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Roasting: Foundation

#CaffeinatedTraining

#OilSlickCoffee

@michael.c.wright

youtube.com/c/MichaelCWright

OilSlickCoffee

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Housekeeping

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Buhler at kopi Bali

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TL-3 at kopi bali

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Barth Menado at kopi bali

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Cafe De Gourmet ML-200

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US Roaster Corp., Roasters Guild Retreat

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US Roaster Corp., Roasters Guild Retreat

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Control panel; US Roaster Corp., Roasters Guild Retreat

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Control panel; 2-barrel, US Roaster Corp., Roasters Guild Retreat

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Diedrich IR2., Roasters Guild Retreat

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Control panel; Proaster (Korea), Roasters Guild Retreat

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Starbucks Roastery Reserve, Shanghai

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Starbucks Roastery Reserve, Shanghai

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Starbucks Roastery Reserve, Shanghai

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WE X Suji: Mini Roaster 100 Gram

Three Burner Types

  • Atmospheric burner (gas burner)
  • Electric burner (like toaster oven)
  • Infrared burner (ceramic plates in BBQ grill)
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Electrical burners possible on small (batch size 12 and less) roasters.

Electrical heating elements are slow but are fine for roasting.

Electricity always drives motors and general control circuits.

Heat Transfer Methods

  • Convective
  • Conductive
  • Radiative

Related:

  • Endothermic
  • Exothermic
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  • Two most common: convective and conductive.
  • Convective involves moving air.
  • Conductive requires physical contact and a temperature gradient. Drum rotation important here

Radiated heat example: the light emitted from a red-hot heating element in a toaster

Keywords: Convection Conduction Endothermic Exothermic

Safety

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Be Proactive

  • Create an emergency plan ahead of time
  • Discuss the plan with everyone
  • Create a cleaning + maintenance plan
  • Regularly review procedures and plans

Image: SCAA Heritage Material

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Personal Safety Concerns

Four areas of concern:

  • Green coffee storage
  • Roasting
  • Packaging, production
  • Shipping

What are some concerns in these areas?

Image: SCAA Heritage Material

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Loading coffee (heavy weight over head, maybe on stool, etc)

Smoke in roasting (ventilation, as smoke does escape the roaster into the room)

Product Safety Concerns

Same four areas of concern:

  • Green coffee storage
  • Roasting
  • Packaging, production
  • Shipping
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Seawater contamination during transport

Rocks in green coffee

Reacting to roaster fires

  1. Relax and calm down
  2. Shut off gas (or element if electric)
  3. Keep drum rotating
  4. Can spray into charge door
  5. Don’t eject beans
  6. Monitor bean temp, drop < 93°C
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Movie time!

Marty Curtis has over 40 years experience in rebuilding Roasters & Pollution Control Equipment.

He attended training and put in the time necessary to know how to deal with Roasting System fires with safety in mind.

Anyone who watches these videos and thinks they are ready to do what Marty does are mistaken in their assumption.

Marty Curtis WILL NOT assume any liability, with anyone, who tries to intentionally create a roaster fire as depicted in these videos.

You assume ALL RISKS & LIABILITY for any actions you undertake in this regards.

Respectfully,

Marty G. Curtis CEO Artisan Coffee Group Ltd

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Fire Classifications

  • Class A
    Ordinary items (wood, paper, plastic, rags)
  • Class B
    Flammable Liquids
  • Class C
    Electrical equipment

Image By Karta24, GFDL or CC-BY-SA-3.0, via Wikimedia Commons

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Roaster Cleaning & Maintenance

  • Remove chaff often (fuel source for fire)
    • Know where chaff collects in your roaster
    • At least daily, more for “chaffy” beans
  • Keep ducts clear/clean (creosote & chaff)
  • Keep moving parts lubricated (food grade grease)
  • Follow manufacturer’s manual and recommendations
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Quick Review

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What are the three different types of burners?

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What are the three different types of burners?

Atmospheric, electric, and infra-red

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What are four areas of safety concern?

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What are four areas of safety concern?

  1. Green Coffee Storage
  2. Roasting
  3. Packaging & Production
  4. Shipping
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How do you handle a fire in the roaster?

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How do you handle a fire in the roaster?

