Topic hub — 2026-10-21
Do beers with higher IBU taste more bitter?
The IBU (international bitterness units) on a beer label is often read as "the bigger, the more bitter". What do studies say that set IBU or bitter-compound levels against the bitterness people perceived? This page lines up the included studies together with their conditions: the beers (commercial or trial brews), how bitter compounds were measured, and who rated them on what scale. It then separates what was established within one experiment, what differences between studies might explain, and what this comparison alone cannot separate.
On this page (10 sections)
- What this page establishes
- What the included studies allow us to say
- Bitterness ratings at a glance
- Conditions and results, study by study
- What was established within an experiment
- Candidate explanations for the differences
- What is not known — what this comparison alone cannot separate
- How studies and rows were counted
- What we looked at
- Read in the encyclopedia
What this page establishes
- That commercial beers with more bitter compounds tend to score as more bitter, but what was measured was bitter compounds (iso-alpha acids), not IBU.
- That one study of commercial beers found bitterness units (BU) explained bitterness scores best, but in the sources searched no full paper reported the correlation value in its text.
- That beers with the same IBU can differ in bitterness and in their compounds, and in one pair of the same variety the higher-IBU beer had the lower mean bitterness.
- That alcohol, sweetness and beer style may contribute to the gap, but they cannot be separated from the comparisons included here.
What the included studies allow us to say
- Commercial beers with more bitter compounds do tend to score as more bitter: across 250 beers the rank correlation of iso-alpha acids with bitterness was 0.68, and across 16 lagers a prediction from 6 compounds reached 0.92 (the latter not yet verified). But both measured iso-alpha acids, not IBU. In one study of 10 commercial beers bitterness units (BU) explained bitterness scores best, but the text gives no correlation value or beer-by-beer correspondence. [rows: Schreurs 2024 iso-alpha acids and bitterness; Techakriengkrai 2004 predicted from 6 compounds; Ozaki & Wanikawa 2008 regression of bitterness]
- A higher IBU does not always mean more bitter: in trial beers, 2 brews with the same reported mean BU of 22 had intensities of 2.4 and 1.2, and of 2 brews of the same variety and boil at BU 106 and 118, the lower-BU one had the higher mean (4.9 vs 3.4). Brewing with aged hops kept BU nearly the same (47.5 and 49.9) while iso-alpha acids fell from 39.9 to 2.2 mg/L. IBU (BU) is a gauge measured by the absorbance of an extract, not the bitterness people perceive. [rows: Rutnik 2022 same BU; Rutnik 2023 same variety and boil, ageing only; Kishimoto 2021 aged hops]
Bitterness ratings at a glance
Human bitterness ratings and bitter-compound levels; for correlation rows, "Comparison" is "not applicable". Values for "Sample compared" and "Comparison" are as reported in the tables or figures (values read from figures are marked as estimates). "Direction" shows which sample was more bitter; gaps the paper does not treat as a difference are shown as "about the same". Select a study name to jump to its detailed table.
Results in which people rated bitterness only. Where each value comes from (a table or a reading from a figure) is shown in its row; scales and methods differ between studies, so compare within a row, not across rows.
