One of the secrets of making really good coffee is the filter that you use in your coffee maker. The standard paper filters are abundant, and the ones that are most often used. Barring other choices, they are at least sufficient. You certainly should not ever make coffee in an automatic drip coffee maker or in a percolator without using a filter. If you do, there will be little coffee grounds floating in the pot of coffee.
If you are going to use the paper coffee filters in your coffee maker, you need to buy the ones that actually fit your coffee maker. Paper coffee filters do come in various sizes and are made for specific brands of coffee makers. The reason that it is important that the coffee filter is a perfect fit for the coffee maker is that a coffee filter that is either too large or too small for your coffee maker will allow coffee grounds to get into the coffee — not a good thing.
While paper coffee filters are the ones most often used, they are not the only choice in coffee filters. There are permanent filters for coffee makers that can be purchased. These permanent filters must be cleaned thoroughly after each and every use. Believe it or not, there is even a permanent coffee filter that is actually lined with gold!
The very best choice of all coffee filters, though, is the cloth variety. Yes, it does have to be cleaned after each use, but coffee made using paper filters has a slightly papery taste to it, and cloth filters add no taste at all to the coffee. Cloth coffee filters are available in the same sizes as paper coffee filters. They are more expensive initially, of course, but they last much longer. Cloth coffee filters are made from unbleached cotton, so they are environmentally friendly as well.