Sealed capsule for the preparation of a beverage, in particular espresso coffee
A capsule ( 1 ) sealed without an internal filter. The capsule includes a cup-shaped body ( 2 ) with an outwardly projecting flange ( 2 a ), and a flexible lid ( 3 ) welded to the flange ( 2 a ) to define with the latter a sealed chamber ( 4 ) which is impermeable to oxygen and moisture and contains a quantity of granular material ( 5 ). The granular material ( 5 ) is first compressed inside the chamber ( 4 ) in a direction perpendicular to the plane containing the flange ( 2 a ), with a compressive load preferably of between 2 and 50 Kg per cm 2 of the average cross-sectional area of the chamber ( 4 ), so as to form a compact tablet ( 5 ) of the material. A vacuum is formed inside the chamber ( 4 ) to a degree such that the lid ( 3 ) adheres to the upper surface of the tablet ( 5 ).
1. A sealed capsule, for the preparation of a beverage, by means of pressurised extraction, comprising:
a cup-shaped body having a flange at the top projecting radially outwards; and
a flexible lid, welded to the flange of the cup-shaped body so as to define with the latter a sealed chamber which is impermeable to oxygen and moisture and contains a quantity of material in the form of granules for preparation of the beverage,
wherein the granular material is preliminarily compressed inside said chamber in a direction perpendicular to a plane containing the flange with a compressive load between 2 and 50 Kg per cm 2 of the average cross-sectional area of the chamber, so as to form a compact tablet of said material, and
wherein a vacuum is formed inside said chamber to a degree such that the lid adheres to the upper surface of said tablet.
2. The capsule according to claim 1 , wherein the cup-shaped body is substantially frustoconical and said chamber has a height roughly equal to half its average cross-sectional dimension.
3. The capsule according to claim 2 , wherein said chamber has a height (E) of between about 15 and 19 mm and the granular material contained therein is such that the granular material forms a compressed tablet having a height of between about 12 and 15 mm and between about 15 and 19 mm, respectively.
4. The capsule according to claim 3 , wherein said chamber has a height (E) of about 17 mm and the granular material contained therein is such that the granular material forms a compressed tablet having a height of between about 13 and 17 mm.
5. The capsule according to claim 1 , wherein during use, the capsule is perforated beforehand along the bottom wall of the cup-shaped body before injection of an extraction fluid through the lid, the bottom wall of the cup-shaped body having a thickness of between 150 and 400 μm.
6. The capsule according to claim 5 , wherein the bottom wall of the cup-shaped body has a thickness of between 150 and 220 μm.
7. The capsule according to claim 5 , wherein the capsule is adapted to receive, during use, an extraction fluid at a pressure of between 4 and 11 bar.
8. The capsule according to claim 1 , wherein the capsule contains ground roasted coffee, with a size of the coffee granules ranging between 180 and 400 μm.