Research note 031 — 2026-09-04
When Cacao Was a Bitter Drink
Almost no one today doubts that chocolate is sweet. But cacao itself, as a material, was not paired with sweetness from the start. Colonial-era dictionaries recorded the unsweetened cacao drink as "very bitter," and material on the chemistry side has identified several of the compounds mainly responsible for roasted cacao nibs' bitterness. And there are also ways of eating cacao, such as mole and tejate, that keep it unsweetened to this day. This note works through three bodies of material in turn — dictionaries, chemistry, and standards — to check where the relationship between cacao and bitterness has been discussed, and where it stopped being discussed.
On this page (8 sections)
What this page establishes
- One etymological study finds that colonial-era dictionaries record the unsweetened cacao drink as very bitter.
- Theobromine and caffeine are repeatedly reported as the compounds behind roasted cacao nibs' bitterness, but one study also found that raising the roasting temperature lowered perceived bitterness.
- Alkalization is described in the material as an industrial process that reduces bitterness, but a specific sensory-score figure for that reduction has not yet been confirmed.
- US federal regulations give the name "bittersweet" only to the chocolate-liquor-35%-or-more category, not to the milk chocolate category.
1. What the Bitter Water Was Called
A study discussing the etymology of the word chocolate cites the description in the Real Academia Española's dictionary and analyzes the word form xócoatl as a compound of xócoc (bitter, sour) and atl (water). It also notes that, although this differs in lineage from cacáhuatl (cacao water), another word for cacao, the two were used together for the same group of beverages.
Scope: The paper organizes descriptions from colonial-era dictionaries (RAE 2001, Robelo 1904, Diccionario de americanismos 2011)
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dish-xocoatl —has_name_etymology→ "xócoatl is analyzed as a compound of xócoc (sour/bitter) and atl (water), meaning "bitter water, sour water." It is a different lineage of word from cacáhuatl (cacao water), which also refers to cacao, but the two were used together for the same group of beverages."In support of this analysis, the same study also quotes the colonial-era dictionaries themselves. Robelo's Diccionario de aztequismos describes the cacao drink mixed with water and without added sweetness as muy amargo (in translation: "very bitter"), and Molina's vocabulary explains why a headword for the unsweetened cacao drink is nearly absent from other sources with the reasoningno se bebía mucho, era muy amargo (in translation: "it was not drunk much — it was very bitter").
Scope: Colonial-era record: el cacao con agua y sin dulce es muy amargo (in translation: "cacao with water and without sweetness is very bitter") (Robelo 1904). Molina's Vocabulario (1555/1571) explains the reason the word cacao solo (an unsweetened cacao drink) does not appear in other sources as no se bebía mucho, era muy amargo (in translation: "it was not drunk much — it was very bitter").
Note: A historical, discursive record based on Spanish-language documents from the 16th to the 20th century, not a modern sensory measurement.
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dish-xocoatl —has_sensory_attribute→ sensation-bitterThat the unsweetened drink was the exception can also be read from the other headwords preserved in Molina's vocabulary. It lists, as separate words, several variants — a cacao drink with chile added, a cacao drink with dried flowers added, and more — with the unsweetened version recorded merely as one option among them.
Scope: A list of headwords from a 16th-century Nahuatl-Spanish dictionary
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dish-xocoatl —has_variant→ "Molina's Vocabulario (1555/1571) records, as separate words, chillo cacauatl / chilcacauatl (a cacao drink with chile added), xochiayo cacauatl (a cacao drink with dried flowers added), atlanelollo cacauatl (an unsweetened, cacao-only drink), and others."As for the preparation itself, the dictionary headwords are argued to show a method of combining ground cacao beans with water or atole (corn gruel) and finishing by whipping it into foam.
Scope: A method of preparation combining ground cacao beans with water or atole (corn gruel) and finishing by whipping it into foam
Note: Connects the existing cacao line (ingredient-roasted-cocoa-nibs, etc.) to the Mesoamerican beverage context.
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dish-xocoatl —is_prepared_with→ ingredient-roasted-cocoa-nibsThe same etymological study also offers a historical framing in its conclusion, arguing that the Olmecs invented the process of heating, separating, and recombining the bitter fruit, turning a bitter fruit into a nutritious beverage. It should be noted that this is not the presentation of primary archaeological data, but a historical summary offered within an etymological paper.
