large clean bowl, cover and set aside at room temperature for 3-4 hours until increased in size by 11/2 and there are bubbles on dough when you pull it away from bowl.

Step 9

Transfer dough to a floured bench and cut in half. Shape each half into a loose ball by cupping floured hands around dough and pulling it towards you, then stretching it into a round shape against the bench. Rest for 30 minutes to rise slightly, then neaten with cupped hands and slip each piece into a greased 1.5kg (2.25L) loaf pan. Cover and chill overnight.

Step 10

Bring dough to room temperature. Preheat oven to its hottest setting. Place a roasting pan filled with hot water on the bottom shelf. Brush tops of loaves with water to allow loaves to rise fully before forming a crust. For lunchbox loaves, place a weighted tray on top of each pan or leave uncovered to form high-top loaves. Bake on middle shelf for 10 minutes. Reduce oven to 210°C and bake for a further 20 minutes or until bread sounds hollow when tapped and the crust is golden. Transfer pans to a wire rack to cool slightly, then remove loaves from pans and cool completely