Beverage capsule

1. A capsule for use in a high pressure espresso coffee machine, which machine has a capsule cage for retaining the capsule in an extraction position, wherein the capsule is formed from a ductile metal, the capsule having a generally frusto-conical form with an upper surface and a lower surface, an annular flange being provided at the lower surface, which annular flange is provided with a sealing means on a surface of the flange facing towards the upper surface of the capsule, wherein the sealing means comprises a ring formed from a cellulose material or paper, which ring is substantially flat and has a vertical cross-section with a rectangular shape, and which ring deforms plastically in use when engaged by the capsule cage of a coffee machine to provide a seal, the seal being held in position on the flange.

2. The capsule according to claim 1 , wherein the sealing means comprises a first layer of cellulose material and a second layer of adhesive material.

3. The capsule according to claim 2 , wherein the sealing means comprises a further layer of a bioplastic material.

4. The capsule according to claim 2 , wherein the sealing means comprises a further layer of aluminium foil and a further adhesive layer.

5. The capsule according to claim 1 , wherein the ring is formed of a cellulose material with a weight in the range of 100-400gnr 2 .

6. The capsule according to claim 1 , wherein the ring has a thickness of between 0.1 and 0.3 mm.

7. The capsule according to claim 1 , wherein the ring is approximately 0.25 mm thick.

8. The capsule according to claim 1 , wherein water in the capsule cage causes a small amount of swelling of the cellulose material or paper of the ring.

9. The capsule according to claim 1 , wherein the sealing means comprises a triplex laminate.

10. The capsule according to claim 9 , wherein the triplex laminate has an adhesive underside.

11. A capsule for use in a high pressure espresso coffee machine, which machine has a capsule cage for retaining the capsule in an extraction position;

wherein the capsule is formed from a ductile metal, the capsule having a generally frusto-conical form with an upper surface and a lower surface, an annular flange being provided at the lower surface, which annular flange is provided with a sealing means on a surface of the flange facing towards the upper surface of the capsule;

wherein the sealing means comprises a ring, which ring is substantially flat and has a vertical cross-section with a rectangular shape, and which ring deforms plastically in use when engaged by the capsule cage of a coffee machine to provide a seal, the seal being held in position on the flange; and

wherein the ring is a layered structure that includes (i) a first layer of cellulose material, (ii) a second layer of adhesive material, and (iii) a third layer of a bioplastic material.

12. A capsule for use in a high pressure espresso coffee machine, which machine has a capsule cage for retaining the capsule in an extraction position;

wherein the capsule is formed from a ductile metal, the capsule having a generally frusto-conical form with an upper surface and a lower surface, an annular flange being provided at the lower surface, which annular flange is provided with a sealing means on a surface of the flange facing towards the upper surface of the capsule;

wherein the sealing means comprises a ring, which ring is substantially flat and has a vertical cross-section with a rectangular shape, and which ring deforms plastically in use when engaged by the capsule cage of a coffee machine to provide a seal, the seal being held in position on the flange; and

wherein the ring is a layered structure that includes (i) a first layer of cellulose material, (ii) a second layer of adhesive material, (iii) a third layer of aluminium foil, and (iv) a fourth layer of adhesive material.