As I’ve gotten older, I’ve noticed that my peers are less interested in the cheapest wine that still tastes good, and more enthusiastic about fancy home-brewed coffee made on increasingly impressive coffee machines.However, our collective dirty secret is that we aren’t actually sure that we’re making it correctly. Yes, we might be more mature now, but making coffee from bean to cup at home can often feel like we’re little children still playing house.To remedy this, and make sure that we’re all a little more enlightened, HuffPost UK spoke with Russell Jenkins, the Managing Director of Thomsons Coffee, to find out what the most common mistake is when it comes to making coffee.Jenkins says: “One of the most common mistakes people make when brewing coffee at home is using the wrong grind size for their brewing method. A grind that’s too fine can lead to over-extraction, resulting in a bitter and unpleasant cup.”I certainly can confess that I’ve made one (or 10) bitter and unpleasant cups of coffee.He adds: “Conversely, a grind that’s too coarse can cause under-extraction, leaving the coffee weak and sour.“Matching the grind size to your brewing method - whether it’s