Rasa pada KOPI Roasted!

Flavour compounds in roasted coffee

Chemical compounds present in roasted coffee can be roughly grouped into volatile and non-volatile, some of the former being responsible for aroma and the latter for the basic taste sensations of sourness, bitterness and astringency (Buffo & Cardelli-Freire 2004). Russwurm reported that carbohydrates, proteins, peptides and free amino acids, polyamines and tryptamines, lipids, phenolic acids, trigonelline, and various non-volatile acids in the green coffee beans were involved in the flavour formation during roasting (Russwurm 1970). For example, chlorogenic acid contributes to body and astringency; sucrose contributes to color, aroma, bitterness, and sourness; minor protein components like free amino acids are highly reactive by interacting with reducing sugars, which make the Maillard reaction happen; triogenlline generates pyridine and may be consequently be responsible for some objectionable flavours; and caffeine can be contributed to the bitterness (Flament 2002).

Maillard reactions have been identified to be the major pathway in the formation of volatile compounds in coffee roasting (Shibamoto 1991). In the Maillard reaction, reducing sugars such as glucose or fructose react with free amino acids to form N-substituted glycosylamine adducts, which are then rearranged to aminoketones and aminoaldoses by Amadori and Heynes rearrangements. A complex reaction cascade of Amadori and Heynes rearrangement products leads to numerous volatile compounds and complex melanoidins.

More than 800 volatile compounds have already been identified in roasted coffee, among which, about 40 compounds are responsible for the characteristic aroma of coffee (Belitz et al. 2009). 

(1) Proteins, peptides and amino acids: Crude protein content is relatively stable during roasting, while the free amino acids decrease by 30%, with dark roast espresso reaching up to 50% (Belitz et al. 2009). Protein content plays an important role in espresso coffee as it affects the foamability of the beverage that the foamability increased generally with increase total protein concentration until a maximum value is reached (Nunes et al. 1997). The composition of the amino acids vary dependent on their thermal stability and reactions involved. For instance, changes in glutamic acid content are less dramatic as compared to cysteine and arginine. The latter amino acids tend to deplete rapidly during roasting due to their involvement in Maillard browning reactions (Illy & Viani 2005).

(2) Carbohydrates: Only traces of free mono and disaccharides in green coffee remain after roasting. Cellulose, hemicellulose, arabinogalactan and pectins play important roles in the retention of volatiles and contribute to coffee brew viscosity. It is reported that in espresso coffee, the foam stability is related to the amount of galactomannan and arabinogalactan (Nunes et al. 1997).

(3) Non-volatile lipids and lipid-solubles: Triglycerides, terpenes, tocopherols and sterols contribute to brew viscosity. The lipid fraction tends to be stable and survive the roasting process with only minor changes. Linoleic and palmitic acids are the predominant fatty acids in coffee. Cafestol and kahweol are diterpenes that degrade by the roasting process. Another diterpene, 16-O-methylcafestol, is present in Robusta but not Arabica coffee, making it a suitable indicator for detecting Robusta content in coffee blend (Speer et al. 1991; Belitz et al. 2009).

(4) Caffeine: Caffeine is of major importance with respect to the physiological properties of coffee, and also in determining the strength, body and bitterness of brewed coffee. The caffeine content of green coffee beans varies according to the species that Robusta coffee contains about 2.2%, and Arabica about 1.2%. Environmental and agricultural factors appear to have a minimal effect on caffeine content. During roasting there is no significant loss in terms of caffeine (Ramalakshmi & Raghavan 1999). However, caffeine content per 177 mL (6 oz) of coffee range from 50 to 143 mg, depending on the mode of preparation(Rogers & Richardson 1993; Bell et al. 1996). Bell and others (Bell et al. 1996) reported that more coffee solids, larger extents of grinding, and larger volumes of coffee prepared at a constant coffee solids to water ratio led to significantly higher caffeine content. Home-grinding yielded caffeine content similar to that of store-ground coffee, and boiled coffee had caffeine contents equal to or greater than filtered coffee (Bell et al. 1996).

(5) Acids: Acids are responsible for acidity, which together with aroma and bitterness is a key contributor to the total sensory impact of a coffee beverage. Carboxylic acids, mainly citric, malic and acetic acids are responsible for acidity in brewed coffees. Arabica coffee brews are more acidic (pH 4.85-5.15) than Robusta brews (pH 5.25-5.40) (Vitzthum 1975).

