CROSS-REFERENCE TO RELATED APPLICATION

This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2018/075110, filed on Sep. 18, 2018, which claims the benefit of European Application No. 17193105.8 filed on Sep. 26, 2017. These applications are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to an apparatus and method for preparing a coffee beverage.

BACKGROUND OF THE INVENTION

Automated coffee machines are becoming increasingly popular owing to their capability to dispense a cup of coffee at the touch of a button. Such machines tend to operate by passing heated water through a bed of ground coffee beans in order to brew the coffee.

During brewing, a number of different compounds are extracted from the coffee beans in order to give the brewed coffee its characteristic taste and color. During the extraction process caffeine may be extracted from the coffee beans, thereby providing the consumer with the well-known stimulant effect associated with brewed coffee.

Coffee beans are known also to contain the diterpene compounds kahweol and cafestol. It has been suggested that these diterpene compounds may act as agonist ligands for certain nuclear receptors, including the farnesoid X receptor and the pregnane X receptor. These diterpenes may thus block cholesterol homeostasis and therefore cause raised cholesterol levels (Ricketts et al.Mol. Endocrinol. vol. 21, issue 7, 2007, 1603-1616).

Non-filter coffee in particular may contain relatively higher levels of kahweol and cafestol which have been associated with increased low density lipoprotein cholesterol levels.

Brewing coffee having the desired taste characteristics but in such a way as to limit the extraction of these diterpene compounds is thus an important goal. It would also be particularly desirable to prepare a coffee beverage with a lower diterpene content in an automated manner.

WO 2016/160979 A1 discloses a pour-over coffee brewer apparatus.

DE 20 2005 020774 U1 discloses a coffee machine, in particular a fully automatic espresso machine.

DE 10 2009 032677 A1 discloses a coffee machine for preparing coffee and espresso.

DE 10 2015 109921 A1 discloses a method for producing a coffee beverage.

SUMMARY OF THE INVENTION

The present invention seeks to provide an apparatus and method for preparing a coffee beverage portion in such a way as to maintain taste characteristics whilst limiting the extraction of diterpene compounds such as kahweol and cafestol.

The invention is defined by the claims.

According to an aspect of the present invention there is provided an apparatus for preparing a coffee beverage portion from a volume of water and a mass of ground coffee, the apparatus comprising:

a brewing chamber for containing the ground coffee and allowing the water to pass therethrough;

a ground coffee supplier for dispensing ground coffee to the brewing chamber;

a water supply for supplying water to the brewing chamber; and

a controller adapted to:

control the ground coffee supplier and the water supply such that the coffee beverage portion is brewed in a plurality of brewing steps, wherein each brewing step comprises passing a fraction of said volume through the chamber so as to contact a further fraction of said mass, the controller being configured to, in each brewing step, control the ground coffee supplier to dispense said further fraction to the brewing chamber, and wherein the controller is adapted to implement the plurality of brewing steps sequentially.

The present invention is partly based on the realization that the diterpene, i.e. kahweol and cafestol, content in a coffee beverage brewed by passing water through a brewing chamber containing ground coffee can be reduced by lowering the velocity of the water through the chamber. This can be realized by reducing the flow rate of the water for a given brew chamber geometry. The flow rate is defined as the volume of water divided by the time it takes to pass through the chamber. The use of the word ‘further’ in the term ‘further fraction’ (of the mass) is simply used to distinguish this term from the term ‘fraction’ (of the volume).

This apparatus takes longer to prepare a given volume of coffee than a conventional apparatus, in that the water flow rate is reduced, and this reduced flow is applied only to a fraction of the ground coffee. The coffee is thus prepared in multiple stages. For example, the flow rate may be halved and the coffee may be prepared in two stages, each stage using half of the ground coffee required for the eventual full coffee volume (which is termed “a coffee beverage portion”). By providing multiple stages, the taste is preserved in that the ground coffee is only brewed for the desired amount of time, which remains constant even though the flow rate has been reduced.

Brewing the coffee in this way ensures that the parameters linked to diterpene (water velocity) is reduced and that the parameters linked to taste (contact time, coffee/water ratio) remain the same as brewing the full coffee volume in one go.

The coffee beverage portion is made from a volume of water and a mass of ground coffee beans. The controller operates the apparatus to achieve a particular brewing time (i.e. the time water is in contact with the ground coffee) by selecting a suitable water flow rate, based on, for instance, the volume, mass, desired strength of the coffee beverage portion etc. Accordingly, this brewing time may ensure that the coffee beverage portion has the desired taste characteristics.

