Coffee Troupe

Crystal Caffeine – Angel Hair

Rich Helms — Thu, 15 Dec 2011 01:57:39 +0000

Caffeine is released during roasting. Some of this caffeine crystalizes on the outside as the smoke escapes.

Temperature Probe Setup on HotTop Roaster

This is a HotTop roaster. The yellow devices on top are temperature probes. As the roast progresses, smoke escapes from the probe holder. Over time, amazingly intricate white crystal structures appear. These caffeine crystals are know as angel hair in coffee jargon.

Caffeine Angel Hair formed on the bean temperature probe handle

These are microscope shots of the crystals after removed from the probe.

Caffeine Crystals under a microscope

Same cluster under higher power.

Caffeine Crystals under higher power

Surprise Roasted Coffee Bean Degassing Discovery

Rich Helms — Sat, 10 Dec 2011 19:32:55 +0000

Degas 3 Setup

The degassing experiment three was drawing to a close. To recap 100 grams of dark roasted beans were put in one flask, 100 grams of the same beans but ground were put in the other flask. After 24 hours 294 mls of CO₂ were released from the ground coffee. Even after 3 days the ground coffee maxed out at 300 mls supporting the literature ⁽¹⁾ that ground coffee degasses in 12-24 hours depending on grind.

The whole beans were a different story. The 130 ml of day one grew to 290 mls in nine days. The literature said about 7 days for most degassing. I was getting ready to clean up the experiment when I had an idea. Just for “shits and giggles” why not grind the nine day old beans. They had stopped releasing CO₂ but was there any inside that grinding would release? Using the same grinder settings as previous experiments I ground the 100 grams and quickly returned to the flask and stoppered. I was surprised to see gas released with a similar curve to freshly roasted coffee.

In one day 112 mls of CO₂ were released. Like fresh roast beans almost all of the release was in the first 24 hours. While only 38% of what a fresh roast grind release, the total release was 406 mls versus 296 for fresh ground.

Grind Nine Day Old Beans

I have not found any literature on CO₂ degassing in older coffee. I am going to continue other degassing experiments to open up the parameters of cause/effect.

My color spectrometer has not arrived yet. Really looking forward to experimenting with it.

References:

Development of an apparatus for measuring the degassing behavior of coffee with the option to examine the influence of protective gases for aroma preservation : KOZIOROWSKI, Thomas; BAUMEISTER, Heinrich; JANSEN, Gerhard; BONGERS, Sandra; PROBAT-WERKE, Emmerich, Germany – Probat

Coffee Degassing Experiment 3 – Ground vs Whole Bean

Rich Helms — Sat, 03 Dec 2011 02:07:11 +0000

Experiment three was a chance to apply all of the lessons learned in measuring CO₂ degassing of roasted coffee.

Degas 3 Setup

Lesson 1: A photo copy stand was used to support the graduated cylinders. Fill the cylinders with water and place upside down in the tank. Lower the photo rack then support the cylinders with square wooden rods, hold with several rubber bands then raise the attached cylinders with the camera holder adjuster.

Eye Droppers on Tubing

Lesson 2: Using eyedroppers is very effective but you have to slightly point them downhill or the air will escape, just slower. The most effective dropper has a turn on the end pointing down. This made it easier to prevent gas escaping and water filling the line. The eye droppers were purchased at Walmart for $2 a pair. Keep the eyedroppers as close to the cylinder bottom without touching. Water pressure becomes a factor if you put them deep in the water.

Flask with Funnel on Scale

Lesson 3: The critical timing is from grinding the coffee, place in the flask, weigh and stopper. By putting a funnel in the flask on the scale ground coffee could be scooped quickly and accurately.

Lesson 4: I wrote a trivial program to log the time vs the readings. This meant recording readings was just typing in the levels. The program tracked the time. For the time value I used a Unix Timestamp, the number of seconds since January 1 1970 00:00:00 GMT. So to calculate offset is simple subtraction from the first reading. The data was then copy/pasted into a spreadsheet for calculations and graphing.

