For better flavoured coffee, grinding should only be done when you're ready to drink your coffee. Ground coffee can last up to 10 days, but 10 day old coffee does not taste as nice as fresh coffee, and you don't want that last cup to be your last reminder of your roasted coffee.
Any coffee grinder will work effectively, however research shows that the best quality grind comes from a Ceramic Burr grinder. The reason is that you get a more consistent grind, and ceramic, being a natural substance, does not emit any flavours into your beans, and also will not rust over time. Electric grinders are great for home use, but in my personal opinion, don’t beat the fun, and price, of a good manual grinder. It’s perfect for a camping weekend too!
*The fine print: A course grind will produce weaker coffee unless more is used and it is brewed for longer. A fine grind will produce a stronger coffee and does not require to be brewed for long (and is more suited for coffee machines using pressure).
Before you start grinding, make sure the grind level is correct for the brewing method you intend to use.
Coffee Press: Medium to course
Manual Drip Brew: Medium
Coffee Percolator: Medium to fine
Espresso Machine: Fine to very fine
Italian: Very fine