HK1055228A - Method and apparatus for preparing hot beverages - Google Patents

Description

Method and device for preparing hot beverages

Technical Field

The present invention relates to a method for preparing a hot beverage by brewing water extractable particulate matter, and to a device for preparing a hot beverage by brewing water extractable particulate matter.

Background

A large number of different kinds of methods for preparing hot beverages by brewing water extractable particulate matter are well known in the art. As a typical example, reference may be made to a so-called espresso coffee machine, in which ground coffee powder is filled into an infusion chamber. The coffee powder is compacted in the infusion chamber, after which hot infusion water is made to flow under pressure through the compacted coffee powder and extract it, thus preparing the coffee beverage.

In conventional espresso coffee machines, the temperature of the hot water flowing under pressure through the coffee powder contained in the infusion chamber is between about 85 ℃ and 98 ℃. In other words, in all known espresso coffee machines available on the market today, the temperature of the hot brew water flowing through the coffee powder contained in the brewing chamber is lower than 100 ℃. The reason for this is that all experts believe that if the temperature of the infusion water flowing under pressure through the coffee powder contained in the infusion chamber exceeds 100 ℃, the taste of the final coffee beverage is affected, since in this case bitter components are said to be extracted from the coffee powder.

Document EP0592943 discloses an espresso coffee machine for domestic use comprising a container for containing fresh water, a heating assembly located below the fresh water container, an infusion chamber for containing ground coffee powder, and a pump for delivering hot water from this container to the infusion chamber. The water contained in this container is heated to a temperature between 93 ℃ and 97 ℃. Hot water is delivered from the container by a pump into the infusion chamber where it is pressed against the coffee powder at the desired temperature between 93 and 97 c. Finally, the final hot coffee beverage flows from the infusion chamber into the receiving receptacle.

Us patent No.4287817 discloses a conventional coffee machine having a sieve or similar brewing device for making a substantially pressureless brew of coffee powder. The coffee maker is provided with a boiler comprising a hot water conduit connected to the bottom of the boiler and a steam conduit connected to the top of the boiler, the latter having a single steam outlet. This coffee maker is peculiar in that the boiler can produce hot water and steam. It is mentioned in the introductory part of the above-mentioned us patent that coffee machines are known in the art in which coffee powder is brought into contact with steam or brewing water that has been heated above the normal boiling point. However, the above-mentioned us patent does not give any specific suggestion as to the temperature of the infusion water during its passage through the coffee powder.

Document EP0812559 discloses a coffee machine in which a pressure piston is located above the actual infusion chamber; the pressure piston may be adapted to exert a specific pressure on the brewing water used for brewing the coffee powder. Between the infusion chamber and the pressure piston there is a control valve for performing the infusion operation steps, in which in the first step the coffee powder is moistened and in the second and third steps the extraction of the coffee powder is carried out. Even if it is noted that the brewing water can be raised to a higher temperature, it is not recommended to raise the temperature of the brewing water above the normal boiling point. Figure 2 of this document shows a brewing device designed according to the prior art in the field. The brewing device comprises a first water heater and a second water heater, the latter having a smaller volume than the former. This additional second water heater is designed to heat a smaller amount of water to a temperature of 180 c. The related introduction explains that, in a first step, this small amount of water heated to a temperature of 180 ℃ is used to moisten the coffee powder contained in the infusion chamber with a mixture of water and steam. However, this document does not give any further suggestion as to the actual brewing operation.

Finally, the document EP0934719 discloses a conventional coffee machine with a manually insertable filter holder. The basic idea of this invention is that in a first pre-infusion phase, an overpressure of water heated to a temperature of 120 ℃ is used to cause a small quantity of infusion water to flow into the coffee powder and wet it. After a time of 2 to 8 seconds the valve is opened, as a result of which fresh water pumped by the pump flows through the boiler in which the heating takes place, into the coffee powder contained in the filter holder, extracting it, and thus preparing the coffee beverage. No details or suggestions are given in the above-mentioned us patent as to the temperature of the brew water flowing through the coffee powder contained in the filter holder.

It can thus be summarised that in all the coffee machines disclosed in the above-mentioned documents discussed herein, the temperature of the brew water flowing through the coffee powder is lower than the normal boiling point of water.

Disclosure of Invention

It is therefore an object of the present invention to provide a method and apparatus for preparing a hot beverage by brewing water extractable particulate matter, wherein the particulate matter can be extracted more efficiently.