| Study | Comparison and condition | Measured as | Sample compared | Comparison | Direction / test |
|---|---|---|---|---|---|
| Techakriengkrai 2004 | predicted from 6 compounds Bitterness scores of 16 lagers against 6 compounds including iso-alpha acids | correlation (scores of 14 people) | predicted vs measured 0.92 | 3 single iso-alpha acids 0.54, 0.74, 0.67 | Sample compared higher No test reported |
| Schreurs 2024 | iso-alpha acids and bitterness Iso-alpha acids against bitterness scores in 250 beers (22 styles) | rank correlation (standardised scores from a panel of 16) | ρ = 0.68 | not applicable (correlation) | Sample compared higher No test reported |
| Ozaki & Wanikawa 2008 | regression of bitterness Regression (PLS) of bitterness scores of 10 beers on water-soluble components | rank of contribution in the regression (7 people) | bitterness units (BU) the largest contributor | not given (values only in a figure) | Direction not given No test reported |
| Rutnik 2022 | same BU 2 beers with the same reported mean BU of 22: Aurora hops (ageing index 0.3) vs Celeia (0.6) | bitterness intensity 1–5, mean ± SD (10 people) | 2.4 ± 0.39 | 1.2 ± 0.24 | Sample compared more bitter No test reported |
| Rutnik 2023 | boiling time Celeia boiled 45 min (ageing index 0.5) vs 5 min (0.3) | bitterness intensity 0–5, mean ± SD (10 people) | 2.4 ± 0.2 (BU 51, iso-alpha acids 50.2 mg/L) | 1.1 ± 0.3 (BU 45, iso-alpha acids 18.0 mg/L) | Sample compared more bitter No test reported |
| Ramos-Parra 2024 | non-alcoholic Non-alcoholic pilsner (IBU 15.5) vs pilsner (IBU 16.8) | share of just-about-right answers (50 people) | 42% "not bitter enough" | 54% "just about right" | Direction not given No test reported |
| Rutnik 2022 | same variety, ageing only Aurora at ageing index 0.7 vs 0.5 (BU 34 and 39) | bitterness intensity 1–5, mean ± SD (10 people) | 4.3 ± 0.26 (BU 34) | 4.0 ± 0.37 (BU 39) | About the same Tested, not significant |
| Rutnik 2023 | same variety and boil, ageing only Styrian Wolf boiled 90 min at ageing index 0.3 vs 0.5 (BU 106 and 118) | bitterness intensity 0–5, mean ± SD (10 people) | 4.9 ± 0.2 (BU 106) | 3.4 ± 0.3 (BU 118) | Sample compared more bitter No test reported |
Conditions and results, study by study
For each study, the conditions for the beers, how bitter compounds were measured and the rating, and the results. Each row is one study × one measured result, so different comparisons in the same study are separate rows. Under each row we give where it is in the paper and whether it can be used to judge whether more IBU or bitter compounds means people perceive more bitterness, with the reason. Nothing is left blank: "not given", "not read" and "not applicable" are kept apart.
Techakriengkrai 2004 sensory only
Relationships of Sensory Bitterness in Lager Beers to Iso-alpha-Acid Contents. Journal of the Institute of Brewing 110(1):51-56 — doi:10.1002/j.2050-0416.2004.tb00180.x
- How deeply checked
- Checked in full text — The reader read 6 pages of text on the publisher viewer (Tables I and II, pp. 52–54); the verifier could not retrieve the source (only a challenge page), so values for this study rest on a single reading Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- 16 commercial lagers bought in the UK (3.0–5.5% alcohol)
- Processing and cooking
- HPLC of 3 iso-alpha acids and 3 tetrahydro-iso-alpha acids (total iso-alpha acids 2.1–101.1 ppm); IBU not measured
- How it was served or eaten
- Tasted as sold; sugar, pH and carbonation not given
- Who rated, on what scale
- 18–19 trained students and staff; rank-rating (0–100), 2 replicates; 4 panellists with extreme scores were excluded for the prediction model, leaving 14; ANOVA and Duncan test
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Bitterness intensity (sensory) | predicted from 6 compounds Bitterness scores of 16 lagers against 6 compounds including iso-alpha acids | predicted vs measured 0.92 | 3 single iso-alpha acids 0.54, 0.74, 0.67 | correlation (scores of 14 people) | Sample compared higher No test reported |
| 0.92 is the cross-validated value of a regression (PLS) on 6 compounds, after excluding 4 panellists with extreme scores; IBU was not measured; the verifier could not check this study's values against the source Where: Table II, p. 54 For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Commercial beers with human bitterness and compounds, but iso-alpha acids rather than IBU; the value is a regression fit, with 4 panellists excluded | |||||
Schreurs 2024 sensory only