1. Relax and calm down

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How do you handle a fire in the roaster?

1. Relax and calm down

2. Shut off gas (or element if electric)

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How do you handle a fire in the roaster?

1. Relax and calm down

2. Shut off gas (or element if electric)

3. Keep drum rotating

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How do you handle a fire in the roaster?

1. Relax and calm down

2. Shut off gas (or element if electric)

3. Keep drum rotating

4. Can spray into charge door

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How do you handle a fire in the roaster?

1. Relax and calm down

2. Shut off gas (or element if electric)

3. Keep drum rotating

4. Can spray into charge door

5. Don't eject beans

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How do you handle a fire in the roaster?

1. Relax and calm down

2. Shut off gas (or element if electric)

3. Keep drum rotating

4. Can spray into charge door

5. Don't eject beans

6. Monitor bean temp. Drop when below 93°C

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Physical changes in the bean

  • Dries out
  • Progressively darkens
  • Becomes increasingly brittle
  • First Crack
  • Size can increase 30 - 100%
  • Second crack
  • Eventually oil seeps out (especially beyond second crack)
  • Sometimes get divots (can be a roast defect)
  • Rapid cooling (≤ 4min) to halt chemical reactions (changes)
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Discuss free water. The Vapor wall or bubble.

Discuss exothermic flashes

Contributes to the flick and crash

With slow cooling: less acidity, increased baked flavors

First Crack and Second Crack

  • Every successful roast has a first crack
  • First crack is the result of rapid release of pent-up vapor/steam pressure and CO2
  • Not all roasts reach second crack (operator’s preference)
  • Exothermic flashes as escaping heat affects environment
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bean-magnified

Cracks caused by internal pressure

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bean-magnified

Cracks caused by internal pressure

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bean-magnified

Seam separation and charring of material

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bean-magnified

Cracks, seam separation, and charring of material

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bean-magnified

Significant structural damage

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bean-magnified

Cracks, some surface charring, and oil seepage

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bean-magnified

Cracks, some surface charring, and oil seepage

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bean-magnified

Slight tipping and charring. Blown-out embryo

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bean-magnified

Cracks and charring

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Roast Data

Measurements that can be collected from green and roasted coffee:

  1. Green: batch weight
  2. Green: bulk density
  3. Green: volume
  4. Green: screen size
  5. Green: moisture content (acceptable range for Specialty?)
  6. Roasted: color
  7. Roasted: weight*
  8. Roasted: bulk density*
  9. Roasted: volume*

Cupping data should be associated with roast profile for post-roast analysis.

*Calculate percent changes for these attributes

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Label the following

ChargeFirst Crack
Turning PointSecond Crack
Color Change (Green to yellow)Roast End

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Draw profile on board, label phases & discuss RD

Roast Progression

Generally speaking:

  • Lighter roasts highlight (preserve) acidity, enzymatic flavors/aromas

  • Darker roasts emphasize chocolatey, nutty, bitter flavors/aromas

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Activity: Visually ID Roast Stages

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https://www.coffeelabequipment.com/Color_Selector_cl.pdf

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Temperature Midway Point ≈ 75 Agtron

  • Relatively new concept to SCA curriculum
  • Generates easy color to work/train with
  • Not meant to be a standard or a sweet spot regarding end product

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Don’t break your head over it

Not intended to be a standard or a sweet spot or anything significant outside of training

Easy color to work with from a training perspective

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221-193=28

28/2=14

14+193=207

The Flavor Wheel

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SCA Flavor Wheel

https://sca.coffee/research/coffee-tasters-flavor-wheel

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Umbrella Terms General Terms Specific Terms

Whitespace indicates relationship

Enzymatic Flavors & Aromas

Enzymatic Flavors

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Maillard Flavors and Aromas

Maillard flavors

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Defects

Defects

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World Coffee Research Lexicon

The terms used in the new flavor wheel come from the WCR lexicon.

Descriptive

  • No “good” or “bad” attributes (unbiased)
  • Not for ranking coffee
  • Purely descriptive

Quantifiable

  • Uses an intensity scale of 1 - 15
  • Allows for easy comparison of two or more coffees

Replicable

  • When used properly, tasters from all over the world will experience and describe the same coffee the same way
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End of presentation

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