How do the wildly variable supermarket sourdoughs stand up to the scrutiny of someone who’s been baking their own for years? • Everything you need to make great sourdough – and the kit you can do without How do the wildly variable supermarket sourdoughs stand up to the scrutiny of someone who’s been baking their own for years? Everything you need to make great sourdough – and the kit you can do without The Guardian’s journalism is independent. We will earn a commission if you buy something