Capsule, system and use of the system for preparing double beverages like a double espresso, a double lungo and a double ristretto

A system comprising an apparatus for brewing coffee and a set of capsules comprising a capsule of a first type configured to prepare a single espresso, single ristretto or single lungo and a capsule of a second type configured to prepare a double espresso, double ristretto or double lungo, wherein the single espresso and the double espresso, the single ristretto and the double ristretto, or the single lungo and the double lungo have a strength of 2.5-4% and a yield of 20-29%, each capsule comprising:

• a frusto-conical capsule body comprising:
• a circumferential side wall extending around a central axis of the frusto-conical capsule body;
• a bottom wall connected with a first end of the circumferential side wall for closing off the first end of the frusto-conical capsule body;
• a flange extending radially outwardly from a second end of the circumferential side wall;
• wherein the capsule further includes:
• a foil lid that is connected with the flange;
• a coffee bed of coffee grind that is accommodated within an internal space bounded by the frusto-conical capsule body and the foil lid, the coffee bed having a maximum coffee bed diameter that corresponds with an inner diameter of the frusto-conical capsule body at the second end of the circumferential side wall, the internal space having a height defined by the maximum distance between the bottom wall and a plane in which the second end of the circumferential side wall extends;
• wherein a top radius, bottom radius and height of the capsule of the second type are scaled relative to the capsule of the first type by a single scale factor;
• wherein the scale factor is in the range of 1.3-1.7;
• wherein the weight of the coffee bed in the capsule of the first type is in the range of 4-8 grams, and wherein the weight of the coffee bed in the capsule of the second type is in the range of 9-13 grams and wherein the (height)/(maximum width) ratio of the coffee bed in the capsule of the second type is within the range of 0.9-1.2;
• the apparatus comprising:
• a first brew chamber part and a second brew chamber part, closeable against each other to form a brew chamber;
• a fluid supply system;
• a piercing member;
• an extraction plate;
• and
• an outlet.