class: title, center, middle .logo[] # Roasting: Intermediate \#CaffeinatedTraining \#OilSlickCoffee <i class="fab fa-instagram"></i> <a target="_blank" href="https://www.instagram.com/michael.c.wright/">@michael.c.wright</a> <i class="fab fa-youtube"></i> <a target="_blank" href="https://youtube.com/c/MichaelCWright">youtube.com/c/MichaelCWright</a> <i class="fab fa-facebook-square"></i> <a target="_blank" href="https://www.facebook.com/oilslickcoffee">OilSlickCoffee</a> Presented: November 29th, 2018 Host: <a target="_blank" rel="noopener noreferrer external" title="5758 Facebook" href="https://www.facebook.com/5758CoffeeLab/">5758 Coffee Lab</a> Location: Bandung, Indonesia .footnote[ Press "h" for keyboard shortcuts for this presentation] --- .logo[] # Heat Transfer * Thermal Energy * Heat ≠ Temperature * Conduction, Convection, Radiation --- .logo[] # Conductive Transfer * Physical contact + temperature gradient * Common cause of roast defects * Temperature gradient inside bean * Water content is critical* --- .logo[] # Convective Transfer * Air as a medium or vehicle * Most common transfer method in drum and air roasters * Greater the temp difference between air and bean greater the transfer (potential) --- .logo[] # Radiated Transfer * Electromagnetic radiation (same as the sun) * Some visible, some not * Example: light from heat source, heat felt near a heat source * Metal in roaster acts as a battery, storing energy as heat* --- class: pic  .footnote[ https://upload.wikimedia.org/wikipedia/commons/a/a9/Hot_metalwork.jpg fir0002 | flagstaffotos.com.au [GFDL 1.2 (http://www.gnu.org/licenses/old-licenses/fdl-1.2.html)], from Wikimedia Commons] --- .logo[] # Heat Transfer, Supplemental 1. Drum, Air, Bean 2. Air, Drum, Bean 3. Bean, Drum, Air .footnote[ Terry Davis, "The Heat is On, A Roaster's Guide To Heat Transfer," Roast Magazine May/June 2009] --- .logo[] # Temperature Midway Point ≈ 75 Agtron * New concept * Generates easy color to work/train with * Not meant to be a standard or a sweet spot regarding end product  --- class: pic # Calculate TMP  --- .logo[] # Quick Review 1. What are the three types of heat transfer? 2. Why is water content important? 3. What is the difference between heat and temperature? --- .logo[] # The Roasting Cycle * Evaporation * Color VS roast curves * Defects * Cooling Time --- .logo[] # Drying * Primary concern of first-third of roast (first phase) * Evaporative cooling --- .logo[] # Roasting * Maillard reaction (complex) * Streker degradation (complex) * Melanoidins * Organic acids .center[Much more on this tomorrow] --- .logo[] # Rate of Change * Often called Rate of Rise (but rate may not always rise) * Speed (momentum) of the roast * Typically measured in 30 or 60-second intervals * Not useful until after TP * 30s is more accurate than 60s calculations --- .logo[] # Rate of Change Example: At 4:00 temp is 148°C At 4:30 temp is 153°C The temperature increased 5° in thirty seconds 153° - 148° = 5° Therefore, RoC is 5°/30s Or if we want a more accurate/higher resolution RoC we could calculate the rate of change per second: 153° - 148° = 5° Time = 30s 5/30 = .16°/s (not very useful, in my opinion) --- class: pic  --- .logo[] # Cooling * Preferably within 4 minutes * Ideally as fast as possible * Quenching with water can be bad (but can be done) --- .logo[] # Quick Review * How much mass is typically lost during the roast and what is most of the ‘material’ that is lost? * Which occurs first (and thus longest); Strecker degradation or the Maillard reactions? * Why are darker roasts less acidic? --- .logo[] # Basic properties and changes * Coffee is organic! * Endothermic VS exothermic reactions Important changes to observe and measure: * Temperature over time * Volume * Weight * Color * Density --- class: center, middle .logo[] Activity: Visual ID Roast Stages --- .logo[] # Temperature over time * Temperature evolution * Typically includes bean and air or environment temp 
