Patent Application
20070261564
Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the method according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:
In greater detail,
The cup portion 2 comprises a base 7, a side wall 8 which protrudes from the base and a rim 9 which is arranged on the opposite side with respect to the base and forms an open end of the cup on which a corresponding rim 10 of the lid portion 3 is heat-sealed or otherwise fixed.
A plurality of ribs 20 are provided on the surface of the base 7 that is directed toward the internal volume of the cartridge 1 and are adapted to form a fine canalization between the lower filter 5a and an opening 21 formed in the center of the base. At this opening, which forms the outflow point of the beverage, the base 7 has an outlet port 6, which protrudes from the base toward the outside of the cartridge.
The lid 3 is provided with a base 12 and with a beverage inlet port 13, which protrudes toward the outside of the cartridge, the top of which is generally closed and can be opened by piercing.
A cartridge which is substantially identical to the one described up to now is also taught by international applications WO 2005/092160 and WO 2005/092162, the contents of which are considered here as an integral part of the present patent application. These prior applications also disclose the use of an elastic septum which is arranged at the outlet port 6 and which, by having a through slit or otherwise an orifice which is very narrow, is capable of keeping closed in an airtight manner the internal volume of the cartridge until the pressure inside the cartridge reaches a certain threshold value, beyond which the septum undergoes deformation and consequently opens the slit or orifice, allowing the passage of the beverage through said widened orifice or slit.
European patent application 05020525.1, the contents of which also are included herein by reference, describes such a septum 24 made of elastomeric or rubber-like material, which is provided with a corresponding through slit 26 and is fixed to the internal surface of the outlet port 6 by means of a rigid supporting ring 25. The supporting ring 25, on which the elastic septum 24 is fixed, is provided with a peripheral protrusion 28, which engages a corresponding recess 29 formed on the internal surface of the outlet port 6.
In order to ensure more effectively the fixing of the ring 25, the cartridge 1 also comprises an optional septum cover 23, which can be locked by snap action on the outer surface of the outlet port 6 and has an internal cylindrical wall 36 which is provided with openings 39 in order to provide additional support for the rigid ring 25 and allow the outflow of the beverage through an opening 38 which is spaced from the axis of symmetry of the cartridge 1.
The cartridge 1 can be installed in a machine for preparing espresso coffee by means of an extraction assembly, preferably of the type shown in
The extraction assembly, generally designated by the reference numeral 40, is preferably composed of a support 41, which can be coupled to a pressurized hot water duct 45 which belongs to the machine, a bell-shaped element 42 which is fixed to the support, and a filter basket holder 43 which can be fastened to the bell-shaped element 42 by means of a bayonet coupling.
The support 41 preferably consists of the lower part of a boiler.
The filter basket holder 43, provided with a handle which is not shown in the figure, is provided internally with a cylindrical shape, which substantially matches the shape of the lateral surface of the cartridge, and preferably has an annular groove 44 which is adapted to receive the flange 15 which protrudes from the peripheral region of the base of the cartridge 1.
The support 41 of the extraction assembly, which can be fixed to the espresso coffee extraction machine, is provided with an injection needle 46 and with a mushroom valve 47 in order to adjust the flow of hot water that arrives from the duct 45 toward the inside of the cartridge. 1.
Other extraction assemblies can be used as an alternative to the one described, for example the assemblies known from international applications WO 2005/092160 and WO 2005/092162.
Another extraction assembly which can be used comprises a filter basket holder provided with a septum or valve which are normally closed and arranged at the outflow point of the extracted beverage and are capable of opening, under pressure or on command, a very narrow passage (on the order of tenths of a mm) for the extracted beverage.
Using the reference numeral 40 to generally designate an extraction assembly which comprises such a septum or valve, provided either in the cartridge as shown in
Preferably, the boiler 52 is substantially cylindrical and is arranged adjacent and coaxially to the extraction chamber which accommodates the cartridge 1. An opening for the inflow of cold pressurized water is present on the lateral surface of the boiler. The chamber inside the boiler 52 comprises the duct 45 of
With reference to
This step can be preceded by a step for mechanical piercing of the cartridge arranged in the filter basket holder, depending on the type of cartridge used. The embodiment described here can be applied to the extraction of espresso coffee from a dose of ground coffee powder weighing approximately 6-7 g.
A preinfusion step 105 then follows, during which hot water at a temperature from 90 to 99° C., more particularly at 96° C., is injected from the duct 45. The hot water is injected at a reduced flow-rate for a preset time interval (for example approximately 1.1 seconds). In this step, the pressure of the water is such that the septum 24, or more generally the septum arranged in the extraction assembly at the exit point of the beverage, remains closed. In particular, in the preinfusion step 105 the pressure of the water injected into the coffee pod 4 is much lower than the steady-state pressure and is substantially on the order of 2 bars, preferably less than 4 bars.
Once the preinfusion time has elapsed (step 110), the injection of water is interrupted (step 115) in order to allow the imbibition or homogenization of the coffee pod arranged in the extraction assembly 40 with the water injected in the preceding step.
After a second preset time interval has elapsed, for example 2.5 seconds (step 120), hot water at 90-99° C., more particularly at 96° C., is injected again into the cartridge according to a pressure ramp which depends on the hydraulic resistance of the machine-cartridge system and on the flow-rate of the pump 51 (step 125).
