WO1996028038A1

WO1996028038A1 - Process for the preparation of deacidified coffee

Info

Publication number: WO1996028038A1
Application number: PCT/US1996/003096
Authority: WO
Inventors: Eugene N. Bilenker; Marc A. D. Simone
Original assignee: The Great Atlantic And Pacific Tea Company, Inc.
Priority date: 1995-03-09
Filing date: 1996-03-06
Publication date: 1996-09-19
Also published as: AU5185596A; CA2214857A1

Abstract

The invention relates to a process for treating coffee prior to domestic or institutional brewing of a ground or roasted form of the coffee to form a beverage from the coffee to lower the acidity of the beverage made from the coffee. This process comprises treating the coffee with ammonia gas or ammonium ions wherein the degree of beverage acidity lowering is determined by a mass proportion of ammonia gas or ammonium ions to the coffee treated and recovering coffee having reduced acidity. The invention further relates to the reduced acidity coffee obtained from the invention process.

Description

PROCESS FOR THE PREPARATION OF DEACIDIFIED COFFEE

FIELD OF INVENTION

The field of this invention is coffee processing and methods of treating coffee so that a brew made from the roasted and ground coffee contains less acidity than the untreated counterpart .

BACKGROUND OF THE INVENTION

Many people are concerned with the acidity of their food and drink. A measure of this concern is the extensive consumption of antacids in various forms. According to a survey by Supermarket Business (46th Annual Consumer Expenditures Study Vol 48 No.9 September 1993 p.83) , a trade publication, the 1992 total sales in all retail outlets, of antacids in across-the-counter non prescription forms, was $1,082,262,000. This expenditure included such forms as effervescent antacids, liquid antacids, powder antacids, and antacid pills, gums, and lozenges . Many such acidity concerned consumers deny themselves full enjoyment of coffee beverages because of the acid nature of coffees.

Coffees differ according to the variety, origin, and processing. For variety, examples are Brazils, Colombians, Centrals from Honduras, from Guatemala, and from Mexico, Robustas from Africa, and Conillons from Brazil. There are new crop, and old crop, and there are several quality grades in each coffee. Coffees reach the consumer as regular (undecaffeinated) , decaffeinated and partially decaffeinated, each with or without added flavorings. Some people may find some of these excessively acidic.

No one has provided to the public a roasted coffee, undecaffeinated or decaffeinated, which when brewed combines the following features:

1. The beverage acidity is at a specified reduced level, or is neutral, or is at a specified alkaline level. 2. The consumer's coffee experience substantially is characteristic of the particular type of coffee when grinding the beans, brewing, and consuming the beverage.

No one has demonstrated processes for the reduction of coffee acidity using exclusively ammonia gas and/or the ammonium ion quantitatively to result in a less acid, a neutral, or an alkaline beverage.

It is an object of this invention to demonstrate the use of ammonium ions and/or gaseous ammonia, as they are available in a variety of physical states and molecular compounds, to reduce the level of acidity of coffee.

It is a further object of this invention that only water where needed as a processing aid, and those molecules, ions, or compounds functioning as neutralizers of acidity, be the sole additives to coffee beans, or to roasted and ground coffee.

It is a further object of this invention to treat the coffee so that the beverage brewed from its roasted and ground form is at a targeted reduced level of acidity.

It is a further object of this invention to treat coffee for a neutral beverage.

It is a further object of this invention to treat coffee for a beverage at a targeted level of alkalinity. SUMMARY OF INVENTION

This invention provides processes for the reduction of coffee acidity utilizing the respective acidity neutralizing capacities of ammonia, and/or ammonium ions. Illustrative, non-limiting examples of sources of ammonia and ammonium ions include :

1. Ammonia NH₃

2. Strong Ammonia Water, such, for example, a solution of 28% to 29% NH₃ by weight in water;

3. Diammonium hydrogen phosphate (NH₄)₂HP0₄;

4. Ammonium carbonate, a mixture of ammonium bicarbonate, NH₄HC0₃, and ammonium carbamate, NH,COONH₄, containing 30 to 34% NH₃ by weight;

5. Ammonium bicarbonate, NH₄HC0₃; and 6 • Ammonium carbamate, NH₂COONH₄

In this invention coffee in various stages of preparation, green, partially roasted, roasted, roasted and ground may be treated to reduce their acidity.