Predicting and improving complex beer flavor through machine learning. Nature Communications 15:2368 — doi:10.1038/s41467-024-46346-0
- How deeply checked
- Checked in full text — Full text via Europe PMC (main text); supplementary data and the contents of Fig. 2 not viewed Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- 250 commercial beers sold in Belgium (22 styles)
- Processing and cooking
- 226 measurements; iso-alpha acids by an automated photometric analyser; the main text reports no IBU measurement (supplementary data not viewed)
- How it was served or eaten
- Tasted at 12–16 °C
- Who rated, on what scale
- A trained panel of 16 (selected from 30; not everyone attended every session); 50 attributes on 7 points, standardised per panellist; 5–12 beers of one style per session
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Bitterness intensity (sensory) | iso-alpha acids and bitterness Iso-alpha acids against bitterness scores in 250 beers (22 styles) | ρ = 0.68 | not applicable (correlation) | rank correlation (standardised scores from a panel of 16) | Sample compared higher No test reported |
| A correlation across styles; correlations within a style are not shown; sweetness and bitterness ρ = −0.48 Where: Text (Fig. 2 description) For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Large (250 beers), but iso-alpha acids rather than IBU, and a correlation across styles | |||||
Rutnik 2022 sensory only
Impact of Hop Freshness on Dry Hopped Beer Quality. Foods 11(9):1310 — doi:10.3390/foods11091310
- How deeply checked
- Checked in full text — Full text via Europe PMC (Tables 5 and 6, Section 3.3) Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- 15 trial ales (3 hop varieties × 5 levels of hop ageing)
- Processing and cooking
- Dry-hopped after fermentation with 10 g/L hops at 20 °C for 5 days; BU (absorbance at 275 nm of an isooctane extract) 21–45; iso-alpha acids low at 1.95 mg/L or less
- How it was served or eaten
- Tasted at 10 °C; no alcohol, residual sugar or pH values are reported
- Who rated, on what scale
- 10 trained panellists; bitterness intensity and quality on 1–5 in 0.5 steps; one-way ANOVA and Tukey test (5% level); values are means ± SD
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Bitterness intensity (sensory) | same BU 2 beers with the same reported mean BU of 22: Aurora hops (ageing index 0.3) vs Celeia (0.6) | 2.4 ± 0.39 | 1.2 ± 0.24 | bitterness intensity 1–5, mean ± SD (10 people) | Sample compared more bitter No test reported |
| An example of different intensity at the same BU; the test for this pair was not read; iso-alpha acids were low in these dry-hopped beers Where: Tables 5 and 6 For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Shows different intensity at the same BU, but in trial beers dry-hopped at 10 g/L with little iso-alpha acid | |||||
| Bitterness intensity (sensory) | same variety, ageing only Aurora at ageing index 0.7 vs 0.5 (BU 34 and 39) | 4.3 ± 0.26 (BU 34) | 4.0 ± 0.37 (BU 39) | bitterness intensity 1–5, mean ± SD (10 people) | About the same Tested, not significant |
| The lower-BU beer had a slightly higher mean intensity, but the text states the intensity difference was not significant; no significant difference does not mean the same Where: Tables 5 and 6, Section 3.3 For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Same variety with only ageing varied; intensity did not fall as BU fell, but the gap was not significant; trial beers low in iso-alpha acids | |||||
Rutnik 2023 sensory only
The Impact of Hop Freshness on Kettle-Hopped Beers. Foods 12(23):4353 — doi:10.3390/foods12234353
- How deeply checked
- Checked in full text — Full text via Europe PMC (Tables 7 and 8, Section 3.3); the methods say 45 beers were rated, but Table 8 lists 30 Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- 45 trial beers (3 hop varieties × 5 ageing levels × boiling 5, 45 or 90 min); bitterness sensory on 30 beers of 2 varieties (1 excluded as too bitter; aroma sensory on all 45)
- Processing and cooking
- Hops boiled in wort; BU 28–122 and iso-alpha acids 10–174 mg/L across all 45 beers, and BU 28–118 and iso-alpha acids 10–148 mg/L across the 30 with bitterness sensory
- How it was served or eaten
- Tasted at 10 °C; no alcohol, sugar or pH values are reported
- Who rated, on what scale
- 10 trained panellists; bitterness intensity and quality on 0–5 in 0.5 steps; ANOVA and Tukey test (5% level); values are means ± SD