(BT & ET) * Momentum (Rate of change or rate of rise) --- .logo[] # Volume Changes * Cell walls become brittle * Water vapor inside bean creates a vapor “wall”* * CO2 build-up * Other organic gasses --- .logo[] # Weight Changes * Weight difference is a critical measurement * Weigh coffee before and after roasting and calculate % weight loss * Density change is also a good measurement to track consistency --- .logo[] # Color changes * Sugar browning * Melanoidins * Industry standards for color measurement --- .logo[] # Sugar Changes * Simple sugars already present in green bean * Broken down and used later to form polysaccharides * Caramelization * Maillard VS Caramelization --- .logo[] # Acidity Changes * Acids created early in roast * Get reduced later in roast * Therefore acidity provides information on roast level .center[ More on acids tomorrow!] --- .logo[] # Workspace Management Green coffee storage, ideal conditions: * 60% relative humidity * Green beans at 10-12% moisture content 
(12% = longest shelf life with 60% relative humidity) * Keep bags ~15cm off floor, away from pests, water, etc * Consider GoPro bags (can be expensive) * Routinely check and monitor condition of stored greens --- .logo[] # Workspace Management Ideal safety conditions * Production flow * Efficiency, organization in layout & movement * Physical safety/health (heavy lifting) * Air quality while roasting * Big roasting machine (20+Kg) consider a mask * When handling greens consider a mask * Not just gases, but micro-fibers & micro-particles from greens * Fire safety * Fire suppression * Plan for a roaster fire * Share the plan with everyone * Revisit the plan regularly (at least yearly) --- .logo[] # Roaster Machine Construction * Drum roaster * Fluid bed * Batch VS continuous roaster --- .logo[] # Ventilation * Within the drum, ventilation creates convection heat transfer * Keep the exhaust stack clean to avoid fires! * Ensure dangerous gases are evacuated from facility --- .logo[] # Electricity * Electric roasters are fine for sample roasting or lab roasting. * Electrical heating elements are slow and don’t scale well Question: how would you compensate for the lag caused by an electrical heating element? --- .logo[] # Tools for roasting * Buckets + shovel/scoop * Logging sheets or software * Timer and temperature probes * Infrared thermometer can be helpful * Moisture, density, and roast color meters are handy 
(and getting cheaper and smaller) * Quality Control System (what does this look like?) *A roaster (obviously) --- .logo[] # Cleaning, Maintenance, & Troubleshooting * Ventilation ducts * Chaff collector * Exhaust air cleaning * Cooling tray * Area surrounding roaster --- .logo[] # Tomorrow We’ll meet in the cupping lab We’re cupping immediately after a quick meeting * No perfumes, colognes or heavy fragrances * Be done smoking in time for your clothes to air-out --- .logo[] # Roasting Activity: 5 Roasts Roast 1: Perform roast with any profile to Temperature Midway Point (sample color creation). Roast 2: Perform roast with similar profile to Midway Point of Roast 1 but continue to the start of 2nd Crack (and thereby resulting in a longer development time). Roast 3: Roast coffee to the same profile to First Crack, then end at the same color with a longer development time (over 4 mins). Roast 4: Roast coffee to the same profile to First Crack, then end at the same color with a shorter development time (under 1:30). Roast 5: Roast coffee to the same profile to First Crack, then end at the same color with a 2-3 minute development time. --- class: center, middle ## Value 4 Value If you found this content useful, please consider [supporting my work](https://oilslickcoffee.com/support/?utm_source=caffeinated-training&utm_medium=blog&utm_campaign=support). I charge no set fee or price for providing this. You can help keep information like this openly accessible by matching the value you received in the content; value 4 value. [Ko-fi](https://ko-fi.com/Z8Z8LX14) **/** Bitcoin Wallet: 32SW9kcAsJdZvQKBazhLUZBSD9YS8DDqe8 <a href="https://oilslickcoffee.com/support/?utm_source=caffeinated-training&utm_medium=blog&utm_campaign=support">Learn more</a> --- class: center, middle .logo[] End of presentation