One of the main drawbacks to using any single serve coffee machine that takes pods, is that you are limited to whatever types of coffee or tea that the manufacturer produces. Depending on the type of machine you use, that may or may not be a problem as many do have a large selection of pods to choose from.
There are now several options for re-fillable coffee pods where you can use your own coffee grounds. Not only does this offer an unlimited choice for coffee or tea, it also means less waste because you're not throwing away an empty plastic pod each time.
Not all makes of machines will allow for this, but there are a few choices particularly with the Keurig coffee maker.
For the Keurig Coffee Maker
Keurig was the first single-serve coffee maker to come up with their own refillable pod design. It's called "My K-Cup", and allows you to use whatever coffee grounds you want. It comes with a lid and reusable mesh filter cup. Because you are reusing the same cup over and over, you do lose the benefit of not having to deal with wet coffee grounds. My K-cups need to be cleaned out after each use, though they are usually dishwasher safe.
Not all models of the Keurig brew will work with My K-cups so you need to double-check the model numbers before buying. There are also other makes of fillable cups for the Keurig, such as the Solofill and the EZ-Cup. The EZ-Cup has a disposable paper filter inside so there is less cleaning to do.
For the Senseo Coffee Maker
Of course, since the Senseo takes the generic style of pods, these options are suitable for several different machines (One:One, Home Cafe, My Inventa etc). These are the gauze-type of flat pods. The best option to refill these is the Perfect Pod, which is a small device that uses compatible filter papers to make your own pods with any coffee grounds you want. As they are disposable, they are not really "refillable" and are disposed of after each use just like original pods.
The little Perfect Pod gadget holds an empty filter, and then seals it shut once you've filled it with your coffee grounds. The machine heats up to permanently seal the pod closed for great brewing and no leaks. You will need to buy more filter papers as you use them since they are disposable. For a non-disposable option, try the Ecopad. They are small plastic versions that are reusable though you will have to clean the ground out each time.
For the Tassimo Coffee Maker
Since the Tassimo relies on the bar code printed on the top of their T-discs in order to control the brewing, there is currently no options for making your own pods. But perhaps if the successes of the previously mentioned "do it yourself" options are any indication, maybe the Tassimo will have their own fillable pod in the future.
