Ukers himself poses the problem without resolving it. On chicory, he notes that “in Europe, chicory is not considered an adulteration: it is an addition, or a modifier,” that he himself ended up acquiring a taste for it in France, “but it is not coffee,” and above all that so many people have acquired this taste that he doubts they would appreciate a real cup of coffee if they met one. It is, in one sentence of 1922, the recognition that a way of drinking is not a preference but an apprenticeship.

Ukers 1922, ch. XXXV, p. 655-694

The mechanism is described elsewhere, and it comes down to one sentence: taste is built by repeated exposure.

Bourdieu formalized it in La Distinction, in 1979, under the name of habitus. It is the set of dispositions acquired through social position and repetition, and they are so thoroughly embodied that they present themselves as natural facts. One does not experience a learned preference as a learned preference: one experiences it as a taste one has.

Physiology adds one more reason. Olfactory signals reach the amygdala, a structure of emotional memory, without first passing through conscious examination. A smell is thus recognized and judged before it is thought.

A figure circulates, ten to fifteen exposures to accept a new flavor. It calls for caution, because it comes from studies on young children, and nothing says it transposes as it is to adults.

What is established is simpler: acceptance of an unknown flavor is won by repetition and not by explanation. In other words, nobody is convinced to like a coffee. They are made to drink it several times.

Bourdieu, La Distinction (1979); syntheses on food acceptance in young children; discussion and caveats in LC ch. 10

Applied to 19th-century Europe, this mechanism sheds light on Ukers's descriptions. What was drunk was a very dark liquid, obtained from a powder that colored water instantly, often thick and frankly bitter, because roasted chicory, barley and rye each contributed their own bitterness. The dark, the thick and the frank bitterness are exactly the three traits that many drinkers still call today “a real coffee,” and the hypothesis is that a part of this reference was built by a century in which coffee was not entirely coffee.

The level of proof must be stated: there is no sensory measurement from the period, and the share of fraud cannot be separated from damp transport, heavy roasts and the habit of reboiling. See the plate Adulteration.

LC ch. 10, from Walsh and the analysis records of the 19th century; on chicory in Europe, Ukers 1922, ch. XXXV; on climatic regularity, professional training document, L'Histoire du café