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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 EK 43 grinder, (a) consists of two burrs; one stationary and one mobile. The hopper-to-shoot path is linear resulting in minimal retention of ground coffee in the burrs and shoot. There are two types of burrs: Turkish, (b) and Coffee, (c). The primary differences between the two burrs are emphasised in blue in (b,c), respectively. The flat triangular ends are intended to polish the particulates. For this study we employed the Turkish burr set. Photographs taken by Spencer Webb.
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f2: The EK 43 grinder, (a) consists of two burrs; one stationary and one mobile. The hopper-to-shoot path is linear resulting in minimal retention of ground coffee in the burrs and shoot. There are two types of burrs: Turkish, (b) and Coffee, (c). The primary differences between the two burrs are emphasised in blue in (b,c), respectively. The flat triangular ends are intended to polish the particulates. For this study we employed the Turkish burr set. Photographs taken by Spencer Webb.

Mentions: The Mahlkönig EK 43 grinder, shown in Fig. 2, was selected for this study because it is designed to have minimum retention time between placing the coffee in the hopper and subsequent grinding. Like all grinders, the EK 43 burrs are replaceable and are susceptible to becoming misaligned (where the two grinding discs are not perfectly parallel). We had access to three separate EK 43 s on the day of testing; two which were fitted with so-called coffee burrs and one with Turkish burrs (Fig. 2). Burr alignment can initially be assessed audibly by closing the burr aperture with the grinder turned on, causing them to ‘chirp’. The pitch of the chirp provides insight into the alignment, with deeper chirps indicating more contact between the burrs and therefore better alignment. Assessing the smoothness and spread of ground particle distribution can also give information on burr alignment, though it is difficult and slow to reliably adjust alignment based on this information. We have provided one example of particle size distributions from a burr misalignment in Figure S1. Ultimately, we elected to use the grinder that was producing subjectively marketable espresso shots that day, as determined by a resident qualified Q-grader and shop owner (Maxwell Colonna-Dashwood)27. Experiments herein were performed with the Mahlkönig EK 43 grinder spinning at 1480 rpm and grinding with Turkish burrs.


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 EK 43 grinder, (a) consists of two burrs; one stationary and one mobile. The hopper-to-shoot path is linear resulting in minimal retention of ground coffee in the burrs and shoot. There are two types of burrs: Turkish, (b) and Coffee, (c). The primary differences between the two burrs are emphasised in blue in (b,c), respectively. The flat triangular ends are intended to polish the particulates. For this study we employed the Turkish burr set. Photographs taken by Spencer Webb.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: The EK 43 grinder, (a) consists of two burrs; one stationary and one mobile. The hopper-to-shoot path is linear resulting in minimal retention of ground coffee in the burrs and shoot. There are two types of burrs: Turkish, (b) and Coffee, (c). The primary differences between the two burrs are emphasised in blue in (b,c), respectively. The flat triangular ends are intended to polish the particulates. For this study we employed the Turkish burr set. Photographs taken by Spencer Webb.
Mentions: The Mahlkönig EK 43 grinder, shown in Fig. 2, was selected for this study because it is designed to have minimum retention time between placing the coffee in the hopper and subsequent grinding. Like all grinders, the EK 43 burrs are replaceable and are susceptible to becoming misaligned (where the two grinding discs are not perfectly parallel). We had access to three separate EK 43 s on the day of testing; two which were fitted with so-called coffee burrs and one with Turkish burrs (Fig. 2). Burr alignment can initially be assessed audibly by closing the burr aperture with the grinder turned on, causing them to ‘chirp’. The pitch of the chirp provides insight into the alignment, with deeper chirps indicating more contact between the burrs and therefore better alignment. Assessing the smoothness and spread of ground particle distribution can also give information on burr alignment, though it is difficult and slow to reliably adjust alignment based on this information. We have provided one example of particle size distributions from a burr misalignment in Figure S1. Ultimately, we elected to use the grinder that was producing subjectively marketable espresso shots that day, as determined by a resident qualified Q-grader and shop owner (Maxwell Colonna-Dashwood)27. Experiments herein were performed with the Mahlkönig EK 43 grinder spinning at 1480 rpm and grinding with Turkish burrs.

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