Method
Prep:35min  ›  Ready in:35min 

1. Combine potatoes and water in a small pot. Cover and boil until potatoes are tender, about 35 minutes. Drain cooking liquid into a large glass measuring jug. Reserve potatoes for another use.
2. Transfer 275ml (10 fl oz) of potato liquid to large ceramic or glass bowl. Add flour, sugar and salt to bowl; stir to combine. Cover bowl with muslin or cheesecloth and let stand at room temperature until starter begins to ferment and bubble, about 4 days. Starter is now ready to use as required in a sourdough bread recipe.

Storage and feeding of starter:

Transfer to covered plastic container and store in refrigerator. Feed starter every 2 weeks. Begin each feeding by discarding all but 225ml. Mix 125g flour and 225ml warm water (45 C) into remaining mixture. Cover with cling film; let stand at room temperature overnight. Replace lid; return to refrigerator.