Either undecaffeinated, and decaffeinated coffees may be treated to reduce their acidity and coffees before flavoring or after flavoring may be treated.

In this invention each treatment may be combined with other treatments. For example a particular lot of roasted coffee beans may be divided into sublots for treatments, for example, one sublot treated with Ammonia gas, another sublot treated with Ammonium bicarbonate to be blended at an appropriate point further in the coffee operations, as for example, roasted bean with roasted bean, roasted bean with ground coffee, or ground coffee with ground coffee.

In this invention an acid reduced coffee may be blended with a non acid reduced coffee to standardize to a target level of acidity.

In this invention the strong Ammonia Water may be diluted to a lesser strength to be used for a desired level of acidity reduction.

In this invention the solid compounds, for example, Diammonium hydrogen phosphate, Ammonium carbonate, or Ammonium bicarbonate may be used directly as solids in contact with the coffee, or as water solutions in contact with the coffees, or in combination of water solution and solid in contact with the coffee. On a particular lot of coffee a single one of the acidity reducing substances may be used to reduce coffee acidity or two or more may be used to accomplish reduction of acidity.

DETAILED DESCRIPTION OF THE INVENTION

The treatments of the invention substantially retain the essential nature of the coffee experience. By this is meant providing the various styles of roasted coffee, for example, regular, decaffeinated, flavored regular, and flavored decaffeinated in typical forms, including beans to be custom ground in the store, to be ground on consumer premises, or prepackaged, roasted and ground, to be followed by customary domestic or institutional brewing procedures, and any modes of consumption, for example, black, or with whitener, with or without sugar, or in a variety of recipes.

The respective acidity reducing treatments of the invention are compatible with delivering the coffee to the consumer in all packaging modes, for example, can, paper bag, gas barrier vacuum packed, gas barrier film package with prior nitrogen or other gas flush, or gas barrier film package with a special valve which exhausts gas pressure from within the package but does not allow gas from the outside to flow into the package.

The invention provides acidity reducing treatments for any appropriate stage, ranging from beans as green, partially roasted, fully roasted, and fully roasted and ground coffees. Methods are provided that are adjustable to achieve any desired level of acidity reduction, ranging from slight reduction of beverage acidity, to alkaline beverages.

Reduction in acidity literally means reduction in the concentration of hydrogen ions which impart acidity. In a water solution a hydrogen ion is an atom of hydrogen with a positive charge due to a loss of an electron. It is designated as H⁺ . To measure H⁺ concentration an electrode is immersed in the water solution, to give a reading in pH units. Examples of pH are pH 1 for a 0.36% solution of hydrochloric acid, (muriatic acid) , a strong acid, and pH 13 for a 0.40% solution of sodium hydroxide (soda lye) , a strong base. A pH of 7 is neutral, under pH 7, acid, and over pH 7 alkaline. Vinegar has a pH of about 3; milk 6.5 to 7; pure water, completely neutral at pH 7, sea water, on the alkaline side, pH 8.5 to 10.

The pH is defined as the logarithm, to the base 10, of the reciprocal of the hydrogen ion concentration.

Mathematically this is expressed as follows: pH = log 1 . 10 [H+] The brackets [] signify concentration. Since pH is an exponential function, what appears to be a small numeric change may represent a very large change in the concentrations of hydrogen ions, the ions of acidity, as compared to [OH^"] , hydroxyl ions, the ions of alkalinity. This can be seen from the following.

pH Ratio of [H⁺] or [OH^*]

Value Concentration to that of Pure Water at 22°C 1 1,000,000

Acid side 2 100, 000

(excess 3 10,000

[H^""] ions) 4 1,000

5 100

6 10 Neutrality 7 1 8 10 9 100

10 1,000

11 10,000 Alkaline 12 100,000 side 13 1,000,000 (excess

[OH^*] ions)

The change in acidity resulting from a particular treatment may be expressed as a percentage . In the examples of acidity reduction treatments the pH of the beverage made from the treated coffee is compared to the pH of the beverage from the untreated coffee. The brewing method in these examples is standardized to 65 U.S. fluid ounces of hot water per 60 grams of ground coffee.

