Main page
New page
Upload file
Help
Community portal
Recent changes
Talk
Contributions
Create account
Enable dark mode
Enable read mode
Log in
View history
What links here
Related changes
Page information
Editing
Coffee Processing (Practical Action Technical Brief)
(section)
From Appropedia
Warning!
You are not logged in.
Log in
or
create an account
to have your edits attributed to your username rather than your IP, along with other benefits.
Anti-spam check. Do
not
fill this in!
== Instant coffee == To produce an instant coffee, the soluble coffee solid and volatile compounds have to be extracted and then dried into a powder or granules. The production of instant coffee is unsuitable for small-scale enterprises as it requires expensive machinery such as an extractor and a freeze- or spray-drier. However a general description is provided below. === Prestripping === Sometimes the volatile compounds in coffee (of which there are over 700) are removed before the extraction of soluble coffee solids. This is usually done by passing steam through a bed of ground and roast coffee. The initial steam pressure has to be high enough for the steam to pass through a static bed of coffee. The extracts and steam are condensed to give a mixture of water and volatile compounds. These compounds can be condensed and collected using a tubular condenser with chilled water flowing through it. [[File:coffee processing percolation batteries.jpg|thumb|150px|right|Figure 4: Percolation batteries]] === Extraction of soluble coffee solids === The extraction of soluble coffee solids is usually done using water as the solvent. Extraction is continued until the solution obtained is 15-25% w/w coffee extract. The extraction is usually done at 175ºC since at 100ºC the extracted solids are difficult to dry. There are three ways the solids can be extracted. === Percolation batteries === This is the most common method. The roasted and ground coffee is held in a series of 5-8 vessels. Hot water is passed through the vessels and, when the soluble coffee solids have been fully extracted from each vessel, it is isolated from the battery and spent coffee discharged. A new vessel replaces this exhausted vessel (see Figure 4). As the extraction takes place at 175ºC, the system needs to be under pressure. A solution of 15-25% w/w of soluble material is produced which can then be dried. === Countercurrent system === Coffee is fed continuously into the bottom of an inclined cylindrical vessel and moved upwards by two helicoidal screws rotating at 10-22 revolutions per hour. Hot water enters the top and the extracted solids in solution exit at the bottom. The vessel is pressurised and kept at 180ºC by the use of temperature jackets. === Slurry extraction === Coffee and water are agitated together in a tank and separated using a centrifuge.
Summary:
Warning!
All contributions to Appropedia are released under the CC-BY-SA-4.0 license unless otherwise noted (see
Appropedia:Copyrights
for details). If you do not want your writing to be edited mercilessly and redistributed at will, then do not submit it here! You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource.
Do not submit copyrighted material without permission!
Cancel
Editing help
(opens in new window)
This page is a member of a hidden category:
Category:Pages with no lead text
Cookies help us deliver our services. By using our services, you agree to our use of cookies.
OK
Discussion