Filter-paper insert

1. A filter-paper insert for making brewed coffee, comprising:

at least two layers of filter paper having three sides, including a base and two opposite sides, the at least two layers of filter paper being connected together at a base and at the two opposite sides to define an interior space fillable from a filling opening opposite the base,

wherein the at least two layers of filter paper includes a lower region adjacent to the base and an upper region adjacent to the filling opening,

wherein the lower region and the upper region of the at least two layers of filter paper includes a plurality of slots to increase the permeability of coffee oil from the brewed coffee,

wherein one of the slots of the plurality of slots is formed on the crimped portion of the at least two layers of the filter paper,

wherein the crimped portion comprises sidewalls and a base section and is substantially pot-shaped,

wherein the slot is arranged on a base section of the crimped portion; and

wherein the lower region has fewer slots of the plurality of slots per surface area than the upper region.

2. A filter-paper insert according to claim 1 , wherein said plurality of slots in the upper region include a longer arrangement than in the lower region.

3. A filter-paper insert according to claim 1 , wherein said plurality of slots having a length, and wherein said plurality of slots are wave-shaped.

4. A filter-paper insert according to claim 1 , wherein said plurality of slots having a length, wherein the length of said plurality of slots is greater than 1.5 mm.

5. A filter-paper insert according to claim 3 , wherein the amplitude of said wave-shaped slots is at least 20% of said length of said wave-shaped slots.

6. A filter-paper insert according to claim 1 , wherein said plurality of slots having a length, wherein the length of said plurality of slots is less than 6 mm.

7. A filter-paper insert according to claim 1 , wherein said at least two layers of filter paper insert includes a middle region between the upper region and the lower region, wherein the middle region includes a plurality of slots, and wherein the middle region includes more slots than the lower region and fewer slots than the upper region.

8. A filter-paper insert according to claim 1 , wherein said plurality of slots having a length, wherein said plurality of slots are arranged in horizontal rows and a distance between said plurality of slots lies between about 5 mm and about 40 mm.

9. A filter-paper insert according to claim 8 , wherein the distance between said plurality of slots is smaller in the upper region than in the lower region by more than 20%.

10. A filter-paper insert according to claim 1 , wherein said plurality of slots in the lower region are shorter in length than in the upper region by more than 20%.

11. A filter-paper insert according to claim 1 , wherein at the lower and the upper regions are separated from each by a crimped portion.

12. A filter-paper insert according to claim 7 , wherein the lower, middle and upper regions are respectively enclosed by a crimped frame portion.

13. A filter-paper insert according to claim 1 , wherein said plurality of slots are S-shaped.

14. A filter-paper insert according to claim 1 , wherein the filter-paper insert is configured to allow filtered brewed coffee to contain a fraction of coffee oil greater than 0.025% after filtration of 50 g of coffee grounds and 1100 mL of hot water.

15. A filter-paper insert according to claim 1 , wherein said at least one crimped portion protrudes outwardly from at least two layers of the filter paper.