ITC InfraMation - = March 2003

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March=20 2003

Volume 4, Issue=20 3

In This=20 Issue:=20 (Use=20 these links for Fast Navigation)

Welcome from the Editor
Coffee=20 Roasting at Home
Meet the=20 Staff - Jay Bowen
Last Month's Brainteaser

Brainteaser of the Month
Past=20 Issues
Upcoming Classes
About the = ITC

Welcome [top]

Hi=20 {{user("firstname")}},

Happy St. Patricks = day!
St.=20 Patrick is the patron saint of engineers and thermographers too! = Remember=20 the AGA 110 Thermovision "Infragreen" thermal imaging units of the = early=20 1980's?

We have a=20 feature this month, a = link to=20 view past issues of our newsletter. Enjoy!

Click here to download a pdf version of this=20 newsletter.

Until next month,

Gary=20 Orlove,
Editor and Publisher

Coffee = Roasting at=20 Home = [top]

Dr. Bob=20 Madding
Director, ITC

Two things steered me towards roasting coffee at = home. The=20 first is I really love coffee, but am not supposed to drink a lot = of=20 it. So, when I drink it, I want to drink really good = coffee. =20 The second factor is I am cheap. Perhaps frugal is a better=20 word. Designer coffee houses such as Starbucks serve a = pretty good=20 product, but you pay for it. And if you buy fresh roasted coffee, = it too=20 is expensive. I have come to believe also that the phrase = =93fresh=20 roast beans=94 is an oxymoron. Roasted coffee beans stay = fresh for=20 about two weeks, tops. You can vacuum pack it, you can put = it in the=20 freezer, you still have about two weeks. Can you drink = month-old=20 coffee? Sure, but it won=92t taste as good as week-old = coffee. =20 How long does this stuff sit on the shelf before you buy it? Then = I found=20 out green (unroasted) coffee beans stay fresh for up to two = years! =20 And they are less than half the price of roasted beans! =

Surfing the web really paid = off. =20 Turns out there are several places that sell green coffee beans = and=20 roasting supplies for the small operation and pocketbook to = match. =20 My favorite, and this is a shameless, unsolicited plug, is http://www.sweetmarias.com/ = . =20 They describe where the coffee came from, what it tastes like and = how to=20 roast it for best results. I started with a small roaster = with about=20 2 oz capacity and now roast =BD pound at a time. Compare to = commercial=20 roasters at coffee shops that roast 25 pounds per = batch.

So, what does hobby coffee = roasting have=20 to do with IR thermography? In a word: temperature. = Coffee=20 beans need to be brought to the right temperature in the right = amount of=20 time to give a flavorful product. Different varieties of = beans roast=20 differently, are of a different size and so on. Coffee = roaster=20 technology has evolved to provide the right amount of heat to all = the=20 beans efficiently, at least in theory. One methodology is a = drum=20 roaster such as the =BD lb. capacity Alpenr=F6st I use shown in = the figure=20 below.

The photo on the left shows = the roaster=20 with its access door open. Inside is a mesh drum that = rotates to=20 stir the coffee beans. At the end of the cooling cycle, the = drum=20 reverses direction allowing internal vanes to dump the roasted = beans into=20 a container on the left side. At the bottom is an electric = heater. =20 The exhaust on the right allows air drawn in from the left to=20 escape. When the cooling cycle is reached, an internal gate = opens=20 and a large volume of air is drawn through by a blower. = Invariably,=20 smoke is produced by this or any other roaster. Good = ventilation is=20 necessary for home roasting. I put my roaster in a clean = fireplace=20 and vent up the chimney in the winter and roast outside on the = deck in the=20 summer.

The infrared image on the = right shows the=20 exterior of the roaster in operation with the door closed. = There is=20 a gradient from left to right indicating direction of air flow = through the=20 machine.

The infrared image below shows the coffee inside the drum = at the=20 beginning of the cooling cycle to estimate the final roast=20 temperature. According to Davids (see reference below), if = the=20 internal bean temperature stays below 390=BAF, =93the flavor oils = stay=20 undeveloped and the coffee will taste grassy, sour and will be = without=20 aroma.=94 Should the internal temperature soar above = 480=BAF, =93most of=20 the flavor oils will have been burned out of the bean and the = woody parts=20 of the bean itself may be charred. Such coffee tastes = thin-bodied,=20 burned and industrial.=94 Within this 90F=BA span, the = coffee roast=20 ranges from a light =93Cinnamon=94 to a =93Dark = French=94.

The coffee=20 used for this test was a Kenya AA Kiawamururu Auction Lot '02 = roasted=20 about 15 seconds into the "second crack" (see below). The = resulting=20 temperature was about 444=BAF, yielding a "full city" roast, just = the way we=20 like it at the ITC. In lieu of temperature measurement, coffee = roasters=20 rely on their senses of color, smell, time and hearing, yes = hearing. The=20 Alpenr=F6st has no viewing capability short of opening the door = which cannot=20 be done without compromising the roast. Sound and experience are = the keys.=20 Between 380=BAF and 400=BAF, the "first crack" occurs. This sounds = a lot like=20 popping corn, indicating the onset of pyrolysis, or the internal=20 transformation of the bean. Stopping now will give the lightest = roast one=20 would want. For those who prefer a darker roast, we often wait = until the=20 onset of the "second crack" which sounds a lot like frying bacon. = This=20 occurs at a temperature between 415=BAF and 435=BAF. Roasts beyond = second=20 crack are the darker roasts. Experience with individual coffee = types and=20 the roaster play a key role in success. I keep records of what = coffee I=20 roast, how long I roast it and what the results were.