Brewing is by passing hot water through the ground coffee on a paper filter. A portion of beverage from the untreated coffee is allowed to cool to 25°C and the pH is determined by glass electrode. Similarly taken is the pH of beverage from the treated coffee. The percent reduction in acidity is calculated as in the following example:

Untreated Coffee Beverage pH = 5.3

Calculation of hydrogen ion concentration, [H⁺] pH = log 1 = 5.3 10 [H⁺]

1 = ant ilog 5 . 3 = 199526 . 23

[H⁺ ]

[H⁺] = 0 . 000005012

Treated Coffee

Beverage pH = 6.5

Calculation of hydrogen ion concentration, [H⁺] pH = log _!__ = 6.5 10 [H⁺]

1 = antilog 6.5 = 3162277.7 [H⁺]

[H⁺] = 0.000000316

Calculation of % reduction in acidity: Regular Coffee, [H⁺] 0.000005012 Treated Coffee, [H⁺] 0.000000316 Difference [H⁺] 0.000004696 (reduction in acidity)

Percent reduction = 0.000004696 X 100= 93.7'

0.000005012

Of course where the beverage of a treated coffee s neutral, pH 7, there is 100% reduction in acidity. Where the beverage of a treated coffee is alkaline, for example, pH 7.3, the treatment has proceeded beyond the 100% reduction in acidity to an excess of hydroxyl ion [OH^'] concentration.

EXAMPLES

The following examples illustrate certain embodiments of the present invention. The examples are not meant to limit the invention beyond what is claimed below.

EXAMPLE 1

To 200 grams of roasted undecaffeinated Colombian coffee beans 5.2 grams of water were added to raise bean moisture to 6.0%. The moistened beans were transferred to a vessel which then was sealed, followed by opening an inlet valve to feed in 1.7 grams of ammonia gas. The valve then was closed and the vessel was held, sealed, at 23°C room temperature for 1.5 hours. Then the vessel was opened, and the coffee beans were spread on a screen in a 100°C hot air oven for 1.25 hours. The coffee beans then were removed, cooled to room temperature and ground. Beverage brewed as described and cooled to 25°C read pH 6.97. The corresponding untreated coffee beverage read pH 5.41. Accordingly the decrease in acidity calculates to 97.2%.

EXAMPLE 2

In 200 grams of roasted decaffeinated Colombian coffee beans 5.2 grams of water was added to raise bean moisture to 6.0%. The moistened beans were transferred to a vessel which then was sealed, followed by opening an inlet valve to feed in 1.6 grams of ammonia gas . The valve then was closed and the vessel held, sealed, at 23°C room temperature for 1.5 hours. Then the vessel was opened and the coffee beans spread on a screen in a 100°C hot air oven for 1.25 hours. The coffee beans then were removed, cooled to room temperature and ground. Beverage brewed as described, and cooled to 25°C read pH 6.76. The corresponding untreated decaffeinated coffee beverage read pH 5.25. Accordingly the decrease in acidity calculates to 96.9%.

EXAMPLE 3

To 200 grams of roasted and ground undecaffeinated Colombian coffee 5.2 grams of water were added to raise moisture to 6.0%. The moistened ground coffee was transferred to a vessel which then was sealed followed by opening an inlet valve to feed in 1.6 grams of ammonia gas. The valve then was closed and the vessel held, sealed, at room temperature of 23°C for 0.5 hours. Then the vessel was opened and the ground coffee spread on a screen in a 100°C hot air oven for 0.5 hours. The ground coffee then was removed and cooled to room temperature. Beverage brewed as described, and cooled to 25°C read pH 6.56. The corresponding untreated coffee read pH 5.41. Accordingly the decrease in acidity calculates to 93.2%.