To achieve this and other objects, the present invention provides, according to a first aspect, a method of preparing a hot beverage by brewing a water-extractable particulate substance. The method comprises the following steps: filling particulate material into the infusion chamber; heating fresh brew water above the normal boiling point of water while maintaining the brew water in a fluid state; flowing heated water under pressure through particulate matter contained within the brew chamber at a temperature and fluid state above the normal boiling point of water, thereby extracting the particulate matter to produce a hot beverage; and collecting the hot beverage thus prepared and cooling it to a temperature below the normal boiling point of water.

According to a second aspect, the invention also provides an apparatus for preparing a hot beverage by brewing water-extractable particulate material. The device comprises: a supply of fresh brewing water, a feed water pump, a water heater adapted to heat the brewing water to a temperature above the normal boiling point of water, a brewing chamber adapted to contain particulate material extractable with the brewing water, a beverage outlet in communication with the brewing chamber, and a heat exchanger operatively interposed between the brewing chamber and the beverage outlet and adapted to cool a hot beverage brewed in the brewing chamber to a temperature below the normal boiling point of water.

Surprisingly, it has been found that when the beverage powder contained in the brewing chamber is brewed with brewing water that has been heated to a temperature above the normal boiling point of water, but is still in a fluid state, the taste of the brewed beverage is not affected at all. Subsequent cooling is necessary to prevent scalding of the person drinking the beverage and to ensure that the beverage flows out of the machine in liquid form, rather than in vapour form. It will be appreciated that the extraction of the beverage powder is very effective if the temperature of the water flowing through the beverage powder is above the normal boiling point of water.

Even though some of the above-mentioned prior art documents notice that the coffee powder contained in the infusion chamber can be wetted by steam or water heated to a temperature exceeding 100 ℃, none of the coffee machines disclosed in these documents comprises means and measures for brewing and extracting water which allow the coffee powder contained in the infusion chamber to be heated above the normal boiling point of water, but still in a fluid state. For this purpose, a pop-off valve or safety valve and a heat exchanger have to be arranged downstream of the infusion chamber. If this is not done, no liquid beverage can flow out of the beverage outlet, but only vapour.

Drawings

An embodiment of the device according to the invention will be further described in the following with reference to the accompanying drawing, in which a schematic view of the device for preparing hot beverages is shown.

Detailed Description

As mentioned above, figure 1 shows a device for preparing a hot beverage by brewing a particulate substance extractable with water. The apparatus comprises a tank 1 of fresh water, a feed pump 2, a heat exchanger 3, a brew chamber 4, a water heater 5, a steam conduit 7 with a steam valve 6 and a steam outlet 8, a beverage conduit 10 with a check valve 9 and a beverage outlet 11, and a brew water conduit 17 and a brew water valve 14.

The mode of operation of this device is as follows, assuming that the vapour valve 6 is closed and the brew water valve 14 is open:

fresh water is supplied by a feed pump 2 from a fresh water tank 1 via a cold water line 18 to a heat exchanger 3 and from there via a line 16 to a water heater 5, where the water is heated to a temperature above the normal boiling point of the water. The term "normal boiling point" is the boiling point of pure water under normal conditions, i.e. atmospheric pressure of 1013hPa at sea level. The water is preferably heated in the water heater 5 to a temperature between 110 c and 130 c. The check valve 9, which at the same time acts as a safety valve, ensures that the brewing water always remains in its fluid state, even when the water is heated to a temperature above the normal boiling point of water.

The hot brewing water flows from the water heater 5 through the brewing water conduit 17 to the brewing chamber 4 where it flows through the substance 13 contained therein, causing the active ingredient in such substance 13 to be extracted. The brewed beverage then flows through the heat exchanger 3 through the conduit 19, in which the beverage is cooled by fresh water; thus, the beverage is cooled to a temperature below the normal boiling point of water. Finally, the beverage flows from the heat exchanger 3 through the non-return valve 9 and the beverage conduit 10 to the beverage outlet 11, where the beverage is collected in the cup 20.

As can be seen from the figure, the heat exchanger 3 is connected to the water heater 5 through a heat exchanging element 15. These heat exchange elements 15 serve to preheat the heat exchanger 3 to a certain temperature. Thus, heat losses due to a number of components, such as the ducts 10, 17, the brewing chamber 4, the non-return valve 9, etc., being heated during the preparation of the first hot beverage can be compensated. If multiple cups of beverage are prepared consecutively, the heat loss is much lower, as the above components have already been heated. The thermal coupling between the heat exchanger 3 and the water heater 5 takes these circumstances into account.