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Bitterness intensity (sensory) | boiling time Celeia boiled 45 min (ageing index 0.5) vs 5 min (0.3) | 2.4 ± 0.2 (BU 51, iso-alpha acids 50.2 mg/L) | 1.1 ± 0.3 (BU 45, iso-alpha acids 18.0 mg/L) | bitterness intensity 0–5, mean ± SD (10 people) | Sample compared more bitter No test reported |
| A small BU gap but large gaps in iso-alpha acids and intensity; hop ageing also differs; the test for this pair was not read; the authors report no correlation between chemical analysis and sensory results Where: Tables 7 and 8, Section 3.3 For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Trial beers; this pair differs in both boiling time and ageing | |||||
| Bitterness intensity (sensory) | same variety and boil, ageing only Styrian Wolf boiled 90 min at ageing index 0.3 vs 0.5 (BU 106 and 118) | 4.9 ± 0.2 (BU 106) | 3.4 ± 0.3 (BU 118) | bitterness intensity 0–5, mean ± SD (10 people) | Sample compared more bitter No test reported |
| The lower-BU beer had the higher mean intensity; the test for this pair cannot be confirmed from the text; some 45-min beers of this variety averaged 5.0, near the top of the scale Where: Tables 7 and 8 For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Same variety and boil with only ageing varied; the higher-BU beer had the lower mean intensity; the test for this pair cannot be confirmed | |||||
Ozaki & Wanikawa 2008 sensory only
官能評価と化学分析によるビールの“おいしさ”の解析. 日本醸造協会誌 103(3):150-162 — doi:10.6013/jbrewsocjapan1988.103.150
- How deeply checked
- Checked in full text — Full text of the J-STAGE PDF (a review article; sections 4-2 and 4-5, Fig. 4); figure values not read Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- 10 commercial beers and happoshu
- Processing and cooking
- 242 measurements across the whole study (including bitterness units, BU); the bitterness regression used water-soluble components
- How it was served or eaten
- Tasted as sold
- Who rated, on what scale
- 7 trained expert panellists; 28 attributes on line scales, 2 replicates each; PLS regression
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Bitterness intensity (sensory) | regression of bitterness Regression (PLS) of bitterness scores of 10 beers on water-soluble components | bitterness units (BU) the largest contributor | not given (values only in a figure) | rank of contribution in the regression (7 people) | Direction not given No test reported |
| The text gives no correlation value or direction; polyphenols, glucose and others are also listed Where: Section 4-5, Fig. 4 For whether more IBU or bitter compounds means people perceive more bitterness: Limited — BU explained bitterness scores best, but neither value nor direction is in the text; 10 beers | |||||
Ramos-Parra 2024 sensory only
Consumer insights into the at-home liking of commercial beers: Integrating nonvolatile and volatile flavor chemometrics. Food Science & Nutrition 12(6):4063-4075 — doi:10.1002/fsn3.4066
- How deeply checked
- Checked in full text — Full text via Europe PMC (text and Tables 1 and 2); the contents of Figs 2–4 not viewed Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- 6 commercial beers sold in Mexico (including 1 non-alcoholic pilsner)
- Processing and cooking
- IBU 10.8–53.8 (spectrophotometric), iso-alpha acids, plus colour, Brix, pH and acidity
- How it was served or eaten
- 30 mL tasted at home
- Who rated, on what scale
- 50 consumers; liking (15 cm line), check-all-that-apply emoji questions and just-about-right (JAR); no bitterness intensity score
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Bitterness intensity (sensory) | non-alcoholic Non-alcoholic pilsner (IBU 15.5) vs pilsner (IBU 16.8) | 42% "not bitter enough" | 54% "just about right" | share of just-about-right answers (50 people) | Direction not given No test reported |
| Not an intensity score; the abstract says IBU did not differ significantly and the text calls the IBUs similar, but the letters in Table 2 mark a significant difference (16.8 and 15.5); iso-alpha acids did not differ significantly (89.5 and 101.2 mg/L); pH differed significantly, acidity did not Where: Table 2, Fig. 2b For whether more IBU or bitter compounds means people perceive more bitterness: Limited — Liking and just-about-right answers rather than intensity; pH and more differ besides alcohol | |||||
Kishimoto 2021 composition only
「苦味価」は何を語っているのか？. 日本醸造協会誌 116(10):688-697 — doi:10.6013/jbrewsocjapan.116.688
- How deeply checked
- Checked in full text — Full text of the J-STAGE PDF (a review article; Table 2, Fig. 7); experimental details are in the English original (abstract only) Checked by: LLM (one extracted, another checked against the source; no human check), 2026-10-21.