Though the=20 home coffee roaster will never buy an infrared camera to check the = process, industrial roasters have done so. Infrared thermography = has been=20 used to evaluate coffee roaster afterburners, finding such = problems as=20 refractory failure, flame distribution problems, air/fuel ratio = problems=20 and so on. In terms of process control, thermography may = eventually play a=20 role through use of automated IR. If an IR camera could readily = view the=20 coffee beans while roasting, what better way to evaluate the = thermal=20 conditions? IR imagery can readily capture thousands of swirling = coffee=20 beans in the act, a trick not possible with thermocouples. =

For further=20 reading, a great reference on home coffee roasting for the = beginner is=20 Kenneth Davids=92 Home Coffee Roasting. He discusses = history and=20 how-to in a clear, concise manner. I have been roasting for four = years=20 now, and I feel like there is still so much more to learn about = the=20 fascinating world of coffee. And I think infrared thermography can = and=20 will play a much larger role in coffee roasting machine design, = production=20 and maintenance.

Meet the Staff - Jay = Bowen [top]

Jay=20 Bowen
Instructor =96 ITC Level II

The ITC welcomes = Jay Bowen, our=20 newest instructor. Jay has been involved in the electrical trades = since=20 1977 and has an Associates Degree in Electronics Technology. Jay = holds a=20 Wisconsin Masters certificate and a State designer=92s license in = electrical=20 systems.

He = has been=20 using infrared thermography as a condition monitoring tool since = the=20 mid-90s . He recently led Encompass Services Corp. CM Programs, = teaching=20 and expanding service groups=92 roles by offering services = including=20 thermography inspections across the U.S. Jay developed and taught = classes=20 in thermography, motor control, power quality, instrumentation, = and=20 PLC.

Last = Month=92s=20 Brainteaser [top]

Last = month's=20 Brainteaser evoked a plethora of responses ranging from an = elephant's ear=20 to infected tooth to a volcano, but nobody guessed the right = explanation.=20

These images=20 show an old coal pile that developed hot spots due to oxidation = buried=20 deep in the pile. The hot areas probably started by spontaneous=20 combustion, one of the most frequent reasons for coal fires. The = term=20 'spontaneous combustion' means that coal can start to burn without = any=20 recognizable outer influence. It is caused by coals ability to = react with=20 oxygen contained in the air. As = a result=20 of the oxidation process the temperature of the coal starts to = rise. If=20 the temperature reaches a certain temperature noxious gases are = produced=20 such as carbon dioxide. Finally, if the temperature still = continues to=20 rise the coal reaches the flash point and starts to burn.=20

This image=20 shows a bulldozer pushing out the hot spots. Congratulations to = Marty=20 Nelson from JEA in Jacksonville, FL who took the thermograms and = stumped=20 us all.

Brainteaser of the=20 Month =20 [top]

Here is this month's brainteaser. First = reader to=20 email me with the correct explanation wins $20 in Infrabucks. = Please put=20 "Brainteaser" as the subject of the = message.

Click=20 here to email your=20 guess

Past = Issues =20 [top]

Click the links = below to view=20 past issues of this newsletter:

All past issues from February 2000 through = December=20 2002

February 2003

January=20 2003

December 2002

November=20 2002

Upcoming=20 Classes =20 [top]

Click the links = below to see our=20 latest course calendars.

Americas

EurAsia

Germany

France

About the = Infrared=20 Training Center =20 [top]

The Infrared Training Center offers training and = certification in=20 all aspects of infrared thermography use. Our world-class training = facilities are located near Boston, Massachusetts, USA and = Stockholm,=20 Sweden and have the world's most extensive hands on laboratories = for=20 infrared applications. Please join us in exploring the fascinating = world=20 of the infrared!

Your comments and suggestions about this newsletter are = welcomed=20 and encouraged. If you have an interesting application or case = study to=20 share, we encourage you to submit it for publication. Published = articles earn credit towards = recertification.

Please e-mail Gary = Orlove or=20 send regular mail to the Americas office.

Visit our website:

ITC Americas, BOSTON

16 Esquire Road
N. Billerica, MA 01862, = USA

Tel: +1-978-901-8405
Toll free:=20 = +1-866-TRAINIR
&= nbsp; =20 (866-872-4647)
Fax: +1.978.901-8832
E-mail: mailto:info_us@infraredtraining.com

ITC International, SWEDEN

Rinkebyv=E4gen 19
SE-182 11 Danderyd, = Sweden

Tel: +46 (0) 8 753 25 00
Fax: +46 (0) 8 753 26 = 01
E-mail:=20 mailto:itc@flir.se

THIS DOCUMENT IS FOR INFORMATIONAL = PURPOSES ONLY.=20 INFORMATION PROVIDED IN THIS DOCUMENT IS PROVIDED 'AS IS' WITHOUT = WARRANTY=20 OF ANY KIND. The user assumes the entire risk as to the accuracy = and the=20 use of this document. The Infrared Training Center newsletter may = be=20 copied and distributed subject to the following conditions: 1. All = text=20 and images must be copied without modification and all pages must = be=20 included; 2. All copies must contain the Infrared Training Center=20 copyright notice and any other notices provided therein;
3. = This=20 document may not be distributed for profit

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