Coffee filters come in a variety of different materials, ranging from simple paper filters that are for single use, to cloth or gold filters that can be washed and used repeatedly. For coffee making, coffee filters hold the ground coffee, keeping the grounds from getting into the coffee. The beverage is produced by pouring hot water through the coffee filter and grounds.
Not all coffee makers employ coffee filters. Percolating types of coffee makers and espresso machines have small metal cups into which the coffee is placed. These tend to do as a good a job keeping coffee grounds out as do filters because the holes in the cups that allow the coffee to circulate or run through are usually too small for coffee grounds to pass. French press coffee makers also don’t employ coffee filters, but instead push the coffee down to the bottom of the pot, so when you pour from a press, little to no grounds end up in your coffee.
Most coffee makers that use coffee filters are drip varieties. The simplest are hand drip coffee makers, which come in both individual cup sizes and also in large pots. Others are automatic drip machines, where again, the filter is placed in a conical or round receptacle, and then coffee is placed in it.
It's important to find the appropriate size coffee filters for your coffee machine. Usually the machine’s operating directions will tell exactly what kind is needed. The simplest filters are paper, made of either bleached white, or unbleached paper. These were once the most popular type of filter, but some are concerned about the continued use of paper and deforestation, which led to the development of both cloth and gold filters.
Cloth filters are a bit more challenging to find. Gold filters can be found in abundance and look like they are made of fine net. They may be sold with your coffee maker or you may have to buy one separately. One advantage of gold filters over paper is that you don’t need to keep spending money to buy paper filters. Upfront cost is more expensive, but over time these tend to save money.
There have been some concerns with gold filters and with coffee makers like the French press. They may not filter pesticides and chemicals in coffee, which are more effectively filtered by paper. You can avoid this somewhat by using organic coffee, or switching to paper filters. Yet, some coffee purists argue that paper filters tend to result in coffee with less flavor, and further, white paper filters can give off chemicals that are just as bad for you. Unbleached paper can help you avoid receiving an unhealthy dose of dioxin, which is present in bleached paper.
Another disadvantage of paper filters is that if you run out, you’ve got no way to make coffee. For veteran coffee drinkers, being confronted with no coffee filters in the morning can be a tragic experience. There is a little trick if you’re in desperate need of a filter and only have a used one. Carefully dump the coffee from the used paper filter, and carefully rinse the filter. As long as you do this gently, the filter will not be likely to rip, and you can reuse it. Multiple uses aren’t recommended, but you can normally get away with at least a second use of a paper filter in a “coffee emergency.”