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Roasting 101 Basics
Roasting Basics

The following 'basics' primer on coffee roasting was compiled from previous posts from Seedlings

Good article covering some of the basic progressions of a roast

Heating the green coffee should bring the beans to "First Crack" also known by "1C" or "FC" in 8 to 12 minutes. Sufficiently heating coffee beans changes the internal chemical composition in a similar manner as popcorn, and as the woody material (cellulose) of the bean heats up, the moisture will be released. This produces an audible "pop" similar to popcorn, but not as loud. Each bean will crack. Like popcorn this will start with a pop or two, then steadily progress to a "rolling crack" or a persistent popping, then taper off to a pop or two until first crack has finished. The conclusion of the first crack leaves a very light roast of coffee ready for grinding and brewing. This is commonly known as a "City" roast in roasting circles. Of course the coffee can be roasted darker if desired.

If a darker roast is sought after, keep roasting, watching, listening and smelling. At the onset of 1C the aroma turns from grainy, grassy, cereal smells and wispy smoke begins to develop. By the end of 1C, smoke will grow steadily stronger as will the aromas, until "Second Crack" begins. Yes, coffee cracks once, then cracks again as the roast progresses! The onset of 2C will bring continuous and darkening smoke, a sweeter, more intense aroma, and snap-crackling. 2C sounds less like the popcorn pop, and more like the crackle of snapping toothpicks or the sound of "Rice Crispies" cereal in milk. It is quieter than 1C. 2C will begin with a snap or two as 1C did and progress to a full crackling, then if roasting continues, fade out. This second crack marks the early stages of darker roasts. Oils in the coffee will be pulled to the surface of the bean. If the roast is stopped just prior to 2C, the roast is called "Full City" and can have a few oil droplets visible on the beans. Stopping the roast further into rolling second crack will yield a "Vienna" roast and the beans should be nearly covered with shiny oil. Stopping at the end of 2C is a French Roasted, very dark coffee. Once second crack has begun, the flavor characteristics that give the coffee bean its fruitiness or acidity, or delicate floral, or sweet chocolate will be caramelized and many of them lost. The resulting dark roast will be marked more by the degree it is roasted than by the distinctness the bean was given on the tree.

----------end article

The following general guidelines are a place to start and intended to assist persons new to roasting.

Preheat your roaster

For all roaster types except fluidbeds, preheat your roaster before charging. Coffee likes to move quickly during the first few seconds of a roast. Start with enough energy to allow reaching a bean temperature of 200F or 94C in 2 minutes. Preheat to an environment temperature anywhere from 300F or 150C up to 400F or 204C. For fluidbeds, begin the roast with a hot air temperature between 300F or 150C and 350F or 175C.

To 300-310F or 150-155C (yellow) is drying phase:
Try to hit yellow somewhere between 3 1/2 and 5 minutes. Too fast brings 'grassiness' in most coffees and 'ashyness' in some low altitude beans such as Brazils, Kona etc. Too slow will flatten or mute the flavors.

Yellow to first crack:
Too fast brings higher perceived sharp acidity, slower brings nuttiness, too slow brings 'baked' flavor

First crack to finish:
Too fast tastes underdeveloped, flat. Too slow through this stage can also bring about a baked flavor.

From 300F or 150C on, the beans should NEVER drop in temperature, always increasing.

The following basic profile is a good place to start for anyone not already familiar with roasting:

-4 to 5 minutes to yellow for drum roasters, small fluidbeds and convection-only roasters can get away with less.

-4 to 5 more minutes to start of first crack 380-410F or 193-210C same as above with small fluidbeds and convection-only roasters, less time is usually allowed.

-1 to 3 additional minutes to end of roast depending on degree of roast level)**

These temperatures are typical for the three major stages of roasting but depending on your sensor type, placement and type of roaster (drum, radiant, convection only), this can vary by several degrees +/-

**For light roasts where there may only be between 15 or 20 degrees from onset of first crack to finish, one should try and allow at a minimum 1+ minutes for proper development.
Edited by allenb on 09/08/2022 11:22 AM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Those are excellent guidelines. For other new readers, they need to know that some roasters take a bit longer to hit these benchmarks (like full yellow) with roasters such as the Gene Cafe. They can still make rather excellent coffee. They can reduce the time (to yellow) by preheating the empty drum, and rapidly pulling it, filling it with the beans, and restarting.

Be sure to keep roasting logs, and be prepared to pay attention to the details, and learn from the outcomes.
Thanks for mentioning the time constraints of the Gene getting to yellow. I'm sure there are other roaster types that also take a little longer to get to end-of-dry (yellow) but will still produce excellent coffee.

Please feel free to post within this thread, any additional roaster specific tips for the Gene related to hitting good profile benchmarks as well as any other roaster types.

1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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