Instant coffee is a product derived from coffee beans through manufacturing processes that result in an extract of either granules, powder, or a liquid concentrate.
How Is Instant Coffee Made?
Instant coffee is made by brewing a concentrated liquid solution of real coffee and then removing the water through dehydration. The leftover residue powder is instant coffee.
Also see: The Top Ten Coffees in the World.
The History of Instant Coffee Production
Capturing the essence of good coffee flavor in an instant coffee product has been an ongoing challenge. For more than two centuries, individuals and companies have attempted to make an instant coffee that tastes and smells as good as freshly brewed whole bean coffee.
Is Instant Coffee as Good as Fresh-Brewed Coffee?
The results have been mixed. It remains to future scientists to continue to attempt to duplicate, in instant form, the best flavor of coffee when properly brewed.
In short, it's not a substitute for fresh-roasted, freshly ground and brewed coffee.
It does have its place however. While today's instant coffees have still not achieved the level of quality that would allow them to replace brewed coffee, the product still has great value - the thing about instant coffee is that, in a pinch when you can't have fresh coffee, it does the trick. Some people even prefer the “instant” taste.
Instant Coffee Production
About 40,000 tons of instant coffee are sold in the United States each year, and in some other countries instant coffee is far more popular than brewed coffee.
It All Begins with the Roasting
To make instant coffee, first the green coffee beans are roasted to bring out their tastes and aromas. The roasting is typically done in a roasting plant where the coffee beans are placed in a rotating drum with hot combustion gases.
Roasting the green coffee beans typically takes about 8 to 15 minutes at temperatures up to 165 degrees Celsius. Continuous fluid bed roasting may also be used, and this takes from 30 seconds to 4 minutes and uses lower temperatures. The benefit of the lower temperatures is better taste and aroma retention.
The Instant Coffee Process - Grinding the Coffee to Powder
Scored rollers are used to crush (not cut) the coffee beans to a finely ground to a particle size between .020 and .043 inches (.5 and 1.1 millimeters).
The roasted, ground coffee is then dissolved in water and percolates at 150 degrees to 180 degrees Celsius until the resulting concentrate is between 15 and 30 percent by mass. Then either vacuum evaporation or freeze concentration (e.g. freeze dried coffee) produces the final product.
Spray Drying During Instant Coffee Production
Spray-driers or high-vacuum equipment may be used to evaporate water from the extract of brewed coffee in the last stage of creating the powdered soluble (instant) coffee.
Spray drying involves using hot gas to rapidly dry a liquid or slurry and create a dry powder, and is one of the most economical methods of producing instant coffee (soluble coffee).
Spray drying is an ideal method for drying thermally-sensitive materials, and utilizes a relatively short drying time, avoids heat damage, and results in very fine, spherical particles about .012 inches (300 micrometers) in diameter with a density of about .22 grams per cubic centimeter.
Methods of Spray Drying during Instant Coffee Production
Spray drying includes one of several methods of nozzle atomization, which may include either high speed rotating wheels or spray wheels. The high speed rotating wheels, reach 20,000 rpm and are capable of processing up to 60,000 pounds (27 tons) of solution each hour.
Spray wheels utilize drying towers with a wide radius that prevents the atomized droplets from collecting on the wall of the drying chamber.
Nozzle Atomization During Instant Coffee Production
Nozzle atomization takes anywhere from five to thirty seconds depending on the size of the particles, the diameter of the drying chamber, and the heat applied. The coffee goes into the chamber at about 270°Celsius and 80% moisture and comes out at about 110°Celsius and 3.25% moisture.
Spray drying produces extremely fine particles which must be converted into larger particles by either belt agglomeration or by steam fusing in towers.
Making Freeze-Dried Coffee
To make freeze-dried coffee, the extract is frozen and then the water is removed by a process called sublimation - a solid transitioning directly from the solid to gas phase without the usual intermediate liquid stage.
Aromatization During the Instant Coffee Production Process
Aromatization is the process of adding aromatic flavor materials back into the soluble coffee (instant coffee) after these materials are lost during the brewing or drying process, and before the product's conversion into a soluble form.
Packaging Instant Coffee
The instant coffee (soluble coffee) is then typically packaged into cans, vacuumized sealed jars, or other sealed, airtight containers.
How to Prepare Instant Coffee
To prepare instant coffee powder or granules for consumption, just add hot water - the fancy word for this is rehydration. If the instant coffee is a liquid concentrate rather than granules or powder, then it is kept refrigerated or in aseptic packaging until it is reconstituted by adding hot water.
Specific ratios will vary between brands, but instructions typically call for 1 tsp of instant coffee per cup.
Now that you know how instant coffee is made, check out the History of Instant Coffee.