EXAMPLE 4

Two hundred grams of Central American green undecaffeinated coffee beans were sealed in a vessel which then was opened to a vacuum pump, subjecting the beans to 30 pounds per square inch gage of vacuum. The vacuum pump connection was sealed off and an ammonia gas inlet opened to feed in 4.7 grams of ammonia gas. The ammonia valve then was closed and the sealed system held at room temperature of 23°C for 2.5 hours. The vessel then was opened and the green beans spread on a screen in a 100°C hot air oven for 0.5 hours. The beans then were removed to cool to room temperature, and then transferred to an air quench roaster to be roasted, and then ground.

Beverage brewed as described, and cooled to 25°C read pH 6.15. The corresponding untreated green Central was similarly roasted, ground, and brewed for a beverage pH at 25°C of pH 5.41. Accordingly the decrease in acidity calculates to 81.8%.

EXAMPLE 5

To 200 grams of roasted undecaffeinated Colombian coffee beans 7.7 milliliters of strong ammonia water solution (29% by wt . of ammonia gas) were added and the container sealed. The contents were shaken frequently until all free liquid was absorbed. After 3.0 hours the container was opened, the beans spread onto a screen which then was held in a 100°C air oven for 1.5 hours. The beans were removed, cooled to room temperature, and ground. Beverage brewed as described, and cooled to 25°C read pH 6.85. The corresponding untreated coffee beverage read pH 5.26. Accordingly the decrease in acidity calculates to 97.5%.

EXAMPLE 6

To 1500 grams of roasted and ground undecaffeinated coffee 59.6 milliliters of strong ammonia water solution (29% by wt. of ammonia gas) were added and the container sealed. The contents were shaken frequently until all free liquid was absorbed. After 3.0 hours the container was opened, the ground coffee spread onto a screen which then was held in a 100°C air oven for 1.5 hours. The ground coffee then was removed, and cooled to room temperature. Beverage brewed as described and cooled to 25°C read pH 6.80. The corresponding untreated ground coffee beverage read pH 5.53. Accordingly the decrease in acidity calculates to 94.6%.

EXAMPLE 7

To 200 grams of roasted decaffeinated Colombian coffee beans 7.7 milliliters of strong ammonia water solution (29% by wt . of ammonia gas) were added and the container sealed. The contents were shaken frequently until all free liquid was absorbed. After 3.0 hours the container was opened, the beans spread onto a screen which then was held in a 100°C air oven for 1.5 hours. The beans were removed, cooled to room temperature, and ground. Beverage brewed as described and cooled to 25°C read pH 6.87. The corresponding untreated decaffeinated coffee beverage read pH 5.25. Accordingly the decrease in acidity calculates to 97.6%.

EXAMPLE 8

Sixty grams of roasted and ground undecaffeinated Colombian coffee were mixed with 1.67 grams of diammonium hydrogen phosphate powder. A beverage was brewed as described above and cooled to 25°C to read pH 6.51. The corresponding untreated roasted and ground coffee beverage read pH 5.38. Accordingly the decrease in acidity calculates to 92.6%.

EXAMPLE 9

One hundred grams of undecaffeinated roasted Colombian beans were mixed in a closed container with 2.6 milliliters of water. The contents were shaken frequently until free liquid was absorbed. After 45 minutes the moistened beans were ground. The ground coffee was mixed in a closed container with 3.4 grams of Ammonium bicarbonate for 45 minutes, followed by brewing as described above. The cooled, 25°C beverage tested pH 7.39, an alkaline coffee. The beverage made from the corresponding untreated coffee tested pH 5.47.

EXAMPLE 10

To 100 grams of roasted undecaffeinated Colombian coffee beans 2.6 milliliters of water were added followed immediately by Ammonium bicarbonate powder. The container was closed and placed in a 100°C oven for 20 minutes, and then held, closed, for 25 minutes at 24°C. The contents were ground and a beverage was brewed as described above, cooled to 25°C, giving a test reading of pH 6.64. The corresponding untreated coffee beverage tested pH 5.47. Accordingly the percent reduction in acidity calculates to 93.2%.