Scope: A historical narrative in the conclusion of an etymological study
Note: Recorded as the historical framing of an etymological paper, not as archaeological verification.
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dish-xocoatl —has_historical_origin_narrative→ "The paper frames it by saying that "the Olmecs invented the process (of heating, separating, and recombining the bitter fruit) and transformed the bitter fruit into a nutritious beverage," tracing this lineage from the word forms cacau/cacáhoatl."2. The Bitterness Inside the Bean
When the dictionaries wrote that it was bitter, what carried that taste? A study that reconstructed roasted cacao nibs in a water-based system and repeatedly tested by removing components one at a time reported that theobromine and caffeine remained the primary sensory-contributing compounds throughout.
Scope: Water-based reconstruction of roasted cacao nibs and human omission testing
Note: Specific to the roasted-nib material studied and the water-based model.
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ingredient-roasted-cocoa-nibs —has_key_bitter_organoleptics→ "Theobromine and caffeine"That the water-based reconstruction was able to reproduce the taste profile of the roasted-nib suspension is itself recorded as a finding of the same body of research.
Scope: Roasted cacao nibs and taste reconstruction in a water-based system
Note: The finished chocolate requires a separate matrix and process record. / 2026-08-31: Calibrated down from established to supported because the supporting evidence does not derive from a full-text check. May be re-upgraded once the full text is checked.
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ingredient-roasted-cocoa-nibs —has_sensory_attribute→ sensation-bitterA study taking a different approach, sensory-guided fractionation, lists epicatechin, catechin, and several procyanidins, in addition to theobromine and caffeine, as key compounds contributing to roasted cacao's bitterness and astringent mouthfeel. This material, however, treats bitterness and astringency together for this group of compounds, and does not separate the two qualities out compound by compound.
Scope: Roasted cacao nibs, sensory-guided fractionation
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ingredient-roasted-cocoa-nibs —has_bitter_and_astringent_contributors→ "In addition to theobromine and caffeine: epicatechin, catechin, procyanidin B-2, procyanidin B-5, procyanidin C-1, [epicatechin-(4beta->8)]3-epicatechin, and [epicatechin-(4beta->8)]4-epicatechin"A separate group of compounds carrying astringency alone has also been identified. A report finds that a family of N-phenylpropenoyl amino acid amides — including clovamide, previously reported for a different property — has been newly identified as key astringent compounds in roasted cacao. Bitterness and astringency coexist within the same bean, but they are not carried by the same compounds.
Scope: Roasted cacao nibs, taste dilution analysis and half-tongue threshold testing
Note: These compounds are reported as contributing to astringency, not bitterness. Cacao's astringency cannot be reduced to flavan-3-ols alone.
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ingredient-roasted-cocoa-nibs —has_key_astringent_compounds→ "N-phenylpropenoyl amino acid amides, including clovamide, deoxyclovamide, and (-)-N-[3',4'-dihydroxy-(E)-cinnamoyl]-L-tyrosine, along with glycopyranosides of quercetin, naringenin, luteolin, and apigenin"3. Which Way Do Roasting and Fermentation Move Bitterness?
Whether bitter compounds exist inside the bean and how bitter the final product actually tastes are separate questions. A consumer-panel test on unsweetened 100% chocolate reported that perceived bitterness actually fell as the roasting temperature rose. Turning up the heat does not automatically mean stronger bitterness.
Scope: 27 roasting treatments across 3 origins, 145 chocolate consumers, gLMS
Note: The direction is the reverse of the intuition that 「焙煎温度が高いほど苦くなる」 (in translation: "the higher the roasting temperature, the more bitter it becomes"). No p-value is given for this effect size.
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process-cocoa-roasting —reduces→ sensation-bitterFermentation, too, does not move the amount of bitterness-related compounds in only one direction. A test that fermented several cacao genotypes under temperature control reported a trajectory in which theobromine and caffeine concentrations fell during the first half of fermentation and rose during the second half. The authors also state that controlled fermentation does not fully reproduce natural fermentation.
Scope: 3 cacao genotypes (CCN 51, ICS 95, TCS 01), 3 temperature-controlled fermentation profiles
Note: A non-monotonic trajectory. Only 3 genotypes were tested, and temperature-controlled fermentation is a different thing from natural fermentation.
