Go Sour: Use your loaf

On a counter, on a wine farm, there's a large glass jar containing a thick liquid of a mushroomy, off-white shade. There are small bubbles in the slop. There are worrying indications of condensation on the inside of the jar. It's alive. But what is it?I ask the man behind the counter. He is one of the bakers at Lust, the newish bistro and bakery at Vrede en Lust.