Costa Rica Degas Exp 3 w Degas 2 in Background

Lesson 5: Track as many variables as possible. By using Artisan I could compare degas roast 2 to degas 3 roast.

Hours	Ground ml CO2	Whole ml CO2
–	30	0
0.05	45	0
0.10	58	0
0.12	62	0
0.13	66	0
0.18	75	0
0.20	80	0
0.27	90	0
0.34	100	0
0.44	110	0
0.51	118	0
0.53	120	0
0.65	130	0
0.75	136	0
1.04	154	0
1.17	160	0
1.28	165	0
1.76	183	15
1.94	190	18
3.79	226	37
11.69	270	89
12.12	280	94
22.12	290	124
23.36	290	126
24.04	290	128
24.58	294	130
25.61	296	132
27.25	296	135
35.65	296	145
36.87	296	154
46.35	300	170
47.62		178
48.65		182
50.75		182
59.44		188
60.89		194
72.75		198
85.32		210
91.38		220
100.10		227
108.91		236
111.60		240
114.28		243
117.01		246
120.31		248
155.70		264
157.01		267
166.09		270

Hours vs ml CO2 Ground (Blue) vs Bean (Red)

Conclusion 1: Ground degassing is pretty well complete in this experiment at 12 hours. 280 ml of CO2 released at 12 hours while 300 by 48 hours. After day 3 the whole beans are still degassing but slowing down.

Next experiment is to repeat this setup but with a medium roast (430^o drop.) I also ordered a school grade color spectrometer and am investigating roast colour analysis.

Most Important Conclusion: Crawling into the raw science basics of roasting is really fun.

Ground vs Whole Bean Degassing

Rich Helms — Tue, 29 Nov 2011 01:45:06 +0000

In this experiment, I roasted Costa Rica coffee to Full city. I dropped the roast at 450^oF. While I normally do not roast so dark, I knew from documentation this would result in more CO2 to be released.

Ground on left vs Whole Bean on Right

I placed 100 grams of ground coffee in the the left flask, while 100 grams of whole beans were placed in the right flask. I loaded the ground coffee into the flask as quickly as possible, but the degassing speed surprised me. In one hour of capping the flask, 120 ml of CO2 was already released. This is much faster than whole bean degassing. In the previous whole bean experiment with a medium roast and twice the coffee it took 24 hours to release 120 ml.

Degassing CO2.

Another change from the previous setup was to add eye droppers to the end of the tubes. This made it easier to see the bubbles form. Play the video to see how fast the ground coffee released CO₂.

Eye Droppers on Tubing

Hours	ml CO₂
0	0
0.08	28
0.13	40
0.23	58
0.27	62
0.28	65
0.35	72
0.38	78
0.45	84
0.52	90
0.60	96
0.67	102
0.80	110
0.90	116
0.95	118
1.00	120
1.07	126
1.15	130
1.37	138
1.48	144
1.88	158
2.00	160
2.30	166
3.13	186
3.53	194
5.00	212
6.83	228
8.78	238
19.00	256
31.00	268

ml CO2 Released vs Hours

Roast profile from the Artisan tracking screen.

Costa Rica Roast Profile for Degas 2 Experiment

Degassing Grind w 1/16" Scale

This shot image was captured with a Celestron digital microscope. The scale on the right is 1/16″. The beans were ground with a Macap MC4.

Measuring Roasted Coffee CO2 Degassing

Rich Helms — Fri, 25 Nov 2011 00:36:58 +0000

As I read more and more on how CO₂ is released from freshly roasted coffee I decided to try my own experiment. Basically the experiment is to measure the captured CO₂ as it is released. A basic experimental approach is to use an eudiometer.

Eudiometer as shown in Wikipedia

My setup is not quite as elegant.