(6) Melanoidins: The final products of the Maillard reaction between amino acids and monosaccharides, are the brown-coloured substances that impart to roasted coffee its characteristic color, possess antioxidant activity, and affect on the flavor volatiles (Hofmann & Schieberle 2001; Del Castillo et al. 2002; Vignoli et al. 2011).

Source : Physicochemical Changes of Coffee Beans During Roasting

JAVA PREANGER COFFEE ADDICT

Fadillah Satria

 

FTIP TMIP UNPAD

fadilprojectkopi@gmail.com

Perubahan struktur kimia saat meroasting KOPI!

Changes in Chemical Compositions during Roasting

Roasting causes a net loss of matters in the forms of CO2, water vapor, and volatile compounds. Moreover, degradation of polysaccharides, sugars, amino acids and chlorogenic acids also occurred, resulting in the formation of caramelization and condensation products. Overall, there is an increase in organic acids and lipids, while caffeine and trigonelline (N-methyl nicotinic acid) contents remained almost unchanged (Buffo & Cardelli-Freire 2004). The main acids present in green beans are citric, malic, chlorogenic, and quinic acids. During roasting the first three acids decrease while quinic acid increases as a result of the degradation of chlorogenic acids (Ginz et al. 2000). Formic and acetic acids yields increase up to the medium roasting degree and then begin to fall as roasting is continued. According to Balzer (Balzer 2001), a rapid increase in titratable acidity during roasting was observed from green to medium roast, followed by a smaller decrease as roasting proceeded.

The reaction products formed are highly dependent on the roasting time-temperature profile used. Excessive roasting produces more bitter coffee lacking satisfactory aroma, whereas very short roasting time may be insufficient to develop full organoleptic characteristics (Yeretzian et al. 2002; Lyman et al. 2003; Buffo & Cardelli-Freire 2004). Although the majority of phenolic antioxidants naturally occurring in coffee bean are lost during roasting, the formation of other antioxidants from Maillard reactions during roasting can enhance the antioxidant activity of coffee. Compared to medium roast coffee, dark roast coffee exhibited lower radical scavenging activity than medium roasted coffee due to the degradation of polyphenol, and thus the antioxidant activity will also depend on roasting severity and type of coffee (Giampiero Sacchetti 2009).

The profile of organic compounds generated during roasting is very dynamic and complex. Using Proton transfer reaction-Mass spectrometry (PTR-MS) technique, Yeretzian et al. (Yeretzian et al. 2002) simultaneously monitored the evolution of 8 volatile compounds at isothermal conditions as a function of time. They observed a distinctive increase in acetic acid, methyl acetate, and pyrazine concentrations in the headspace, all occurred at the same time. Concomitantly, there was a rapid decrease in water vapor and methanol concentrations. Moreover, these peaks shifted in synchronous manner with the roasting condition. For instance, at 190oC, the above observed changes took place at 19 min but shifted to 30 min when the beans were roasted at 180oC (Yeretzian et al. 2002). Similar observations were observed by Hashim and Chaveron, who concluded that methylpyrazine may be used as an indicator to monitor the roasting progress of coffee beans (Hashim & Chaveron 1995). It has been suggested that the pressure buildup within intact bean cells is comparable to inside an autoclave, which can further complicated the chemical reactions occurred in coffee bean during roasting (Buffo & Cardelli-Freire 2004).

Chemical reactions happened during coffee roasting are very complex, which have not been fully understood. Based on the literature reviewed, we can conclude that the quality of roasted coffee cannot be solely described in terms of physical parameters at the start and end point of roasting, but rather it is dependent on the path taken during the roasting process. To reach a specific flavour profile, not only that precise control of roasting time and temperature is needed, the variety/quality of green beans, cooling, and degassing conditions are expected to be important as well.

Source : Physicochemical Changes of Coffee Beans During Roasting

JAVA PREANGER COFFEE ADDICT

Fadillah Satria

 

FTIP TMIP UNPAD

fadilprojectkopi@gmail.com

Meroasting Kopi!

Roasting of coffee beans

Green coffee beans provide neither the characteristic aroma nor flavour of brewed coffee until they are roasted. Moreover, the roasting process increases the value of coffee beans, by 100-300% of the raw material (Yeretzian et al. 2002). Roasting of coffee beans typically takes place at 200-240°C for different times depending on the desired characteristics of the final product. Events that take place during roasting are complex, resulting in the destruction of some compounds initially present in green beans and the formation of volatile compounds that are important contributors to the characteristic of coffee’s aroma. The chemical compositions of green, roasted, and brewed coffee are shown in Figure 1 (Barter 2004).

