If you can’t purchase it directly from the roaster within a week or so of it being roasted, opt for a vacuum-sealed bag from a reputable national coffee-bean roaster. If possible, choose a burr grinder in place of a normal blade grinder. For best results, grind the coffee fresh right before brewing each day.  Experiment with different ground size. Although finer grounds are generally preferred, they can result in a bitterer brew than coarse grounds. Many people recommend that you aim for grounds the size of coarse sugar. If you like the water taste of the water that comes out of your tap, it’s likely to make good coffee. Softened or distilled water should never be used, but carbon-filtered water can reduce the chemical taste of some tap water. Minerals in water are important for the brewing process.

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Write a summary of the previous text in Chinese:
购买新鲜烘焙的咖啡豆。 购买咖啡研磨机，或者在店里磨好咖啡豆。 使用优质的水。