Hi, I’ve got three cask ale lines, and recently took delivery of a new brew from a new brewer. I had another kind of beer from him which was fine (very good actually!). This latest one has been pegged for 48hrs, and tapped for 24. It smells badly of sulphur, I can’t serve it. The line it’s on is brand new, all my lines are cleaned weekly. Is it a beer problem or a dispense problem?