Susie and AJ admit they doesn't really know anything about fermentation and yet it underpins so much of the foodie stuff they love - sourdough, vinegar, beer, pickles etc etc. What is the mother thing? How do you get a starter? All is revealed with our two experts from Peter's Yard and Slow Vinegar. We never thought you could find a vinegar that genuinely tastes better than some wine, and the cheese and crackers are to die for!