First Degas Measurement Experiment Setup

The purpose of this test is to try the setup. The flask is 500 ml with 211 grams (~7.4 oz.) of medium roast Costa Rica coffee. The beans were loaded 5 minutes after dump with a temperature of 94^oF. The graduated cylinder is 250ml and the tubing 1/4″ OD flexible copper. I am concerned that the inside diameter is large enough that air will escape up and water flow down. I will add a water dropper on the next version to keep water from going in and the air bubbling out. Also the tube should be shorter so that it is easier to get into the graduated cylinder.

12 hours into degassing

Hours	ml CO₂
1.4	20
3.7	29
11.7	76
13.0	80
19.0	100
22.0	112
24.0	122
24.6	124
26.0	129
36.0	152
37.0	154
46.5	172
48.0	176
49.5	180
59.5	194
61.0	200
71.0	214
84.0	224
94.5	236
104.3	246
108.0	250

ml CO2 Released vs Hours

The papers I found said the degassing would continue on whole beans for 7 days. Now that the output reached 250 ml, the capacity of the graduated cylinder, I am going to end this experiment and set up one comparing whole bean and ground coffee. To avoid the 250ml capacity I will put in 100 grams of coffee.

Vacuum Bagging Fresh Roast Coffee Beans

Rich Helms — Sat, 05 Nov 2011 14:22:50 +0000

On the commercial coffee LinkedIn group, there was a question on vacuum packing freshly roasted coffee to keep it fresh. When I was at roasting school, we learned how freshly roasted coffee gives off CO2. This is why you need a can or bag with a gas relief valve. Recently, I decided to get a hand vacuum bagging system. It is a low-cost unit available in Canada from Home Hardware for only $20. For a small cost I could experiment with vacuum packing coffee. The bags are reusable but not cheap, at about $1.25 each. As I just want to use the bags for my coffee at home, the price per bag is not a factor. If the coffee was for resale, a much lower cost per bag would be needed.

Vac N Store system from Home Hardware

The Vac N Store kit comes with three bag sizes. My sample roaster does 1/2-pound roasts that fit nicely in the small bag. By sealing the bags, the coffee is not exposed to oxygen, which is what contributes to making coffee stale. What surprised me was how much gas is released by the beans. Here is a bag of just-sealed, freshly roasted coffee. The little hand pump does a fair job of removing air, but is not commercial grade.

Vacuum bagged coffee

Here is the bag 5 days later.

Vacuum bag with released CO2

I was surprised how much air was in the bag. This is not from leaking. Here is a large bag of decaf green coffee beans that I packed several weeks ago. The vacuum seal is still tight.

Decaf Green coffee beans in vacuum bag

I put the bagged roasted coffee in my grinder this morning, and it was very nice. Did it hold the freshness better? I am not sure. I need to do a side-by-side on the same coffee, one roasted a week ago and stored, the other roasted the day before.

My question coming out of this is how do companies like Illy vacuum pack coffee? I believe theirs stays tightly packed because the coffee is ground. Perhaps on the next roasting batch, I will bag 1/2 as beans and in a second bag, 1/2 ground and see how it compares.

The ABC of the Dota Tarrazu coffee region

Rich Helms — Sun, 09 Oct 2011 19:08:05 +0000

Matias Zeledon, the coffee producer I visited last year, has written an excellent introduction to the Dota Tarrazu region of Costa Rica. This is where I studied growing coffee.

Click to read the article on Dota Tarrazu http://downtoearthcoffee.blogspot.com/

Down to Earth – Started by Mother Nature, finished by hand

Rich Helms — Sun, 07 Aug 2011 14:39:05 +0000

Walking around the village

A year ago my wife and I spent a week at the Down to Earth Coffee Plantation in Dota/Costa Rica. While I have been trained to roast green coffee beans I had no idea how coffee was grown or harvested.

We learned about everything from planting seeds to transplanting, picking, processing, drying and milling (removing the parchment).

