Instant coffee
Instant coffee is coffee already brewed, from which the factory has removed the water: all that is left is to put it back. The preparation comes down to a spoon and a cup of water, and all the know-how has passed to the manufacturing side.
What is left to do in the cup when the coffee is instant?
Start the scene or choose a stage. The animation simplifies the mechanism; what follows gives the details and the available references.
The powder is a coffee already brewed from which the water has been removed: extraction took place at the factory, at temperatures and yields that no kitchen reaches. In 1922, Ukers describes the typical factory: a battery of three to seven percolators, an evaporator and a vacuum drum dryer. At home, there is no longer any grind, filter or grounds.
Read the stages without animation
- The factory did everythingThe powder is a coffee already brewed from which the water has been removed: extraction took place at the factory, at temperatures and yields that no kitchen reaches. In 1922, Ukers describes the typical factory: a battery of three to seven percolators, an evaporator and a vacuum drum dryer. At home, there is no longer any grind, filter or grounds.
- Water meets the powderA spoonful of powder or granules, water, a stir: the grains dissolve almost instantly, in hot water as in cold, Ukers already noted. The cup is ready in a few seconds.
- The puff of aromaFrom the first contact with hot water, a cloud of odors escapes; the Swiss and Brazilian team that measured it speaks of an “aroma explosion.” Each molecule leaves at its own pace, according to its volatility and solubility; most of the aroma is released in the very first seconds.
- The cup fadesThe odor above the cup then declines: the nose perceives less and less as one drinks. It is the reverse of a filter, whose aroma renews itself as long as the cup is hot.
To remember: Instant coffee did its extraction at the factory: in the cup, all that is left is to put the water back, and the aroma leaves almost entirely in the first puff.
In history: Satori Kato, in Chicago, filed in 1901 the first American patent on a dry coffee concentrate; he was already drying the aroma separately, below 4 °C, to return it to the powder.
Read the full article and its sources ↓History
The first American patent on a dry coffee concentrate is Satori Kato's, “a subject of the Emperor of Japan” living in Chicago, filed in April 1901 and granted on August 11, 1903 (source 1); Ukers writes his first name Sartori (source 2). The patent already describes the problem that would occupy the whole century: keeping the aroma. Kato presses the ground coffee to remove the fats, which make the product go rancid, distills the volatile oil separately, reduces the extract to a hard mass, then mixes the oil back into part of the powder, dried below 40 °F, or about 4 °C, “to keep the aroma,” before bringing everything together into granules or tablets (source 1).
Ukers tells what followed. Kato had come to Chicago around 1899 with a soluble tea that had not sold; his coffee was sold to the public at the Pan-American Exposition of 1901, and his first big order left with the Ziegler arctic expedition (source 2). George Washington, born in Belgium to English parents and settled in Guatemala, invented around 1906 another instant coffee, ready in 1909 and sold from 1910 by his Brooklyn company; his process remained secret and was never patented (source 2).
The First World War did the rest. Instant coffee entered the American reserve ration; a month before the armistice, the New York depot learned it would need 42,500 pounds a day from 1919, and a quartermaster official judged that mustard gas had made it one of the army's most important subsistence items (source 2). In 1922, Ukers describes the typical factory: a battery of three to seven percolators, an evaporator and a vacuum drum dryer that turns out 25 to 500 pounds of powder an hour (source 2). The chemist Charles Trigg concludes there that an instant coffee capable of equaling a freshly made coffee remains to be invented (source 2).
The modern process, Nestlé's spray-drying in 1938 and then freeze-drying in the 1960s, is told and sourced in the plate on caffeine and instant coffee, which also details its manufacture.
The motion
A spoonful of powder or granules, water, a stir. Ukers already notes that instant coffee dissolves in hot water as in cold (source 2). There is no grind, filter or grounds: extraction took place at the factory, at temperatures and yields that no kitchen reaches.
The moment that matters is the first. When hot water touches the powder, a puff of aromas escapes in the very first seconds, then the intensity drops; the Swiss and Brazilian team that measured it speaks of an “aroma explosion” (source 3). The nose therefore does well to be above the cup at that moment.
The settings
- Grindnot applicable: powder or granules already extracted
- Dosenot documented in the sources read; each manufacturer gives its own
- Brew rationot documented in the sources read
- Temperaturehot or cold water (source 2)
- Timeimmediate dissolution; most of the aromas are released in the first seconds (source 3)
- Pressurenot applicable
What it has going for it
- Ukers already gave its three merits in 1922: speed of preparation, absence of grounds and consistency from one cup to the next (source 2).
- It is prepared without fire or utensil, which made it a soldier's ration as early as the First World War (source 2).
- It keeps: Kato had removed the fats from his extract precisely so that it would not go rancid during transport and storage (source 1).
What is held against it
- Aroma has been the weak point from the start: in 1922, all the instant coffees on the market lacked aroma and the most delicate flavors, by Ukers's own admission (source 2).
- What aroma remains leaves all at once on reconstitution, then the cup fades quickly (source 3).
- The powder can be adulterated without the eye seeing it: products sold as pure were not, and a study sets thresholds for sugars, 2.46% total glucose and 0.45% total xylose, beyond which an instant coffee must be held to be adulterated (source 4).
- Instant coffee concentrates compounds formed by heat: in a French study of twelve instant coffees, none exceeded the European indicative value for acrylamide, but the authors count these products among the possible major contributors to these compounds for those who drink it every day (source 5).
What it gives in the cup
The cup of instant coffee begins with the nose: the aroma is released in a puff on contact with hot water, each molecule at its own pace according to its volatility and solubility, then the odor above the cup declines (source 3). It is the reverse of a filter, whose aroma renews itself as long as the cup is hot.
The foam that covers some instant coffees does not come from the coffee itself: it is obtained by gasifying the product at manufacture, and a gasified spray-dried powder releases poorly water-soluble aromas faster (source 6). Under the foam, the drink keeps the taste of an extraction pushed far beyond that of a kitchen, whose origin the plate on instant coffee explains, the very hot water of industrial columns.
Anecdotes
- The trade name “Washington's Coffee Extract” was abandoned because it displeased, Ukers writes, certain authorities in the federal capital (source 2).
The sources for this sheet
- Satori Kato, US patent 735,777, “Coffee concentrate and process of making same,” assigned to the Kato Coffee Company, Chicago, filed April 1901, granted August 11, 1903 · online · primary
- William H. Ukers, All About Coffee, New York, 1922, ch. XVII (Charles W. Trigg, chemistry of infusion and of instant coffee), ch. XXV (manufacture of dried extracts) and ch. XXXI (history of instant coffee) · online · secondary
- R. C. Zanin et al., “Novel experimental approach to study aroma release upon reconstitution of instant coffee products,” Food Chemistry, 317, 126455, 2020 · online · primary · reading: article abstract
- P. Girard et al., “Carbohydrate specification limits for the authenticity assessment of soluble (instant) coffee: statistical approach,” Journal of AOAC International, 89 (4), 999-1003, 2006 · online · primary · reading: article abstract
- G. Loaëc et al., “Acrylamide, 5-hydroxymethylfurfural and Nε-carboxymethyl-lysine in coffee substitutes and instant coffees,” Food Additives and Contaminants, part A, 31 (4), 593-604, 2014 · online · primary · reading: article abstract
- S. P. Ishwarya and P. Nisha, “Unraveling the science of coffee foam: a comprehensive review,” Critical Reviews in Food Science and Nutrition, 61 (10), 1704-1724, 2021 · online · secondary · reading: article abstract