Instant coffee (or soluble coffee) is a drink created by processing brewed coffee beans into a dried product. The result is an instant coffee powder or granules. Modern instant coffee is produced commercially either by spray drying or freeze drying following which, the dried instant coffee product is re-hydrated. Instant coffee is also available in concentrated liquid form. Instant coffee has some major advantages over coffee beans or ground coffee. Lower shipping costs owing to much lower weight and volume make the end product cheaper. And instant coffee has a much longer shelf life and is easier to brew. In fact instant coffee is just about the easiest hot beverage to prepare. The powder and granules do however deteriorate if not kept dry and instant coffee does eventually spoil completely if kept too long after having been opened. Buyers of very large economy sized jars of instant coffee often discover that their purchases have been a false economy if the product isn’t consumed within a reasonable time. Having been opened small amounts of moisture enters the jar and the instant coffee starts to deteriorate.
Instant Coffee Granules
History of Instant Coffee
Instant coffee was invented and patented by New Zealander David Strang in 1890. The inventor sold it under the name of ‘Strang’s Coffee’. The patent specified the ‘Dry Hot Air Process’ as its defining feature. Later a Japanese Scientist Satori Kato who was working in the United States drew attention to the instant coffee powder at the Pan American Exposition and George Constant Louise Washington (yes another George Washington) went on to develop his own process in the US shortly afterwards, going on to market it commercially in 1910. A significant advance in the coffee refining process were achieved in the 1930’s by Nescafe and they launched their famous brand in 1938. As a result of research associated with the Second World War high vacuum freeze dried instant coffee in 1938. The National Research Corporation of Massachusetts had developed high vacuum technology for medical uses in the military during the war, and when the war ended the company applied its expertise to peacetime purposes. The company took the instant coffee making process further. Nowadays instant coffee comes in granulated and powder forms packed in glass jars, sachets and tins. More recently still, instant coffee in the form of ‘coffee bags’, similar to tea bags have become available. In some countries like South Korea instant coffee premixed with sugar and non dairy creamer has become popular.
Modern Instant Coffee production
As with traditional coffee the green coffee bean is roasted to achieve its aroma and flavour before being made into the instant coffee product. The beans are placed in rotating cylinders containing gases, and when the temperature reaches 165 degrees Centigrade the roasting process begins. The process makes a popping noise similar to popcorn. These cylinders, work with between 25% and 75% efficiency and typically take between 8 and 15 minutes to complete their work. An alternative method taking less than four minutes called the ‘fluidized bed method’ is sometimes used to arrive at the final instant coffee product. It operates at lower temperatures so allows for better retention of flavour and aroma in the coffee bean. It may surprise readers to learn that decaffeinated instant coffee involves decaffeinating the bean itself before the roasting process starts. The beans the enter the extraction stage in which they are finely ground using scored rollers to crush the beans allowing them to be placed in a solution with water. The extraction stage involves water at temperatures of up to 180 degrees being added into 5-10 percolation columns. This part of the process on the route to arriving at the final instant coffee product, concentrates the solution down to between 15% and 30%.. Sometimes additional ‘freeze concentration’ or ‘vacuum evaporation’ processes are used to concentrate the liquid down further.
Freeze drying the instant coffee using the process of sublimation to remove the water is regarded as the best method of achieving the optimum instant coffee product. Although it’s more expensive than spray drying, freeze drying has become the most popular method used since mass production of instant coffee started in America just after World War Two. Freeze drying produces a better result. Spray drying generates instant coffee particles which can be too fine to be used by the consumer and have to be further steam fused in towers similar to spray dryers or alternatively be subjected to a process called ‘belt agglomeration’ to produce instant coffee particles of the right size.
Health and Instant Coffee
Instant Coffee typically has a caffeine content of around half that present in the same volume of traditionally brewed coffee of the same general type. The antioxidant (polyphenol) levels present in instant coffee is much closer to that of coffee produced directly from the roasted beans. In general it means that instant coffee might, be healthier. Furthermore instant coffee is thought to be as efficient as drip brewed coffee in reducing the risk of type 2 diabetes. At one time there were unproven accounts of instant coffee having contributed to bladder cancer in women but the current view is that instant coffee presents no such risk. It appears that early studies failed to identify bladder cancer risks already present in the groups of women examined. The suggestion that instant coffee might have been associated with bladder cancer should have been discounted from the start. No explanation for example, was ever advanced as to why only women and not men should be so affected and the studies were poorly conducted. Modern research is more reliable and instant coffee has been given a clean bill of health.
More recently however another apparently inexplicable (although not necessarily serious), physiological effect has been linked to instant coffee. If instant coffee is consumed during, or up to 1 hour after a meal the body appears to absorb less iron. However if the coffee is consumed 1 hour before the meal no decrease is noted. On the face of it this would create a potential iron deficiency issue in people who consumed instant coffee during or after every meal. But there does not however appear to be much in the way of reported iron deficiency amongst instant coffee drinkers. It might be that there’s more than enough iron in the foods we eat to overcome this effect. No medical practitioners at the moment are suggesting that persons should refrain from drinking instant coffee for reasons of iron deficiency alone. On a different and happier note no human reproductive related effects associated with drinking instant coffee have been identified, although there are some suggestions that bone calcification might be delayed when extremely large volumes of instant coffee are consumed. The chemical ‘acrylamide’ is present in both instant coffee and brewed coffee but the same chemical is also widely present in many other foods. Acrylamide is thought to have various theoretical health risks but none are thought a significant problem in terms of instant coffee drinking.
Unusual Uses for Instant Coffee
Instant coffee has few uses in the home other than for drinking, although some use it domestically as a makeshift dye for various purposes Instant coffee is however one of the ingredients in a black and white photographic developer called ‘Caffenol C’. Experiments have shown that the lesser quality brands are better for this purpose than quality ones.