EP0844195B1 - Closed container containing a pulverized substance - Google Patents

Abstract

The capsule is made from a material which is impermeable to oxygen and water vapour and is designed to hold roast and ground coffee of which 5-15% of the fine particles are at least 90 mu m in size. The capsule is made from two identical layers of a supple material, circular, oval, or polygonal in shape, or with a round or truncated conical dome (11). It can be made, for example, from aluminium, plastics or a multilayered material, incorporating an oxygen-proof barrier of EVOH or PVDC (vinylidene polychloride), or paper and polyethylene, metallised polyester. Composite materials can also include polypropylene and polyamide.

Description

The present invention relates to a closed enclosure, containing a powdery substance for preparation a drink, said substance being roasted and ground coffee, provided to be extracted under pressure, the material used to said enclosure is impermeable to oxygen and to vapor of water for the preservation of said pulverulent substance and said enclosure being opened under the effect of the sole pressure build-up during fluid injection extraction.

There are already many patents mentioning capsules or cartridges intended to be extracted under pressure. Mention may in particular be made of the patent application WO 94/01344 in the name of the plaintiff. In this request for patent, there is no mention of the particle size of roasted and ground coffee used: all grain sizes are possible. However, it may happen that for certain reasons, it is better to target more specifically a certain particle size.

The object of the present invention is to find an enclosure closed, intended for pressure extraction, in which increases the extraction speed, while ensuring a good extraction rate of the substance powdery used.

The invention relates to a closed enclosure according to the preamble of claim 1, wherein the roasted coffee and ground to a particle size as it includes between 5 and 10% of fines having a size of less than 90 microns respectively for a D (4.3) between 650 and 300 microns and it is compacted or packed.

There are several types of grind possible in the coffee field. The most widespread milling is done with mills with rollers with axial grooves, as per example a mill from the Company Probat. We get particles having a particle size distribution with a higher fines content (more than 10% of fines having a size of less than 90 microns for a D (4.3) included between 650 and 300 microns). We therefore plan to milling to obtain particles with a particle size distribution reducing the fines content. This is achieved by milling on mills with rollers with radial grooves, as per example a mill from the Matsubo Company. We get a Gaussian distribution in which we have a decrease in the fine content for D (4.3) such that mentioned above.

By D (4.3) we mean the average particle size based on their diameter according to the Rosin diagram Rammler.

The coffee used in the enclosure according to the invention is compacted or packed. Therefore, if we want to keep a fairly high extraction speed and good rate extraction, it becomes advantageous to work with a particle size distribution as mentioned in the claim 1. Packed means a compression under a pressure of the order of kg to a few tens of kg / cm2. By compacted is meant compression under a pressure of the order of a few hundred kg / cm2.

The determination of the particle size is done with a Malvern Mastersizer-S camera with a focal length of 4 to 3500 microns, which works with a laser beam: we put in butanolic suspension the particles we want determine the size, shake and pass a ray laser. We study the reflected beam and the data processing leads to distribution particle size statistics.

The closed enclosure according to the invention can be two types. The first solution is to consider a flexible capsule consisting of two flexible sheets identical in circular, oval or polygonal shape providing space for substance between them pulverulent and welded on their periphery so that that said bag is substantially symmetrical with respect to his welding plan. The second solution is to consider a cartridge including a cup with a bottom and side wall having substantially the shape of a trunk of cone or dome and a circular rim of diameter greater than the bottom and a seal welded to the around the rim of the capsule.

In the case of the second solution, the cup, of shape frustoconical and semi-rigid in nature, may be formed aluminum of the order of 20 to 100 microns, of pure plastic or multi-layer with possibly a oxygen barrier layer such as EVOH or PVDC, a multi-layer film such as cardboard, aluminum, plastic or cardboard, plastic with possibly a oxygen barrier layer such as EVOH or PVDC. The capsule seal, flexible in nature, can be made of aluminum of the order of 15 to 60 microns, or a multi-layer film comprising either paper from 20 to 60 g / m2, plastic such as PE from a thickness of the order of 20 to 60 microns and aluminum with a thickness of 5 to 20 microns, either EVOH or PVDC with a thickness of 5 to 30 microns and plastic (PP, PE, PA) of the order of 20 to 100 microns, i.e. PET (5 at 30 microns) and plastic (PP, PE) from 20 to 100 microns, either metallized PET or a high barrier layer such than SiO2.

couche extérieure : PET (normal,tissé, ou non tissé),PE, PP, PA, PS ou papier

couche centrale haute barrière : aluminium d'une épaisseur de l'ordre de 5 à 20 microns, EVOH, PVDC, PET ou PVA

couche intérieure : plastique, , de préférence PE ou PP ou OPP. On peut envisager les combinaisons multi-couches suivantes : PET-EVOH-PE ou PET-aluminium-PE.

In the case of the first solution, the sheets can be made of flexible material such as aluminum with a thickness of the order of 5 to 40 microns or plastic such as PET. Preferably, the sheets will be made of a flexible multi-layer material suitable for welding by the usual methods while constituting sufficient protection of the product against oxygen and water vapor. The following combination of materials is recommended:

outer layer: PET (normal, woven, or non-woven), PE, PP, PA, PS or paper

high barrier central layer: aluminum with a thickness of around 5 to 20 microns, EVOH, PVDC, PET or PVA

inner layer: plastic, preferably PE or PP or OPP. The following multi-layer combinations can be envisaged: PET-EVOH-PE or PET-aluminum-PE.

