#Coffee Monday – Physical changes during roasting

Good morning people!
What do you prefer today? Maybe fruity flavor of cinnamon roast or deep and dark full city roast? What’s the difference? What should we focus on as far roasting is concerned? Today short guide throw physical changes during roasting.

Color changes

The first visible change is change of color during process as “drying phase”. During the first few minutes of roasting, degradation of chlorophyll causes beans to change color from green to yellow.

Classic definitions  and names of roast degree

These beans were photographed at 1-minute intervals during preparation of French roast. Tan and brown color are caused mostly by Maillard reactions. After “first crack” (we distinguish two of them) brown color deepens due to carmelization. Carbonization, however,  turns the beans black.

UNROASTED
 Green beans – 22 °C (72 °F),
Green coffee as it arrives at the dock. The beans can be stored for approximately 12–18 months in a climate controlled environment before quality loss is noticeable.

Drying – 165 °C (329 °F)
During the drying phase the beans are undergoing an endothermic process until their moisture content is evaporated, signifying first crack.

Set featured image

 

LIGHT ROAST
Cinnamon roast – 196 °C (385 °F), 
A very light roast level which is immediately at first crack. Sweetness is underdeveloped, with prominent toasted grain, grassy flavors, and sharp acidity prominent.

Light roast or New england roast coffee  – 205 °C (401 °F) Moderate light brown, but still mottled in appearance. A preferred roast for some specialty roasters, highlights origin characteristics as well as complex acidity.

 

MEDIUM ROAST
American roast – 210 °C (410 °F)
Medium light brown, developed during first crack. Acidity is slightly muted, but origin character is still preserved.

City roast –  219 °C (426 °F)
Medium brown, common for most specialty coffee. Good for tasting origin character, although roast character is noticeable.

DARK ROAST
Full city roast – 225 °C (437 °F)
Medium dark brown with occasional oil sheen, roast character is prominent. At the beginning of second crack.

Vienna roast –  230 °C (446 °F)
Moderate dark brown with light surface oil, more bittersweet, caramel flavor, acidity muted. In the middle of second crack. Any origin characteristics have become eclipsed by roast at this level.

French roast – 240 °C (464 °F)
Dark brown, shiny with oil, burnt undertones, acidity diminished. At the end of second crack. Roast character is dominant, none of the inherent aroma or flavors of the coffee remain.

Italian roast-  245 °C (473 °F)
Nearly black and shiny, burnt tones become more distinct, acidity nearly eliminated, thin body.

Spanish roast – 480 °C (708 °F)

Extremely dark brown, very shiny, charcoal tones dominate, flat.

 

Photo: wikipedia.org (Dan Bollinger)

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