The supermarkets sell pre-ground coffee, supposedly ‘suitable for all coffee makers’. It’s not. As previous;y reported, I couldn’t make drinkable coffee with the stuff in the expresso machine or the cafetier. LM gave up on my experiments, demanding I make her a mug of instant. I don’t blame her. My experimental brews tasted ‘orrible. Finally I worked it out. All this ‘brew for 4 minutes’ advice I was reading everywhere is for freshly and coarsely ground beans. I tried 3 minutes, then 2 minutes, the 1 minute. It was still horribly bitter. At 40 I hit the sweet spot. Coffee that tastes like, well, coffee. I bet it won’t work with the opened pack of ‘best before end 2008’ Columbian Blend I found at the back of the cupboard today.