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process-cocoa-fermentation —can_change→ "Theobromine and caffeine concentrations decreased through day 5 and increased by day 6, while catechin rose through day 5 and decreased by day 6"Even in processed cocoa powder, the lineup of compounds carrying bitterness is not simply that of the roasted cacao nib. An analysis using the Dose-Over-Threshold measure reports that several compounds, including epicatechin, theobromine, and caffeine, contribute significantly to cocoa powder's bitterness, while a partly different set of compounds plays the key role in astringency.
Scope: Cocoa powder before and after microwave-assisted alkalization
Note: Methylxanthines appear in the same DOT set alongside 4 kinds of phenolics, and are not the sole bitterness driver in this material.
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ingredient-cocoa-powder —has_key_bitter_organoleptics→ "Epicatechin, (-)-epigallocatechin gallate, luteolin, protocatechuic acid, theobromine, caffeine (dose-over-threshold above 1)"And alkalization — the industrial process of alkalizing, also called the Dutch process — is positioned as one of the techniques for artificially reducing this bitterness. One study describes this treatment as an important step in cocoa processing for reducing bitterness, increasing solubility, and developing color, while also reporting, in a sponge-cake test that applied different treatment conditions, that consumers' overall rating itself did not change significantly with the treatment condition.
Scope: A test applying commercial cocoa powder, with varied alkalization treatment conditions, to sponge cake
Note: A sensory-score figure for bitterness itself has not been confirmed within the range of abstracts and secondary summaries reached so far. It is shown here by combining the description positioning it as a process that reduces bitterness with the cake's sensory-evaluation data. Reaching the full text was not completed this time (the publisher's site sits behind a paywall).
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ingredient-cocoa-powder —can_be_debittered_by→ "Alkalization (alkalizing / the Dutch process). An industrial process that treats cocoa with alkalizing agents such as potassium carbonate, sodium carbonate, and sodium hydroxide, raising the pH from natural cocoa's acidic range to a neutral-to-alkaline range. Puchol-Miquel et al. (2021), after positioning this treatment as "an important step in cocoa processing for reducing bitterness, increasing solubility, and developing color," applied commercial cocoa powders with varying types and degrees of alkalization to sponge cake, and reported that while differences in treatment conditions affected the batter's physical properties and the cake's color and texture, consumers' overall rating itself did not change significantly with the treatment condition."4. Ways of Eating Cacao Unsweetened
One way of keeping cacao unsweetened down to the present is tejate. This beverage, served with a foam raised from corn and cacao as its main ingredients, is recorded — in an analysis of samples collected from Oaxacan communities, urban markets, and immigrant vendors in the United States — as a source of methylxanthines, energy, lipids, and minerals.
Scope: Analysis of samples collected from 3 communities in the Central Valleys of Oaxaca, urban markets, and immigrant vendors in the United States
Note: The abstract does not give individual quantitative values for methylxanthines. Connection to cacao-related entities (compound-theobromine, etc.) is left for after a future full-text check.
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dish-tejate —contains→ "Made mainly from corn and cacao and served with a raised foam. A source of methylxanthines, energy, lipids, K, and Fe"The same study also touches on how foam-topped cacao-and-corn beverages have a long lineage in Mesoamerica, and positions tejate as both a ceremonial beverage in the Zapotec region and one that has held a staple-food-like place supporting periods of intense fieldwork.
Scope: The Central Valleys of Oaxaca, Mexico
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dish-tejate —has_cultural_role_of→ "A ceremonial beverage in the Zapotec region that has also held a staple-food-like place during periods of intense fieldwork. Part of a lineage of foam-topped cacao-and-corn beverages with a long history in Mesoamerica"Another way it has been kept is through mole. A source discussing a chile from Oaxaca positions it as an "indispensable" ingredient in black mole negro.
Scope: A chile from the Cañada region of Oaxaca, regarded as essential to mole negro
Note: Connects, for the first time, a sourced composition claim to the existing candidate entity dish-mole-negro.
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dish-mole-negro —includes→ ingredient-chilhuacle-chileA measured recipe appearing in a study on quality control for mole poblano lists chocolate tablets as an ingredient alongside several kinds of chiles, almonds, raisins, bread, and spices.