This is an opportunity to experience Costa Rica. We lived in the local village of 300 people 45 minutes by 4×4 from the paved road.

Weighing and Hulling (Removing the Parchment)

Rich Helms — Sun, 08 May 2011 15:55:46 +0000

When the beans are at 11-12% moisture, they are removed from the parijuelas and bagged. Each bag has the parijuela number that it came from. The bags are then weighed and the results logged.

Weighing and logging the dry beans

Coffee beans have a hard shell covering the bean. Here is the coffee bean anatomy introduced in the Processing the Coffee Cherries article. This illustration from Wikipedia shows the cherry anatomy.

Coffee Bean Structure

Structure of coffee berry and beans:

centre cut
bean (endosperm)
silver skin (testa, epidermis)
parchment (hull, endocarp)
pectin layer
pulp (mesocarp)
outer skin (pericarp, exocarp)

The last step is hulling, or removing the parchment. Processing removed parts 7, 6 and 5. Hulling is the step that involves removing part 4, the parchment. Parts 3, 2 and 1 form the final green coffee bean. Some companies remove part 3, the silver skin, with a machine called a polisher. Most green coffee sold in North America has the silver skin still on.

In these three photos, we see the parchment being removed.

Dry coffee bean with the Parchment still on

A piece of the parchment shell removed

Green bean with the parchment removed

Parchment is removed with a hulling machine. Hullers work by rubbing the beans to crush the parchment, then blowing the light parchment pieces off. Hullers may also sort the beans by size.

Eureka Separator and Grader (American)

In this photo from All About Coffee (1922), by William H. Ukers, we see an old Eureka Separator and Grader.

Hulling Parchment Coffee.

This video shows a modern machine hulling coffee from Matias’ plantation. The output is sorted into two sizes: normal and one for small rejects. These rejects are usually broken beans or peaberries (a coffee pit that did not grow into two beans forming a single bean.)

The next stop for these green beans is the roaster and then a cup of tasty coffee.

Drying the beans

Rich Helms — Sun, 24 Apr 2011 15:40:40 +0000

Wet Coffee Beans just from the cherry

The product of coffee cherry processing is bags of wet coffee beans. These new beans are about 2/3 water. Green beans ready for roasting need to be 11 to 12% moisture, so a significant amount of water has to be removed.

While large commercial processors will use a power unit, small operations use the sun. Beans are spread out to dry. Most spread the beans on a concrete pad; Matias uses drying racks called parijuelas, traditional wood-framed mesh racks.

Parijuelas

The equivalent of 10 cajuelas, half of a fanega, of cherries goes into the processor, and 4 cajeulas come out. This is poured into one parijuela. Once these dry and have their parchment removed, they will result in 54 pounds of green coffee. Each parijuela is labeled and the date is noted when a batch of fresh beans is added. The average drying time is seven days in the sun. In a labour intensive process, the wet beans must be moved around several times a day to avoid any rot or fungus growing. In the evening and during rain, the beans must be covered to avoid absorbing water. Two approaches are used here. In the picture above, black plastic sheets are connected to each Parijuela. This plastic is draped over the beans at night.

Parijuelas in Protective Tunnel

Another approach is to build a plastic tunnel to house the Parijuelas. This has several advantages.

There is no need to manually cover and remove the plastic at night.
The tunnel gets warmer than the outside air so drying is faster.

The down side is the tunnel is not cheap to build.

Testing Moisture with Sinar FarmPro 6090

Every day, the moisture content of each parijuela is measured and logged. This is done with a moisture meter, in this case a Sinar FarmPro 6090. This unit can measure the moisture of green beans with and without parchment, as well as roasted coffee as whole bean or ground.

Sinar FarmPro 6090

Once the coffee reaches the desired 11-12% moisture, it is bagged and stored to await the next step, parchment removal.

Measuring Bean Moisture with Sinar FarmPro 6090.