For most folks, a digital scale is the best thing you can own in your home to improve your coffee game.
Because many of us brew coffee at home while we’re still waking up or wrestling our kiddos for time at the toaster, we tend to be inconsistent with coffee brew ratios. Coffees vary in density and the instructions for brewing coffee often say to measure by the scoop per cup, but no two people can agree on what a “scoop” is or what a “cup” is. But fear not! You can lean on grams per liter as a universally consistent way of measuring how much coffee and water you’re using.
If you already have a scale, a good grinder is easily the next best thing you can spend your cash on. $20 blade grinders from the big box stores will smash your coffee into smaller particles, but it’ll be horribly inconsistent. A good burr grinder might give you a bit of sticker shock, but a $139 high-quality grinder will last you a lifetime and provide consistently delicious coffee every time, easily a worthwhile investment.