Scope: Example measured recipe: uses 400g chile ancho, 100g chile pasilla, along with almonds, peanuts, raisins, bread, tortillas, spices, and more, plus 2 tablets of chocolate (tablillas)
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dish-mole-poblano —includes→ ingredient-roasted-cocoa-nibsThe same study also gives a concrete description of mole's preparation process: each ingredient — vegetables, chiles, seeds, and the like — is pan-fried over low heat one kind at a time, and the heating stops once it takes on a light golden color. It is worth noting that this heating stops short of actually browning or charring the ingredient.
Scope: A standard process description in a study on quality control for mole poblano (based on Gironella 1994)
Note: Included only as a process description, as a candidate connection to note020's four-quadrant "technique of addition." No sensory claim is made about the threshold between browning and charring.
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process-mole-chile-toasting —is_documented_using→ "The paper's process description shows that ingredients such as vegetables, chiles, and seeds are pan-fried (freír) over low heat one kind at a time, and heating is stopped once they take on a light golden color (dorado suave)."Looked at from the cacao mole sauce side, Mexico's national food standard defines "chocolate" as a product mixing two or more of cacao paste, cacao butter, and cocoa, and includes within it the categoriesamargo (bitter) and semi-amargo (semi-bitter).
Scope: Mexico's national food standard
Note: Connects a regulatory definition to the existing candidate entity seasoning-cacao-mole.
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seasoning-cacao-mole —is_defined_in_regulation_as→ "Mexican standard NOM-186-SSA1/SCFI-2002 defines "chocolate (including amargo/semi-amargo)" as a homogeneous product made by mixing 2 or more of cacao paste, cacao butter, and cocoa, with sugars and other optional ingredients added."5. "Bitter" in the Standard, "Bitterness" on the Shelf
Even as the vocabulary from the age when cacao was an unsweetened drink has disappeared, the word "bitter" still survives inside the naming rules forchocolate. US federal regulations specify that sweet chocolate containing 35% or more chocolate liquor by weight is to be named "semisweet chocolate" or "bittersweet chocolate."
Scope: United States, 21 CFR 163.123
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ingredient-dark-chocolate —is_defined_in_regulation_as→ "Sweet chocolate containing 35% or more chocolate liquor by weight is designated by the name "semisweet chocolate" or "bittersweet chocolate""Yet within that same regulatory system, the provision definingmilk chocolate uses no word corresponding to "bitter." It is defined only as a food containing 10% or more chocolate liquor and 12% or more milk solids by weight.
Scope: US 21 CFR 163.130
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ingredient-milk-chocolate —is_defined_in_regulation_as→ "Defined as a food containing chocolate liquor at 10% or more and milk solids at 12% or more by weight, with no word corresponding to "bitter" used in the provision"Setting the two provisions side by side shows that whether the standard grants the name "bitter" is not uniform even within the single category of chocolate.
Scope: Naming of chocolate products under United States federal regulation (21 CFR Part 163)
Note: Records a naming pattern in the standard: a name including "bitter" (semisweet / bittersweet chocolate) is given only to the 35%-or-more chocolate-liquor category, while no such name is given to the 10%-or-more milk chocolate category. One piece of evidence for the H10 reformulation (whether a product's positioning is mass-market or differentiated).
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ingredient-dark-chocolate —differs_from→ ingredient-milk-chocolateOn the side of differentiated craft chocolate, this bitterness instead becomes a selling point. A Temporal Dominance of Sensations (TDS) evaluation of single-origin dark chocolate reported that the relationship in which bitterness dominance strengthens as cacao percentage rises varied in strength by origin and brand. A higher cacao percentage does not translate directly into stronger bitterness.
Scope: TDS panel evaluation of 5 origin (66.8-80.1% cc) and 6 non-origin (54.5-80.0% cc) dark chocolates
Note: This is not a source claiming the simple, monotonic relationship that "the higher the cacao percentage, the more bitter it always tastes." Its main point is an assertion of asymmetry: that for origin chocolate, factors arising from growing region and cultivation conditions govern bitterness dominance more than the labeled cacao percentage does.