For the first and second solution, the coffee is packed or compacted. Preferably, for the first solution, the coffee is compacted and for the second solution it is Cup.

Fig. 1 est une représentation de la quantité de fines pour une certaine taille moyenne de particules D(4,3),

Fig. 2 est une représentation globale des tailles de particules avec un moulin Matsubo,

Fig. 3 est une représentation globale des tailles de particules avec un moulin Probat,

Fig. 4 est une représentation schématique de la capsule souple utilisable et

Fig. 5 est une représentation schématique de la cartouche utilisable.

The following description is made with reference to the drawings, on which

Fig. 1 is a representation of the quantity of fines for a certain average particle size D (4.3),

Fig. 2 is a global representation of particle sizes with a Matsubo mill,

Fig. 3 is a global representation of the particle sizes with a Probat mill,

Fig. 4 is a schematic representation of the flexible capsule that can be used and

Fig. 5 is a schematic representation of the usable cartridge.

The object of the present invention is to have a capsule or a ready-to-use cartridge, in which on a base with a capacity of 4 to 12 g of roasted and ground coffee, we manages to get a cup of coffee given less volume time with a Probat version while maintaining the same extraction rate.

To do this, the fines content must be limited. This result is achieved for enclosures containing fines according to curve C in FIG. 1. This particle size is obtained with a Matsubo mill. On the abscissa, we represent D (4.3), that is to say the average particle size in microns: each point corresponds to a grind. In ordinates, we represent the fine content, i.e. the content of particles having a dimension less than 90 microns. For comparison, we see on curve D the particle size distribution with a Probat mill: For identical values of D (4,3), we have a fine content higher.

Figure 2 shows on the one hand the distribution particle size from a logarithmic scale in abscissa: it is the Gaussian A, the ordinate on the left indicating the content in% for each particle size. We see well the maximum at 410 microns and the average size of particle D (4.3) is 383 microns.

Curve B sums the different particle sizes for go from 0 to 100%: ordinate on the right.

For comparison, Figure 3 shows the same particle size distribution, but with a Probat mill. The curve E indicates the Gaussian on the same scale as the previous figure, which clearly shows the content more high in fines. Curve F sums the different grain sizes and if we compare with curve B, we see although a higher content at 100 microns. In this case, on curve E, the maximum is at 409 microns and the D (4.3) at 380 microns.

Figure 4 shows a soft capsule containing coffee roasted and ground with the grain sizes according to the figures 1 (C) and 2 above. The bag (1) of circular shape has two sheets of flexible material (2) and (3) welded on their periphery (4) by heat sealing and containing ground roasted coffee (5) compacted for the preparation of a drink. The compacted coffee has convex faces (35), the general shape of its section being circular, thus than that of the bag. The cylindrical blank (38) of the wafer is intended to avoid the undesirable presence of grains in the welding area.

With regard to FIG. 5, the cartridge (11) has a cup (12) with a bottom (15) and a side wall of frustoconical shape (16). The cup is made of aluminum 50 microns thick. Cartridge contains coffee roasted (13) and it is closed by a cover (14) in aluminum / paper composite. This cover is welded to the edge (17) of the rim of the cup.

The following description is made with reference to examples.

Examples 1 to 3

The tests are carried out with a capsule according to FIG. 4 successively containing 4.6, 5 and 5.2 g of roasted coffee and ground having a D (4.3) of 355 microns.

We do an extraction on a machine according to the request of WO 94/02059. We prepare a 50 g cup of coffee. For the first capsule, we obtain the cup in 22 seconds with a Matsubo grind, while it takes 28 sec. to obtain the same quantity with a Probat grind. Yes we now look at the extraction rate, we see that they are identical.

For the 5 g capsule, with the grind according to the invention, a cup of 50 g is obtained in 21 sec. whereas with a Probat grind takes 24 seconds. Again, the rates are identical.

Finally, for the 5.2 g capsule, we obtain in 20 sec. a 50 g cup of coffee with ground coffee the invention, while it takes 26 sec. with coffee at Probat version. Extraction rates are still identical.

So we get to get with a speaker according the invention a faster extraction of coffee.

Abbreviations.

PVDC =

Polyvinylidene chloride

EVOH =

Copolymer of ethylene and vinyl alcohol

PP =

Polypropylene

PE =

Polyethylene

PET =

Polyester

PA =

Polyamide

PVA =

polyvinyl alcohol

OPP =

Oriented polypropylene

Claims (3)

1. Closed enclosure, containing a powder substance for preparation of a drink, the said substance being roasted ground coffee, which is designed to be extracted under pressure, the material used for the said enclosure is impermeable to oxygen and to water vapour, for preservation of the said powder substance, and the said enclosure being opened simply under the effect of the increase in pressure during injection of the extraction fluid, characterised in that the roasted ground coffee has a particular dimension such that it comprises between 5 and 10% fine product with a size of less than 90 microns, respectively for a D (4, 3) of between 650 and 300 microns, and it is compacted or compressed.
2. Closed enclosure according to claim 1, the said enclosure being a flexible capsule which consists of two identical flexible sheets with a circular, oval or polygonal shape, which have between one another a space for the powder substance, and are welded at their periphery, such that the said sachet is substantially symmetrical relative to its welding plane.
3. Closed enclosure according to claim 1, the said enclosure being a cartridge comprising a cup with a base and a lateral wall having substantially the shape of a truncated cone or a dome, and a circular edge with a diameter which is greater than that of the base, and a cap which is welded onto the periphery of the edge of the capsule.

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