Briefly, as temperature increases to about 100oC, green coffee beans undergo moisture loss from 8-12% in green coffee beans to about 5% in the roasted coffee beans (Illy & Viani 1998). The smell of the beans changes from herb-like green bean aroma to bread-like, the color turns from green to yellowish, and the structure changes from strength and toughness to more crumbly and brittle. When the internal temperature of beans reaches 100oC, the color darkened slightly for about 20-60 s due to the vaporization of water. At 160-170oC, the beans become lighter in color for about 60-100 s. As roasting continues at this temperature, Maillard and pyrolytic reactions start to take place, resulting in gradually darkening of the beans (Hernandez et al. 2007). The buildup of water pressure, along with the large amount of gases generated causes the cellulose cell wall to crack, giving rise to the so called “first crack”. As heating continues at the roasting temperature (160-170oC), the coffee becomes darker and more rapid popping of coffee bean occurs (“second crack”) as the carbon dioxide (CO2) buildup exceeds the strength of the cellulosic walls of the bean. Finally, after roasting, the fresh roasted coffee beans are quickly cooled to stop roasting (Yeretzian et al. 2002).

The final quality of roasted coffee is influenced by the design of the roasters and time-temperature profiles used. Although heat transfers during roasting can involve conduction, convection, and radiation, convection by far is the most important mode of heat transfer that determines the rate and uniformity of roasting (Baggenstoss et al. 2008). Coffees roasted in fluidized-bed roaster that is almost exclusive based on convective heating can result in low density and high yield coffee (Eggers & Pietsch 2001). On the other hand, coffees roasted in drum roaster that involves mainly conductive heat transfer have less soluble solids, more degradation of chlorogenic acids, more burnt flavour, and higher loss of volatiles than the fluidized bed roasters (Nagaraju et al. 1997).

The effects of time-temperature profile on coffee aroma properties have been reported by Lyman et al. (Lyman et al. 2003). They observed that the medium roasted process (6.5 min to the onset of the first crack and 1.0 min to the onset of the second crack) resulted in good balance of taste and aroma with citrus flavour. However, the “sweated process” (4.5 min to the first crack and 6.5 min to the second crack) resulted in non-uniform bean color and the coffee was “sour, grassy, and underdeveloped”. Reducing the heating rate further by using the “baked process” (11 min to the first crack and 18 min to the second crack) produced coffee of “flat, woody with low brightness and acidity” (Lyman et al. 2003). In another study, Schenker et al. reported that LHC process (150 to 240oC in 270 s; 240oC for 55 s) resulted in the formation of the highest quantities of aroma volatiles, while the long time low temperature (LTLT) approach (isothermal heating at 220oC for 600 s) generated the lowest aroma volatiles. Moreover, the distribution of the 13 volatile compounds monitored was considerably different depending on the roasting profiles used (Schenker et al. 2002).

Depending on the extent of heat treatment, coffee can be largely categorized as light, medium or dark roasts. Light roast process tends to give non-uniform bean color with sour, grassy, and underdeveloped flavour, while medium roast process produces a balanced taste and aroma with citrus flavour. By contrast, dark roast process produces coffee of low acidity sensory profiles (Lyman et al. 2003). Physical characteristics such as temperature, color, and weight-loss are often used as indicators of roast degree. However, these parameters only allow assessment of the flavour profile for coffee roasted under narrow process conditions (Sivetz 1991; Illy & Viani 1995). Other analytical methods for quantifying the degree of roast include ratio of free amino acids (Nehring & Maier 1992), alkylpyrazines (Hashim & Chaveron 1995), and chlorogenic acids content (Illy & Viani 1995). Fobe and others (Fobe et al. 1968) studied changes in chemical composition of Arabica coffee roasted at 230°C at different process times. They reported that as the roasting time increased, the following changes occurred: (1) sugar contents first increased, and then decreased; (2) minimal change in caffeine content; (3) proteins decreased continuously; (4) free fatty acids increased; and (5) unsaponifiable compounds decreased (Fobe et al. 1968).

