Extracting a perfect cup of coffee requires consistent water temperature: Too hot and the coffee will taste acrid, but too cold and the coffee will be weak and sour. From Fellow, a San Francisco startup that's a favorite among coffee connoisseurs, the Stagg vacuum-insulated dripper keeps temperature constant and prevents heat loss. Plus, the interior has a steeper slope than most pour-overs, maximizing contact between water and coffee grounds. A detachable bottom piece doubles as a drip cup and measuring guide. Fellow offers the Stagg Dripper in two sizes: a traditional X model, or a taller XF version that you can fill up and leave to drip, combining pour-over and immersion brewing methods.