EXAMPLE 11

Two hundred grams of roasted, undecaffeinated Colombian coffee beans were mixed in a closed container with 5.2 grams of water for 45 minutes. The contents were shaken frequently until free liquid was absorbed. Ammonium carbonate lumps were broken to a fine powder and 5.4 grams were added to the beans with thorough mixing by shaking the closed container. The sealed container was placed in an oven at 80°C. After one hour the powder visually decreased. At two hours, the container obviously was under high pressure stress. The container was opened to relieve the pressure and then resealed to return to the 80°C oven for an additional two hours by which time the powder had disappeared. The beans then were transferred to screens and placed in a 100°C oven for 75 minutes. The contents then were cooled to room temperature, ground, and a beverage brewed as described above. Cooled to 25°C the beverage tested pH 6.80. The beverage from the corresponding untreated bean tested pH 5.47. Accordingly the percent reduction in acidity calculates to 95.3%.

EXAMPLE 12

A portion of the roasted and ground, undecaffeinated, treated Colombian coffee of EXAMPLE 1 was held 28 days at room temperature in a loosely sealed bag. Similarly, untreated, undecaffeinated roasted and ground Colombian coffee was held 28 days at room temperature in a loosely sealed bag. Beverages made as described above tested pH 6.97 for the treated coffee, and pH 5.21 for the untreated coffee. To demonstrate that precise levels of acid reduction may be achieved by blending treated coffee of high pH with more acid, untreated coffee of low pH, a 75/25 blend was made of the two coffees as follows: Treated Coffee pH 6.97 17.3 grams Untreated Coffee pH 5.21 5.7 grams The blended mixture was brewed as described above. The resulting beverage when cooled to 25°C tested pH 6.49. Relative to pH 5.21, pH 6.49 represents a 94.8% reduction in acidity. ALL EXAMPLES

In each of the examples, EXAMPLES 1 TO 12 inclusive, the essential nature of the coffee experience was retained including the quality of the treated roasted beans, the quality of treated roasted and ground beans, and the quality at each step thereafter, grinding, brewing, and the cup aroma and taste. This applied whatever the acidity reducing treatment point, green beans, roasted beans, or ground roasted coffee, undecaffeinated or decaffeinated.

Each of the roasted coffee bean and/or roasted and ground coffee bean final products of each of the treatments in EXAMPLES 1 to 12 was packageable in any mode with full lowering of acidity retainable through normal shelf conditions of time and temperature. This includes but is not limited to can, paper bag, gas barrier vacuum packed, gas barrier film package with prior nitrogen or other gas flush, or gas barrier film package with a special valve which exhausts gas pressure from within the package but does not allow gas from the outside to flow into the package.

Claims

What is claimed is :

1. A process of treating coffee prior to domestic or institutional brewing of a ground or roasted form of the coffee to form a beverage therefrom to lower an acidity of the beverage made therefrom, said process comprising treating the coffee with ammonia gas or ammonium ions wherein a degree of beverage acidity lowering is determined by a mass proportion of ammonia gas or ammonium ions to the coffee treated and recovering coffee having reduced acidity for subsequent domestic or institutional brewing.

2. A process according to claim 1 wherein a percent lowering of beverage acidity is from about 1/10 of one percent to about 100 percent as compared to beverage from untreated coffee.

3. A process according to claim 1 wherein the beverage from the treated coffee is substantially neutral.

4. A process according to claim 1 wherein the beverage is alkaline pH.

5. A process according to claim 1 wherein the coffee is treated in a closed system to prevent escape of ammonia gas and the treating is conducted at temperatures of about 0°C (32°F) to about 160°C (320°F) .

6. A process according to claim 5 wherein the coffee is treated with ammonia gas for a period from about 5 seconds to about 16 hours.

7. A process according to claim 6, further comprising ventilating the coffee at from about 0°C to about 160°C for a period of from about 5 seconds to about 16 hours after treatment with ammonia gas.