Source : Physicochemical Changes of Coffee Beans During Roasting

JAVA PREANGER COFFEE ADDICT

Fadillah Satria

 

FTIP TMIP UNPAD

fadilprojectkopi@gmail.com

 

All About Green Coffee Beans (Kopi Beras/Kopi Hijau)

The green coffee beans

The overall quality and chemical composition of green coffee beans are affected by many factors, such as the composition of the soil and its fertilization, the altitude and weather of the plantation, and the final cultivation and drying methods used. Coffee plants are grown in tropical and subtropical regions of central and South America, Africa, and South East Asia, mainly in regions with temperate and humid climates (Schenker 2000). Brazil is by far the largest grower and exporter of green coffee beans in the world followed by Vietnam, Colombia, Indonesia, Ethiopia and India – producing nearly 2.5 million tons of green coffee beans per year (Franca & Oliveira 2009).

The genus coffee belongs to the botanical family of Rubiaceae and comprises more than 90 different species (Davis 2001). However, only Coffea Arabica (Arabica), Coffea canephora (Robusta), and Coffea liberica are of commercial importance (Schenker 2000). Arabica accounts for approximately 64% while Robusta accounts for about 35% of the world’s production; other species with not much commercial value like Coffea liberica and Coffea excelsa represent only 1% (Rubayiza & Meurens 2005). Due to its more pronounced and finer flavour qualities, Arabica is considered to be of better quality and accordingly command higher prices (Valdenebro et al. 1999). 

Coffee cherries are harvested when they become bright-red, glossy, and firm, either by selective hand-picking or non-selective stripping of whole branches or mechanical harvesting. The hand-picking method is very time-consuming, but results in a superior product quality because only ripe cherries are selected. After harvesting, the coffee fruits are separated from the pulp, which is carried out by dry or wet processing (Clarke & Macrae 1987; Illy & Viani 1995). 

The dry process is simple and inexpensive. The whole cherries are dried under the sun in open air, followed by the separation of the hull (dried pulp and parchment) mechanically to yield the green beans. On the contrary, the wet process requires greater investment and more care, but results in a superior coffee quality. In the wet process, the pulp of the coffee cherries, which is made up of exocarp and mesocarp, is removed mechanically, but the parchment remains attached to the beans. After drying either under the sun or in a dryer, the parchment is removed to produce the green coffee beans. Bean size, color, shape, processing method, crop year, and presence of defects, are some of the parameters used to evaluate the quality of green coffee beans (Banks 2002).

Coffee cherries are harvested when they become bright-red, glossy, and firm, either by selective hand-picking or non-selective stripping of whole branches or mechanical harvesting. The hand-picking method is very time-consuming, but results in a superior product quality because only ripe cherries are selected. After harvesting, the coffee fruits are separated from the pulp, which is carried out by dry or wet processing (Clarke & Macrae 1987; Illy & Viani 1995). The dry process is simple and inexpensive. The whole cherries are dried under the sun in open air, followed by the separation of the hull (dried pulp and parchment) mechanically to yield the green beans. On the contrary, the wet process requires greater investment and more care, but results in a superior coffee quality. In the wet process, the pulp of the coffee cherries, which is made up of exocarp and mesocarp, is removed mechanically, but the parchment remains attached to the beans. After drying either under the sun or in a dryer, the parchment is removed to produce the green coffee beans. Bean size, color, shape, processing method, crop year, and presence of defects, are some of the parameters used to evaluate the quality of green coffee beans (Banks 2002). notes of the coffee blend (Parliment & Stahl 1995). Besides contributing to balanced flavour profiles, Robusta coffee is often blended with Arabica for cost reduction purpose. Robusta beans are lower in cost since the crops are more hardy to grow (more resistant to infestation) and easier to harvest (grown in regions of low elevation) than the Arabica counterpart.

Defective beans (black or brown, sour, immature, insect-damaged, split), which represent about 11-20% of coffee production, can impact the flavour of the roasted products. Mazzafera compared the chemical composition of defective beans and non-defective beans. The researcher found that non-defective beans were heavier, had higher water activity, and lower titratable acidity than the defective beans. The content of sucrose, protein, 5-caffeoylquinic acid, and soluble phenols were also higher in non-defective coffee beans (Mazzafera 1999). Nevertheless, the antioxidant level in the defective beans, especially chlorogenic acids, remains high which may be a good source of antioxidant or radical scavenger for other food applications (Nagaraju et al. 1997).

