Latest Posts

  1. Timor No Leste

    Timor No Leste

    Posted from the road, some thoughts on coffee from East Timor (Timor Leste) and working with small holder farmers.

    Read More
  2. Roasting Flores Gunung Gedha on a Popcorn Popper and Quest M3s

    Roasting Flores Gunung Gedha on a Popcorn Popper and Quest M3s

    Read More
  3. Podcast Episode #25: The Global Trade/Burundi Discussion

    Podcast Episode #25: The Global Trade/Burundi Discussion

    Some very informative audio from last month's discussion

    Read More
  4. The Flores Factor

    The Flores Factor

    Crowd pleasing coffee from a promising origin.

    Read More
  5. Six under Six - July 2019

    Six under Six - July 2019

    Six delicious coffees for under six dollars.

    Read More
  6. Coffee Roasting Demo at The Berkeley Public Library

    Coffee Roasting Demo at The Berkeley Public Library

    Read More
  7. 20% Off Guatemala Sale - Check Out Our "Cheat Sheet" Overview

    20% Off Guatemala Sale - Check Out Our "Cheat Sheet" Overview

    Take advantage of this great discount on these crowd-pleasing coffees.

    Read More
  8. A Second Look at 4 Ethiopian Coffees

    A Second Look at 4 Ethiopian Coffees

    We took a second look (and taste!) at 4 Ethiopian coffees from our 20% off sale.

    Read More
  9. Video: Sample Roasting with an Aillio Bullet R1

    Video: Sample Roasting with an Aillio Bullet R1

    Read More
  10. Intro to Home Roasting Class

    Intro to Home Roasting Class

    Learn how to roast coffee with an electric popcorn popper

    Read More
  11. Video: Guatemala 2019 Coffee Clips

    Video: Guatemala 2019 Coffee Clips

    A few fairly low tech clips and some thoughts on coffee processing and coffee buying in Guatemala.

    Read More
  12. Video: Larry Cotton's Sifter Coffee Roaster

    Video: Larry Cotton's Sifter Coffee Roaster

    Sweet Maria's Customer Larry Cotton blows our mind again

    Read More

CO-2 Decaf Method

CO-2 Decaf Method

This method uses two natural elements, pure water and carbon dioxide ( together they make "Sparkling Water") to extract caffeine from the coffee grains. This method was discovered by Kurt Zosel, a well named scientific, of the Max Plank Institute.

Steps for the C0-2 or Carbonated Water Method:

Coffee is mixed with pure water.

  • When the coffee absorbs the water the grains expand, their pores get opened and the caffeine molecules become mobile.
  • At this point carbon dioxide is added ( A 100% Natural Element) at a 100 atmospheres pressure to the pure water.
  • Basically the water and the carbon dioxide are mixed to create the sparkling water.
  • The carbon dioxide acts like a magnet and attracts all the caffeine molecules that became movable.
  • When the caffeine is captured by the carbon dioxide, this is removed.
  • The carbon dioxide is very selective and it doesn't touch the carbohydrates and proteins of the coffee beans.
  • The carbohydrates and the proteins are the ones that give the coffee the flavor and smell after it is made.
  • When the carbon dioxide has finished removing the caffeine, the coffee seeds are dried naturally
  • Carbon dioxide is then recycled and caffeine is sold for other commercial uses.

Benefits of this method:

  • Extracts Caffeine, effectivly. Is a direct contact method but does not use chemcals.
  • Doesn't chemically affect proteins or carbohydrates of the coffee beans.
  • The byproducts are natural and a 100% recyclable.

Carbon Dioxide Decaffeination Process Article

from Scientific American, June 1997
Visit their excellent web site at http://www.scientificamerican.com
Magazine subscription information, click here.

 

DECAFFEINATING
COFFEE

by Saul N. Katz
 CAFFEINE is a small, bitter-tasting alkaloid. High-quality Arabica coffee beans (the source of most specialty coffees) are typically 1 percent caffeine by weight, whereas cheaper and more bitter Robusta beans have twice that amount.

Spurred by the belief that excessive coffee drinking had poisoned his father, the German chemist Ludwig Roselius, in about 1900, found a number of compounds that dissolved the natural caffeine in coffee beans without ruining the drink's taste. Chloroform and benzene did the job but were toxic, so for 70 years methylene chloride became the solvent of choice.

When it was discovered in the 1980s to be a suspected carcinogen, the chemical was abandoned by all the big U.S. coffee labels. The Food and Drug Administration continues to permit the use of methylene chloride if the residues in the coffee are below 10 parts per million. Processing for specialty decafs still often uses it because it perturbs other flavorings so little.

Many other solvents can serve to debuzz coffee. An "all-natural" label may mean that ethyl acetate is the solvent in use, because that chemical occurs naturally in fruit. Water also works as a means of decaffeination. The so-called Swiss water process soaks green coffee beans in a solution that contains the chemical components of beans dissolved from a previous batch, except for the caffeine. Because the water is already saturated with sugars and peptides, only the caffeine passes from the beans into the water.

Another process, illustrated here, uses supercritical carbon dioxide as a solvent; in this state, the carbon dioxide is intermediate between a gas and a liquid. The variety of caffeine extraction methods demonstrates that a lot of sleepless nights have gone into helping the world get a good night's rest.


SAUL N. KATZ retired in 1989 as a principal scientist at the Maxwell House Division of General Foods. He holds several patents on the process for supercritical fluid extraction of caffeine. http://www.scientificamerican.com



1.SOAKING green coffee beans in water doubles their size, allowing the caffeine to dissolve into water inside the bean.2. CAFFEINE REMOVAL occurs in an extraction vessel, which may be 70 feet high and 10 feet in diameter, suffused with carbon dioxide at roughly 200 degrees Fahrenheit and 250 atmospheres. Caffeine diffuses into this supercritical carbon dioxide, along with some water. Beans enter at the top of the chamber and move toward the bottom over five hours. To extract the caffeine continuously, the beans lower in the column are exposed to fresher carbon dioxide, which ensures that the caffeine concentration inside beans is always higher than in the surrounding solvent. Caffeine therefore always diffuses out of the beans.

3. DECAFFEINATED BEANS at the bottom of the vessel are removed, dried and roasted.

4. RECOVERY of dissolved caffeine occurs in an absorption chamber. A shower of water droplets leaches the caffeine out of the supercritical carbon dioxide. The caffeine in this aqueous extract is then often sold to soft-drink manufacturers and drug companies. The purified carbon dioxide is recirculated for further use.

IMAGES:Michael Goodman