8. A process according to claim 7 wherein the ventilation comprises ventilation with nitrogen.

9. A process according to claim 1 wherein the coffee is undecaffeinated coffee or decaffeinated coffee.

10. A process according to claim 9 where the coffee is green beans.

11. A process according to claim 9 where the beans are partially roasted.

12. A process according to claim 9 where the beans are full roasted.

13. A process according to claim 9 where the coffee is roasted and ground coffee.

14. A process according to claim 10 where the green beans are conditioned to a moisture content between about 7% and about 20%, by weight, prior to treatment with ammonia gas or ammonium ions.

15. A process according to claim 11 where the beans are conditioned to a moisture content between about 0.5 and about 13%, by weight, prior to treatment with ammonia gas or ammonium ions.

16. A process according to claim 12 where the beans are conditioned to a moisture content between about 0.5% and about 13%.

17. A process according to claim 13 where the roasted and ground coffee is conditioned to a moisture content between about 0.5% and about 13%, by weight, prior to treatment with ammonia gas or ammonium ions .

18. A process according to claim 5, further comprising evacuating the closed system before feeding in the ammonia gas.

19. A process according to claim 5, wherein the ammonia is generated by transferring ammonia from an ammonia water source atmosphere space to the coffee chamber space.

20. A process according to claim 5, comprising generating ammonia by thermal decomposition of an ammonium compound.

21. A process according to claim 20 where thermal decomposition occurs at temperatures from about 50°C (122°F) to about 160°C (320°F) .

22. A process according to claim 20 where the ammonium compound is ammonium carbamate, ammonium bicarbonate or ammonium carbonate.

23. A process according to claim 1 wherein treatment is in a closed system to prevent loss of ammonium ions through evolution of ammonia gas in equilibrium with the ammonium ions at temperatures of about 0°C to about 160°C.

24. A process of preparing a coffee from which a beverage brewed from a ground mixture of the coffee will have a lowered acidity comprising dispersing in the coffee a finely divided solid ammonium compound wherein the lowered acidity is determined by mass proportion of ammonium compound to the coffee being treated.

25. A process according to claim 24, wherein the resultant percent lowering of beverage acidity will be between about 1/10 of one percent to 100%.

26. A process according the claim 24, wherein the resulting coffee beverage is a neutral pH 7.

27. A process according to claim 24, wherein the coffee will result in a beverage that is alkaline, at a pH in excess of 7.0 and as high as about pH 10.

28. A process according to claim 24 where the coffee is undecaffeinated or decaffeinated.

29. A process according to claim 28 where the coffee is roasted beans.

30. A process according to claim 28 where the coffee is roasted and ground coffee.

31. A process according to claim 24 where the ammonium compound is dia monium phosphate, ammonium carbamate, ammonium carbonate, or ammonium bicarbonate.

32. A process of preparing a coffee from which a lower acidity beverage can be made, said process comprising mixing a coffee treated to reduce the acidity of a beverage prepared therefrom with an untreated coffee wherein the degree of acidity lowering is determined by the mass proportion of treated coffee that is mixed with untreated coffee.

33. A process according to claim 32 where the resultant percent lowering of coffee beverage acidity is as low as about 1/10 of one percent to 100 percent.

34. A process according to claim 32 where the beverage from the treated coffee is a neutral pH 7.

35. A process according to claim 32 where the beverage from the treated coffee is alkaline at a pH in excess of 7.0 up to about pH 9.9.

36. A process according to claim 32 where the coffees are undecaffeinated or are decaffeinated.

37. A process according to claim 36 where the coffees are roasted beans.

38. A process according to claim 36 where the coffees are roasted and ground coffees.

39. A process according to claim 36 where prior acid reduced roasted and ground coffee is mixed with untreated roasted beans.

40. A process according to claim 36 where the prior acid reduced roasted bean coffee is mixed with untreated roasted and ground coffee.

41. A coffee prepared by the process according to claim 1.

42. A coffee prepared by the process according o claim 24.

43. A coffee prepared by the process according to claim 32 .

44. A process according to claim 7 wherein the ventilation comprises ventilation with air.