After harvesting, green coffee beans should be dried to 10-14.5% moisture content and stored below 26oC under dry environment (50-75% RH) to maintain the bean quality and to prevent the growth of mould (Gopalakrishna Rao et al. 1971; Kulaba 1981; Betancourt & Frank 1983). Under optimal storage conditions, green coffee beans may be stored for more than 3 years (Bucheli et al. 1998). Usually, green coffee beans are packaged in natural jute, sisal or burlap bags, although high quality beans may be packaged in high barrier synthetic vacuum packages fabricated from synthetic thermoplastic polymers. Cupping is a method to detect the early stages of coffee deterioration. Bucheli and others (Bucheli et al. 1996) reported that glucose was a sensitive marker for green coffee bean quality during storage. Glucose is present only in trace amount of good quality green coffee, and the content will increase when deterioration occurs (Wolfrom & Patin 1965; Bucheli et al. 1996).

Source : Physicochemical Changes of Coffee Beans During Roasting

JAVA PREANGER COFFEE ADDICT

Fadillah Satria

 

FTIP TMIP UNPAD

fadilprojectkopi@gmail.com

Introduction KOPI!

Coffee is one of the most popular beverages in the world. Nearly 25 million farmers in 50 countries around the world depend on coffee for a significant part of their livelihoods (Cague et al. 2009). Coffee is the most traded commodity second after oil (Ponte 2002). Among coffee drinkers, the average consumption in the United States is 3.2 cups of coffee per day versus 2.6 cups in Canada (Canada 2003).

A good quality cup of coffee is depended on many factors, such as the quality of green beans, the roasting conditions, the time since the beans are roasted, and the type of water used for brewing. More than 800 volatile compounds have been identified in roasted coffee, where of around 30 compounds are responsible for the main impression of coffee aroma (Baggenstoss et al. 2008).

The overall quality and chemical composition of green coffee beans are affected by many factors, such as the composition of the soil and its fertilization, the altitude and weather of the plantation, the cultivation, and the drying methods used for the beans. Coffee plants are mainly grown in tropical and subtropical regions of central and South America, Africa and South East Asia, in temperate and humid climates at altitudes between 600 and 2500 m (Schenker 2000). The genus coffee belongs to the botanical family of Rubiaceae and comprises more than 90 different species (Davis 2001). However, only C. arabica, C. canephora, and C. liberica are of commercial importance (Schenker 2000). As a result of modem breeding techniques some hybrids of C. arabica and C. canephora have recently been introduced with success. Usually roasted coffee beans from different origins are blended at specific ratios to provide coffee of unique flavour profiles. Often time, coffee beans are blended for the purpose of cost saving.

Coffee cherries are harvested each year when they are bright-red, glossy, and firm. After removing the outer hull, the seeds inside of the cherry are commonly called "green coffee beans". The quality of the green coffee beans is dictated by a number of parameters, including bean size, color, shape, method of drying, crop year, and presence of defects (crack, withered bean, bean in parchment, mouldy bean, etc.).

The unique aroma profiles of coffee are closely related to the time-temperature profile used during roasting. The roasting profiles are chosen to produce high quality coffee which are unique to specific brands and must be strictly controlled to meet consumers’ expectations. Coffee producers rely on sensory and physicochemical characteristic evaluations to assure that roasting takes place at the target process parameters. Industrial scale roasting of coffee beans is mainly achieved by conventional drum roasting, in which beans are heated with hot gas in a horizontal drum, or vertical drums equipped with paddles. Roasting time can range from 3 to 12 min, depending on the temperature used, which is typically between 230 to 250oC. By contrast, fluidized bed roasting is achieved by directing high velocity hot air towards the beans, usually from the bottom of the roaster, to suspend the beans in turbulent air. The hot air temperature ranges from 230 to 360oC (Eggers & Pietsch 2001). The roast temperature determines both flavour formation and structural product properties. Different temperature profiles affect dehydration and the chemical reaction conditions in the bean which control gas formation, browning and flavour development. In general, the use of roasting temperature of greater than 200°C is required in order to result in desirable chemical, physical, structural, and sensorial changes in the coffee beans (Clarke & Macrae 1988; Schenker 2000; Schenker et al. 2002; Baggenstoss et al. 2008). Color change and weight loss are frequently used as a measure of the degree of roast, and both are directly related to the final roasting temperature (Sivetz 1991; Illy & Viani 1995). Other methods, such as the ratios of free amino acids (Nehring & Maier 1992), and chlorogenic acids content (Illy & Viani 1995) have also been used.