The steam pipe 7 is connected to the outlet of the water heater 5 by a T-shaped flange 12. To generate steam, the brew water valve 14 located in the brew water line 17 is closed and the steam valve 6 located in the steam line is opened so that water heated to a temperature above the normal boiling point of water can flow out of the steam outlet 8 through the steam line 7. Since no check valve or safety valve is provided in the conduit 7, water in the vapour conduit, which is heated to a temperature above the normal boiling point of water, is in the vapour state and escapes as vapour. By this vapour, it is possible, for example, to heat the liquid contained in the cup 21.

Since the substance contained in the infusion chamber is infused by water heated to a temperature above the normal boiling point of water, but still in the fluid state, the extraction of the active ingredient of the substance contained in the infusion chamber is considerably improved without the drawbacks common today, such as the extraction of bitter ingredients from coffee powder. Since the water is always heated in the water heater to a temperature above the normal boiling point of water, the device can always provide steam if required.

This device for preparing hot beverages is particularly suitable for preparing espresso coffee. However, it will be appreciated that it may also be used to prepare other hot beverages, such as hot tea, hot chocolate drinks, hot soups and the like.

Claims (14)

1. A method for preparing a hot beverage, in particular espresso coffee, by brewing water extractable particulate matter, wherein the brewing water flows through a brewing chamber filled with said particulate matter in order to extract said particulate matter, characterized in that said brewing water is heated to a temperature above the normal boiling point of water while said water is maintained in a fluid state, so that said heated water flows under pressure through said particulate matter contained in said brewing chamber at a temperature and in a fluid state higher than the normal boiling point of water, so as to extract said particulate matter in order to form a hot beverage, said beverage being collected and cooled to a temperature below the normal boiling point of water before the prepared hot beverage flows out of a beverage outlet.

2. Method according to claim 1, wherein the brew water to be supplied to the brewing chamber is heated to a temperature above 100 ℃ and the brewed beverage is cooled to a temperature below 100 ℃.

3. The method of claim 1 wherein said step of heating water to a temperature above the normal boiling point of water and maintaining said water in a fluid state comprises the step of maintaining said heated water at an overpressure.

4. The method according to claim 1, wherein the brew water to be provided to the brewing chamber is heated to a temperature between 110 ℃ and 130 ℃.

5. Method according to claim 1, characterized in that the hot beverage prepared is cooled by means of a heat exchanger to a temperature below 100 ℃.

6. The method of claim 1 or 5, wherein the heat exchanger is cooled by the fresh brew water by introducing the water into the heat exchanger before the fresh brew water is heated to a temperature above the normal boiling point of water.

7. An apparatus for preparing a hot beverage by brewing water extractable particulate matter, comprising: a supply of fresh brewed water, a feed water pump, a water heater, a brewing chamber and a beverage outlet, characterized in that said water heater is adapted to heat said brewed water to a temperature above the normal boiling point of water, between said brewing chamber and said beverage outlet a heat exchanger is operatively interposed adapted to cool said hot beverage brewed in said brewing chamber to a temperature below the normal boiling point of water.

8. The device according to claim 7, further comprising means for increasing the pressure of the brewing water, said pressure increasing means being operatively interposed between the water heater and the beverage outlet and being adapted to keep the brewing water heated to a temperature above the normal boiling point of water in a fluid state.

9. The apparatus of claim 8, wherein the heat exchanger comprises a cold water conduit having an inlet operatively connected to the supply of fresh brew water and a hot water conduit having an outlet operatively connected to the water heater.

10. The device of claim 9, wherein an inlet of the hot water conduit is operatively connected to the brew chamber and an outlet of the hot water conduit is operatively connected to the beverage outlet device.

11. The apparatus of claim 7, further comprising a vapor conduit operatively connected to a conduit interconnecting the water heater and the brew chamber by a valve arrangement.

12. The device of claim 7, further comprising a valve device operably inserted into a conduit supplying the hot brewing water into the brewing chamber.

13. The apparatus of claim 7 further comprising a safety valve operatively inserted into a conduit supplying said hot beverage to said beverage outlet, said safety valve being adapted to maintain said brew water heated to a temperature above the normal boiling point of water in a fluid state.

14. The apparatus of claim 7, wherein the water heater and the heat exchanger are thermally coupled.