- Samples
- Trial wort and beer brewed the same way with hop pellets aged 0–90 days at 40 °C
- Processing and cooking
- BU (spectrophotometric) and iso-alpha acids (HPLC) measured; taste-sensor readings were taken at 25 °C after adjusting all samples to 40 BU with unhopped beer
- How it was served or eaten
- Not applicable (no human tasting)
- Who rated, on what scale
- No human evaluation; bitterness measured by a taste sensor
| Measured | Comparison and condition | Sample compared | Comparison | Unit | Direction / test |
|---|---|---|---|---|---|
| Iso-alpha acids | aged hops Undiluted beer with fresh hops (day 0) vs aged hops (day 90); BU nearly the same | 39.9 mg/L (BU 47.5) | 2.2 mg/L (BU 49.9) | mg/L (beer) | Sample compared higher No test reported |
| With aged hops much of the BU came from oxidised compounds rather than iso-alpha acids; with all samples adjusted to 40 BU, the taste sensor's bitterness response fell for aged hops (not a human evaluation) Where: Table 2, Fig. 7 For whether more IBU or bitter compounds means people perceive more bitterness: Not usable — Compounds and a taste sensor, no human evaluation | |||||
What was established within an experiment
Only results where the same panel compared changed conditions within one study.
- Across 16 lagers, predicting bitterness scores from 6 compounds including iso-alpha acids gave a predicted-measured correlation of 0.92, and 3 single iso-alpha acids 0.54–0.74 (scores of 14 people after excluding 4 with extreme scores; the verifier could not check this against the source). [rows: Techakriengkrai 2004 predicted from 6 compounds]
- Across 250 commercial beers, iso-alpha acids and bitterness scores from a trained panel of 16 had a rank correlation of 0.68 (across styles). [rows: Schreurs 2024 iso-alpha acids and bitterness]
- In trial dry-hopped beers, 2 brews with the same reported mean BU of 22 (different variety and ageing) had mean intensities of 2.4 and 1.2. In a pair of the same variety with only ageing changed, BU fell from 39 to 34 while mean intensity went from 4.0 to 4.3, a gap that was not significant. [rows: Rutnik 2022 same BU; Rutnik 2022 same variety, ageing only]
- In trial kettle-hopped beers, 2 brews with close BU (45 and 51) had iso-alpha acids of 18.0 and 50.2 mg/L and intensities of 1.1 and 2.4 (boiling time and hop ageing also differed). In a pair of the same variety and boil with only ageing changed, the BU 106 beer had a higher mean intensity than the BU 118 one (4.9 vs 3.4). The authors report no correlation between chemical analysis and sensory results. [rows: Rutnik 2023 boiling time; Rutnik 2023 same variety and boil, ageing only]
- Brewing the same way with only hop ageing varied, BU of the undiluted beer stayed nearly the same (47.5 and 49.9) while iso-alpha acids fell from 39.9 to 2.2 mg/L. With samples adjusted to 40 BU, the taste sensor's bitterness response fell for aged hops (not a human evaluation). [rows: Kishimoto 2021 aged hops]
Candidate explanations for the differences
Conditions that differ between studies, or between beers, and could explain differences in bitterness. Several conditions differ at once, so which one mattered is unknown. These are candidates, not causes.
