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The effect of bean origin and temperature on grinding roasted coffee.

Uman E, Colonna-Dashwood M, Colonna-Dashwood L, Perger M, Klatt C, Leighton S, Miller B, Butler KT, Melot BC, Speirs RW, Hendon CH - Sci Rep (2016)

Bottom Line: Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates.We find that the particle size distribution is independent of the bean origin and processing method.Furthermore, we elucidate the influence of bean temperature on particle size distribution, concluding that grinding cold results in a narrower particle size distribution, and reduced mean particle size.

View Article: PubMed Central - PubMed

Affiliation: Meritics Ltd., 1 Kensworth Gate, Dunstable, LU6 3HS, United Kingdom.

ABSTRACT
Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates. The extraction depends on temperature, water chemistry and also the accessible surface area of the coffee. Here we investigate whether variations in the production processes of single origin coffee beans affects the particle size distribution upon grinding. We find that the particle size distribution is independent of the bean origin and processing method. Furthermore, we elucidate the influence of bean temperature on particle size distribution, concluding that grinding cold results in a narrower particle size distribution, and reduced mean particle size. We anticipate these results will influence the production of coffee industrially, as well as contribute to how we store and use coffee daily.

No MeSH data available.


Related in: MedlinePlus

The roast profile for the Tanzanian Burka (Has Bean).In this case, 10 kg of the Burka coffee was roasted in a 12 kg Probat Roaster. The temperature was monitored with a probe in the headspace of the oven, and hence the hot air rapidly cools due to thermal energy transfer to the green coffee. The temperature trajectory throughout the roasting process determines the decomposition of organic materials in coffee. Three illustrative decomposition reactions are shown that are representative processes throughout the heating process. At lower temperature a chlorogenic acid (left) may decompose through either hydrolysis or pyrolysis into quinic acid, acetic acid and the phenolic compound 3,4-dihydroxybenzyl alcohol40, or quinic acid, carbon dioxide and 3,4-dihydroxystyrene4142. Oxalic acid (centre) may decarboxylate to either CO2 or in the case of incomplete combustion CO2 and formic acid19. At higher temperatures cellulose can undergo hydrolysis to smaller sugar derivatives including glucose and levoclucosan434445. Both the temperature and time determine the chemical composition of the roasted coffee: In this case, the coffee was removed from the oven after 9 m 54 s as this time was determined to result in a soluble, sweet and favourably acidic product.
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f1: The roast profile for the Tanzanian Burka (Has Bean).In this case, 10 kg of the Burka coffee was roasted in a 12 kg Probat Roaster. The temperature was monitored with a probe in the headspace of the oven, and hence the hot air rapidly cools due to thermal energy transfer to the green coffee. The temperature trajectory throughout the roasting process determines the decomposition of organic materials in coffee. Three illustrative decomposition reactions are shown that are representative processes throughout the heating process. At lower temperature a chlorogenic acid (left) may decompose through either hydrolysis or pyrolysis into quinic acid, acetic acid and the phenolic compound 3,4-dihydroxybenzyl alcohol40, or quinic acid, carbon dioxide and 3,4-dihydroxystyrene4142. Oxalic acid (centre) may decarboxylate to either CO2 or in the case of incomplete combustion CO2 and formic acid19. At higher temperatures cellulose can undergo hydrolysis to smaller sugar derivatives including glucose and levoclucosan434445. Both the temperature and time determine the chemical composition of the roasted coffee: In this case, the coffee was removed from the oven after 9 m 54 s as this time was determined to result in a soluble, sweet and favourably acidic product.

Mentions: The roast profile presented in Fig. 1 shows the measured roaster temperature as the roasting progresses for the particular Tanzanian coffee listed in Table 1. The chemical constituents of roasted coffee depend on the temperatures of green coffee molecular decomposition. The generation and concentration control of these compounds is achieved through fine tuning of the roast profile151617. Whilst most compounds in roasted coffee are likely Maillard products (an example of which is not shown in Fig. 1)18, we present various pathways that permit the formation of acids, phenolic compounds, and also the cleavage of cellulose into sugar-related products like levoglucosan. The left-most process in Fig. 1 shows an example of decomposition of a chlorogenic acid (a group of molecules contributing to 66% of the acidity in green coffee) through low temperature hydrolysis, in which the formation of products depend on the water content within the seed1920.


