Starting from scratch

If you don't have access to somebody else's starter you'll need to create your own. Start with 75g of flour and 75g of water in a small sealable container like a jam jar. Don't seal the top, just place the lid on but don't screw it down, leave it at room temperature.

Every day for the next 5 to 7 days you'll want to discard half of it and feel it another 75g of flour and water. Once it's looking quite bubbly it's ready to go.

Feeding your sourdough

Once you've got it going, or if you're starting from somebody else's, you can reduce how much you're feeding it. Still discard half but just add around 20g of plain flour and water each day. You'll now want to start sealing the top.

If you're not using it or you're going away you can store it in the fridge, but you'll still need to feed it every 1 to 2 weeks. Make sure to take it out and feed it for a couple of days before you want to use it.