Researchers have reported the effects of time-temperature profile on coffee aroma properties. In general, low-temperature-long time roast processes result in sour, grassy, woody, and underdeveloped flavour properties. In comparison, high-temperature-short-time produced the higher quality coffee in terms of producing more aroma volatiles and higher brew yield (Schenker et al. 2002; Lyman et al. 2003). Reviewing these and other literature, one can conclude that the complex changes in coffee during roasting do not solely depend on physical parameters at the start and end point of the thermal process, but rather a path-dependent phenomenon. Therefore, to gain insight into the changes of physicochemical properties of coffee during roasting, the green beans must be roasted under controlled conditions.

Source :

Physicochemical Changes of Coffee Beans During Roasting

JAVA PREANGER COFFEE ADDICT

Fadillah Satria

FTIP TMIP UNPAD

fadilprojectkopi@gmail.com

Akhir dari Meroasting Kopi - Degassing

After roasting, coffee beans are quenched to remove the residual heat quickly. This process can trap significant amount of CO2 in the bean, thereby lengthens the required time for CO2 degassing. This is a critical step that must be carried out before packaging of roasted coffee to prevent packaging failure due to pressure build up within the package. Conceivably, depending on the method of cooling used, post-roasting carbon dioxide degassing time may be shortened, or even eliminated. For instance, spraying roasted coffee with a controlled amount of water under agitation will remove the residual heat from the coffee beans rapidly due to the latent heat of vaporization of water. The humidified air may increase the rate of CO2 degas. Potentially, this process may be incorporated as part of the roasting regime towards the end of the roast cycle before ejecting the beans from the roaster. Alternatively, slower cooling at temperatures above ambient in an enclosed space will increase the diffusivity of CO2, potentially shortening the duration of the degassing step. Further investigation involving these types of innovative process inventions to shorten or eliminate CO2 degas will simplify the degas storage and packaging requirements of roasted coffee.

Source :

Physicochemical Changes of Coffee Beans During Roasting

JAVA PREANGER COFFEE ADDICT

Fadillah Satria

FTIP TMIP UNPAD

fadilprojectkopi@gmail.com

Profile Roasting Untuk Kopi Arabika (Hard Bean)

Roasting Profile for Hard Bean Coffee

For hard beans, especially when roasted beyond the second crack, I recommend an “S-curve” for the roasting process. (This is based on endless cupping trials and comparison of different roast profiles). After loading the beans into the drum, the bean probe will display a drop in temperature, which will bottom out at the turning point (TP).  Hard beans will now be roasted with high initial heat. Until the start of the first crack, the heat inside the beans is endothermic; the beans are absorbing the supplied heat. Right before the start of the first crack, the heat inside the beans becomes exothermic and the beans start generating heat. At this point the operator has to reduce energy supply in order to gain control of the roast process (point I). After about two minutes of controlling the roast with low energy supply (less BTU), the operator can again increase heat (endothermic heat; the beans are again absorbing heat) to prepare for the finish of the roast. The start of energy increase can be seen at the point where the temperature curve is rising again (point A). 

During numerous cupping trials, I have found that the ideal time between the start of the first crack and the end of the roast (I and End) is at least three minutes. The ideal roast time for solid drum roasters with
convection heat (airfl ow heat passing through the drum) is 12–15 minutes. With these roasters, roast times longer than 20 minutes will produce baked flavors; roast times shorter than eight minutes will enhance sour notes. For solid drum sample roasters, the roast time can be done in 8–10 minutes. Drum roasters using infrared heat usually allow longer roasting times without affecting the quality of the roasted coffee. Fluid-bed roasting machines, which use the concept of transferring heat through a high-velocity airfl ow at a reduced temperature, usually allow faster roasting times.
 

After learning roasting the hard way—by using sight, sound and smell—I later discovered the important value of proper measuring tools, such as probes for exhaust, environmental and bean temperature. Anyone who operates a coffee roaster can replicate the experiments I’ve completed over the past years. Learning how to roast each green bean to perfection is just the fi rst step in creating that perfect cup

Source : ROAST MAGAZINE

 

JAVA PREANGER COFFEE ADDICT

Fadillah Satria