The controller controls the ground coffee supplier and the water supply to implement a plurality of brewing steps. The time period for each brewing step is equal to the brewing time. However, each brewing step utilizes a fraction of the volume of water and a further fraction of the mass of ground coffee beans. Thus, the volume of water employed for each of the brewing steps is less than the total volume for the full coffee beverage portion. Accordingly, the flow rate of the water through the chamber, and the ground coffee contained therein, is lower for each of the brewing steps than, for instance, the scenario in which the entire volume is passed through the mass of ground coffee in a single brewing step during the same brewing time.

In this manner, a coffee beverage is produced having the desired taste characteristics, due to the defined brewing time being used for each brewing step, but with a lower diterpene content due to the lower flow rate in each of the brewing steps as compared to the single brewing step scenario. Moreover, this solution may be implemented in existing coffeemaker designs without requiring any physical modification of their components, such as enlarging the opening to the brewing chamber.

A ratio between the fraction and the further fraction may be equal to a further ratio between the volume and the mass. Accordingly, the taste characteristics of each coffee aliquot produced by each brewing step, and the resulting coffee beverage portion in which the aliquots are combined, may match those of the product of a single brewing step using the same overall mass and volume, and the same brewing time.

The fraction may be half of the volume and the further fraction may be half of the mass. Thus the controller implements a simple two-brewing step process resulting in a coffee beverage portion having a lower diterpene content.

The water supply may be adapted to supply heated water. Brewing coffee may be facilitated by use of heated water due to more facile extraction of various compounds from the coffee beans. A temperature of the heated water may be the same for each of the plurality of brewing steps. The same brewing conditions may thus be used in each of the brewing steps as, for instance, for a single brewing step process using this heated water. Accordingly, the coffee beverage portion may have comparable taste characteristics with respect to those of the product of such a single brewing step process.

The apparatus may comprise a discharge for releasing the ground coffee from the brewing chamber. The controller may be adapted to control the discharge to release the further fraction following the respective brewing step. By releasing the used ground coffee following the respective brewing step, the brewing chamber may be vacated for further brewing steps. This may enhance the control which may be exercised over the taste characteristics of the coffee beverage portion, i.e. since fresh ground coffee replaces spent ground coffee for each brewing step.

The controller is adapted to implement the plurality of brewing steps sequentially. Such sequential implementation of the plurality of brewing steps may, for instance, be appropriate when the apparatus comprises a single brewing chamber.

The apparatus may comprise a plurality of brewing chambers, each having a respective ground coffee supplier and a respective water supply, wherein the controller is adapted to implement at least some of the plurality of brewing steps concurrently in the plurality of brewing chambers. In this manner, the coffee beverage portion may, for instance, be prepared in a shorter time.

The apparatus may comprise a user interface adapted to enable user input of parameters relating to the coffee beverage portion. The user interface may be adapted to enable user input of information relating to the volume and/or the mass. The controller may define the brewing time using this information.

The user interface may be adapted to enable user input for selecting brewing with a plurality of brewing steps, or brewing with a single brewing step. In this way, the apparatus is able to perform more rapid conventional brewing with a single brewing step or the slower multiple step brewing method to reduce the diterpene content.

The apparatus then implements different water flow rates in the two different modes. Different flow rates may be implemented by using a controllable valve between the water supply and the brewing chamber, or by controlling the water delivery pump, for example by applying duty cycle control.

The apparatus preferably comprises a beans chamber for receiving coffee beans and a grinding arrangement for grinding the beans to provide the ground coffee. By incorporating the grinder in the apparatus, the requisite grind size of the coffee beans may be provided, i.e. for each of the respective brewing steps, such that the requisite taste characteristics of the coffee beverage portion may be attained.

According to a further aspect of the present invention there is provided a method of preparing a coffee beverage portion from a mass of ground coffee and a volume of water in a brewing chamber, the method comprising: brewing the coffee beverage portion in a plurality of brewing steps, wherein each brewing step comprises passing a fraction of the volume through the brewing chamber so as to contact a further fraction of the mass during a time period equal to the brewing time.

A ratio between the fraction and the further fraction may be equal to a further ratio between the volume and the mass. Accordingly, the taste characteristics of the coffee aliquot produced by each brewing step, and the resulting coffee beverage portion in which these aliquots are combined, may match those of the product of a single brewing step using the same overall mass and volume, and the same brewing time.

At least some of the plurality of brewing steps are implemented sequentially, e.g. in a single brewing chamber.