The effect of bean origin and temperature on grinding roasted coffee.

Uman E, Colonna-Dashwood M, Colonna-Dashwood L, Perger M, Klatt C, Leighton S, Miller B, Butler KT, Melot BC, Speirs RW, Hendon CH - Sci Rep (2016)

The roast profile for the Tanzanian Burka (Has Bean).In this case, 10 kg of the Burka coffee was roasted in a 12 kg Probat Roaster. The temperature was monitored with a probe in the headspace of the oven, and hence the hot air rapidly cools due to thermal energy transfer to the green coffee. The temperature trajectory throughout the roasting process determines the decomposition of organic materials in coffee. Three illustrative decomposition reactions are shown that are representative processes throughout the heating process. At lower temperature a chlorogenic acid (left) may decompose through either hydrolysis or pyrolysis into quinic acid, acetic acid and the phenolic compound 3,4-dihydroxybenzyl alcohol40, or quinic acid, carbon dioxide and 3,4-dihydroxystyrene4142. Oxalic acid (centre) may decarboxylate to either CO2 or in the case of incomplete combustion CO2 and formic acid19. At higher temperatures cellulose can undergo hydrolysis to smaller sugar derivatives including glucose and levoclucosan434445. Both the temperature and time determine the chemical composition of the roasted coffee: In this case, the coffee was removed from the oven after 9 m 54 s as this time was determined to result in a soluble, sweet and favourably acidic product.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834475&req=5

f1: The roast profile for the Tanzanian Burka (Has Bean).In this case, 10 kg of the Burka coffee was roasted in a 12 kg Probat Roaster. The temperature was monitored with a probe in the headspace of the oven, and hence the hot air rapidly cools due to thermal energy transfer to the green coffee. The temperature trajectory throughout the roasting process determines the decomposition of organic materials in coffee. Three illustrative decomposition reactions are shown that are representative processes throughout the heating process. At lower temperature a chlorogenic acid (left) may decompose through either hydrolysis or pyrolysis into quinic acid, acetic acid and the phenolic compound 3,4-dihydroxybenzyl alcohol40, or quinic acid, carbon dioxide and 3,4-dihydroxystyrene4142. Oxalic acid (centre) may decarboxylate to either CO2 or in the case of incomplete combustion CO2 and formic acid19. At higher temperatures cellulose can undergo hydrolysis to smaller sugar derivatives including glucose and levoclucosan434445. Both the temperature and time determine the chemical composition of the roasted coffee: In this case, the coffee was removed from the oven after 9 m 54 s as this time was determined to result in a soluble, sweet and favourably acidic product.
Mentions: The roast profile presented in Fig. 1 shows the measured roaster temperature as the roasting progresses for the particular Tanzanian coffee listed in Table 1. The chemical constituents of roasted coffee depend on the temperatures of green coffee molecular decomposition. The generation and concentration control of these compounds is achieved through fine tuning of the roast profile151617. Whilst most compounds in roasted coffee are likely Maillard products (an example of which is not shown in Fig. 1)18, we present various pathways that permit the formation of acids, phenolic compounds, and also the cleavage of cellulose into sugar-related products like levoglucosan. The left-most process in Fig. 1 shows an example of decomposition of a chlorogenic acid (a group of molecules contributing to 66% of the acidity in green coffee) through low temperature hydrolysis, in which the formation of products depend on the water content within the seed1920.

Bottom Line: Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates.We find that the particle size distribution is independent of the bean origin and processing method.Furthermore, we elucidate the influence of bean temperature on particle size distribution, concluding that grinding cold results in a narrower particle size distribution, and reduced mean particle size.

View Article: PubMed Central - PubMed

Affiliation: Meritics Ltd., 1 Kensworth Gate, Dunstable, LU6 3HS, United Kingdom.

ABSTRACT
Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates. The extraction depends on temperature, water chemistry and also the accessible surface area of the coffee. Here we investigate whether variations in the production processes of single origin coffee beans affects the particle size distribution upon grinding. We find that the particle size distribution is independent of the bean origin and processing method. Furthermore, we elucidate the influence of bean temperature on particle size distribution, concluding that grinding cold results in a narrower particle size distribution, and reduced mean particle size. We anticipate these results will influence the production of coffee industrially, as well as contribute to how we store and use coffee daily.

No MeSH data available.


Related in: MedlinePlus