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ingredient-dark-chocolate —has_bitterness_correlated_with→ "Cacao percentage (shown as %). Oberrauter et al. (2018) used the TDS (Temporal Dominance of Sensations) method to compare 5 single-origin dark chocolates (cacao percentage 66.8-80.1%) with 6 non-origin (blended) chocolates (cacao percentage 54.5-80.0%). In the non-origin group, bitterness dominance rate (DR%) rose clearly as cacao percentage increased, whereas in the origin group bitterness remained the dominant attribute regardless of cacao percentage for about 75% of the tasting time, and the relationship with cacao percentage was described as "relatively small or barely observed." In other words, the strength of the relationship between cacao percentage and bitterness dominance was asymmetric, differing by the bean's origin and brand."Even in an official description of a differentiated brand, bitterness is not hidden — it is brought to the front. One couverture maker's explanation of its tasting method describes rolling the chocolate in the mouth, sensing sourness first, and then, after waiting a little longer, being able to sense bitterness.
Scope: An explanation of Valrhona's (a differentiated brand, bean-to-bar/couverture) official tasting method
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ingredient-dark-chocolate —has_defining_sensory_theme→ "After rolling the chocolate in the mouth, sourness is sensed first, and bitterness can be sensed after waiting a little longer"The same maker's description of its high-cacao-percentage product positions that bitterness with phrases like 「深い苦味と香りの頂点」 (in translation: "the peak of deep bitterness and aroma") and 「力強くもエレガントな苦さの極み」 (in translation: "the height of a bitterness both powerful and elegant"). The taste that a colonial-era dictionary described as too bitter to leave much trace in the record is here named as a priced individuality.
Scope: Product description for Valrhona Guanaja 70% (a differentiated brand, couverture, 70% cacao content)
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ingredient-dark-chocolate —is_presented_as→ "The pinnacle of deep bitterness and aroma. The height of a bitterness that is both powerful and elegant, with a lasting aroma"What is not known
The analysis that xócoatl's word-formation means "bitter water" is a separate matter from the etymology of the word chocolate itself. The etymological study quoted here offers its own theory about chocolate's origin, and the field remains contested. Here, only the part concerning the word-formation of xócoatl/cacáhuatl has been adopted.
Also, whether roasted cacao nibs' sensory attributes are consistently preserved all the way through to the finished chocolate has not received a uniform answer within the material confirmed here. Results from water-based models or laboratory nibs cannot be applied directly to commercial chocolate as they stand. For mole and tejate too, regional variation, variation between vendors, and variation between recipes are recorded in the material itself; there is no single correct way to make them.
Frequently asked
Was cacao originally not a sweet drink?
Colonial-era dictionaries record the cacao drink mixed with water and without added sweetness as muy amargo (in translation: "very bitter"). One etymological study, as one of several theories about the origin of the word chocolate, introduces multiple dictionaries' analysis of the word xócoatl as a compound of xócoc (bitter, sour) and atl (water). The same material argues that the reason a headword for the unsweetened cacao drink barely appears in other sources is that it was not drunk much — it was very bitter. This, however, is a description that includes the dictionary authors' own interpretation, and is not itself a primary record of anyone actually tasting the drink.
Does chocolate get more bitter the harder it is roasted?
A consumer-panel test on unsweetened 100% chocolate reports that raising the roasting temperature by 1 standard deviation (42 degrees) actually lowered the strength of bitterness. The same study also states that the decrease in bitterness and astringency correlated with an increase in consumer acceptability. Meanwhile, a separate study that showed roasted cacao nibs themselves contain compounds related to bitterness did not compare different roasting temperatures, and does not report a relationship between roasting conditions and perceived bitterness. How the roasting process moves bitterness-related compounds, and how the bitterness actually perceived moves, are set out here as separate questions.
Related:xócoatl / tejate / mole poblano / mole negro / roasted cacao nibs / cacao roasting / cacao fermentation / cocoa powder / dark chocolate / milk chocolate
Related research notes:Can Cooking Create Bitterness? / Standards Certify Bitterness, the Shelf Chooses It
Source ledger: the source ledger
How to cite this page
Aoki, M. (NIGAMI LAB) (2026). When Cacao Was a Bitter Drink. https://nigamilab.com/en/notes/when-cacao-was-bitter/
Each claim card has a stable anchor (#clm-…). The dataset is CC BY 4.0; see the data page. Dataset DOI: 10.5281/zenodo.22739101