When a high pressure value, preferably higher than 6 bars or even more preferably ranging from approximately 6 to 9 bars, is reached, the elastic septum 24, or more generally the septum arranged in the extraction assembly at the exit point of the beverage, opens (step 130), so as to allow the beverage to pass through an orifice which measures a few tenths of a mm or is in any case very small.
The partition opens autonomously thanks to its elasticity. However, in other embodiments of the invention the partition can be replaced by any valve means, even an actuated one, so long as it is adapted to force the flow of espresso coffee through a very narrow passage before it exits from the extraction assembly.
It has been found that by using a cartridge with an elastic septum 24 which is pre-perforated in a central point 26, such as the ones described in patent applications PCT WO 2005/092160 and WO 2005/092162 and in European patent application no. 05020525.1, the pressure drop at the septum when it is in the open state ranges from approximately 5 to 7 bars.
An extraction step 135 then begins during which the coffee pod 4 is crossed by a flow of pressurized hot water and the espresso coffee exits from the septum. During this step, the pressure at the cartridge inlet ranges preferably from 9 to 12 bars and the average flow-rate ranges from 0.7 to 1.3 grams per second, for an espresso coffee preparation program, and 2-3 grams per second for a weak coffee preparation program.
The crema exits from the very first moments of extraction.
Finally, after approximately twenty seconds, the pump is stopped and the electric valve is closed. Extraction thus ends (step 140).
As a whole, the coffee pod 4 is percolated with a volume of water which, depending on the preparation, can vary from 20 to 50 ml.
By using a cartridge provided with a septum, such as the cartridge of
In traditional machines, the pressure drop between the upper layer of the coffee tablet and the lower layer in fact goes from 10 bars to approximately 0 bars (atmospheric pressure), whereas in the method according to the invention the pressure drop goes from approximately 10 bars of the upper layer to approximately 6 bars of the lower layer.
Moreover, in the traditional method there is substantially no pressure drop at the filter on which the coffee pod rests, since the beverage passes through a surface which is provided with a large number of holes and does not cause significant resistance to the passage of the beverage. In the method according to the invention, instead, the extracted coffee is forced to pass under pressure through a very narrow passage, i.e., with high resistance, provided in an elastic septum. Accordingly, in a very short time interval the beverage is forced to pass from a high-pressure region arranged upstream of the septum (6-7 bars) to a region at atmospheric pressure downstream of the septum.
It has been found that by using the method according to the invention not only is it possible to obtain a creamy espresso coffee, but the resulting crema has a considerable persistence over time, even 120 minutes, without the liquid fraction of the beverage being visible on the surface.
Moreover, in the effervescence step that occurs after percolation, the separation between the liquid phase and the crema is slower than in traditional processes. By way of example,
Each of the test tubes consists of a glass cylinder with standardized dimensions (outside diameter 27.5 mm, inside diameter 23.5 mm, height 72.5 mm).
It is possible to obtain a verification of this property by analyzing the backscattering properties of the sample contained in the containers of
The results are shown in
In the instrument used for the measurement, the light source has a wavelength of 880 nm (near infrared). An optical sensor arranged at 45° with respect to the incident beam receives the backscattering light that arrives from the sample. The sample in the cell is kept at 30° C. by means of a thermostat, and scans are performed on each sample, starting 10 seconds after percolation, for a total of five minutes and 10 seconds of analysis.
The figure shows immediately that the two fronts have a different imprint, and in particular the espresso coffee according to the invention has a backscattering value which is much higher than zero along the entire height of the sample analysis cell. This points out that the separation between the liquid phase and the foam is delayed in the beverage according to the invention with respect to traditional espresso, which instead has a region of separation between the liquid phase and the foam phase already after the 10 seconds that elapse between the end of percolation and the first scan.
With the same instrument it is also possible to highlight a percentage drop of the crema at a fixed time (for example 2 minutes) which is greater for the traditional espresso preparation.
The following table lists the average backscattering values for the two types of beverage, measured on seven different samples by type.
Organoleptic tests have shown that the crema is also less bitter and astringent than the crema obtained with traditional espresso coffee machines used at the professional level, whereas acidity and sweetness remain substantially unchanged (
Despite this, the distinctive characteristic of the beverage obtained with the method according to the invention is the persistence of the crema. In particular, it has been found surprisingly that the crema of the espresso coffee that is obtained is characterized in that the distribution of the diameters of the bubbles is substantially uniform in a diameter interval ranging from approximately 20 to 150 microns.
In greater detail, with reference to
It has been found that while in espresso coffee obtained with the traditional method many of the bubbles have diameters ranging from 20 to approximately 50-60 microns (line with triangles), in espresso coffee obtained with the method according to the invention over 40% of the bubbles have a diameter of more than 60 microns (line with diamonds).
Observing the development of the size of the bubbles over time, it has been noted that the beverage obtained with the method according to the invention always has bubbles with larger diameters.
Moreover, it has been found that the standard deviation for diameters from 80 to 150 microns is very low, and for these diameters the frequency ranges from 5 to 10%, approximately 10 times higher than that observed in espresso coffee obtained with the traditional method.
In practice it has been found that the beverage and the method according to the invention fully achieve the intended aim and objects, since they allow to achieve a considerable persistence of the crema independently of the factors that notoriously compromise its characteristics.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.
The disclosures in Italian Patent Application No. MI2006A000945 from which this application claims priority are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2006A000945 | May 2006 | IT | national |