- What the bitter compounds are. BU is measured by the absorbance of an extract, so besides iso-alpha acids some compounds from aged hops or dry hopping also count. With the same BU, different contents may taste differently bitter (which compounds caused the gaps has not been established). [rows: Kishimoto 2021 aged hops; Rutnik 2022 same BU; Rutnik 2023 same variety and boil, ageing only]
- Alcohol. For a non-alcoholic pilsner, 42% said it was not bitter enough although iso-alpha acids did not differ significantly; but pH differed significantly, and the answers were about being just right, not intensity, so no effect of alcohol can be derived. [rows: Ramos-Parra 2024 non-alcoholic]
- Sweetness. Across 250 beers, sweetness and bitterness scores moved in opposite directions (ρ = −0.48). Sweetness may mask bitterness, but no experiment varied sugar. [rows: Schreurs 2024 iso-alpha acids and bitterness]
- Beer style. A correlation across styles may depend on which styles are included; in which direction and how much has not been tested. [rows: Schreurs 2024 iso-alpha acids and bitterness; Techakriengkrai 2004 predicted from 6 compounds]
What is not known — what this comparison alone cannot separate
- Which of sugar, carbonation, pH or alcohol drives the gap between IBU and bitterness cannot be separated from the comparisons included here. [rows: Ramos-Parra 2024 non-alcoholic; Schreurs 2024 iso-alpha acids and bitterness]
- Whether bitterness levels off at high IBU: the study reporting a non-linear link between BU and intensity could be read only as an abstract, which does not say whether it levels off (see the sources table). Within this table, one pair of the same variety had the lower mean intensity at the higher BU. [rows: Rutnik 2023 same variety and boil, ageing only]
- Panellist differences: one study excluded 4 panellists from its prediction, and some trial beers averaged near the top of the scale. Whether gaps in bitterness come from the compounds or from panellist variation cannot be separated. [rows: Techakriengkrai 2004 predicted from 6 compounds; Rutnik 2023 same variety and boil, ageing only]
How studies and rows were counted
The number of evidence rows is not the number of studies. Table rows, ledger evidence rows, papers and research groups are counted separately.
- Sources in the table: 7, of which 6 have results on people's bitterness ratings in this table; for the others, only results on something else (compounds, smell) are shown, or they are used only for context.
- Rows in the table (study × measured result): 9. Rows on perceived bitterness: 8.
- Evidence rows in the lab's ledger these rows rest on: 0. One paper can supply several rows. Rows without a ledger evidence row come from other tables of the same papers, or from sources newly read for this question.
- Research groups among the studies with bitterness results in this table, as grouped in the ledger: 5 (reports from the same lab count as 1; co-authors and affiliations can overlap, so this is not a count of independent replications).
What we looked at
The sources examined for this question, why each was included or excluded, and which full texts could not be reached. We searched Europe PMC, J-STAGE and CiNii for studies on sensory beer bitterness with IBU or iso-alpha acids, and added the sources already in the lab's ledger.
| Source | Decision | Why |
|---|---|---|
| Relationships of Sensory Bitterness in Lager Beers to Iso-alpha-Acid Contents (2004) doi | Included in the table | Set human bitterness against compounds in commercial lagers; read in full by the reader, but the verifier could not retrieve the source |
| Predicting and improving complex beer flavor through machine learning (2024) doi | Included in the table | Set iso-alpha acids against bitterness in 250 beers; read in full |
| Impact of Hop Freshness on Dry Hopped Beer Quality (2022) doi | Included in the table | Set BU against intensity in trial beers; read in full |
| The Impact of Hop Freshness on Kettle-Hopped Beers (2023) doi | Included in the table | Set BU and iso-alpha acids against intensity in trial beers; read in full |
| 官能評価と化学分析によるビールの“おいしさ”の解析 (2008) doi | Included in the table | Set BU against bitterness scores in 10 beers by regression; read in full (review article) |
| Consumer insights into the at-home liking of commercial beers: Integrating nonvolatile and volatile flavor chemometrics (2024) doi | Included in the table | Set IBU against consumer answers; read in full |
| 「苦味価」は何を語っているのか？ (2021) doi | Included in the table | Brewed beers with nearly the same undiluted BU but different contents (sensor readings at 40 BU); read in full (review article) |
| Evaluation of Nonvolatile Chemistry Affecting Sensory Bitterness Intensity of Highly Hopped Beers (2018) doi | Full text not reachable | Reports BU predicting bitterness non-linearly; abstract only, with no direction or values in it |
| The impact of hop bitter acid and polyphenol profiles on the perceived bitterness of beer (2016) doi | Read as context (not in the table) | Compared the character of bitterness by word choice; no intensity scores, and BU not compared directly with sensory results (read as accepted manuscript) |
| Bitterness Intensity of Oxidized Hop Acids: Humulinones and Hulupones (2016) doi | Read as context (not in the table) | Compared the bitterness of oxidised hop acids with iso-alpha acids; abstract only |
| Toward Understanding the Bitterness of Dry-Hopped Beer (2017) doi | Read as context (not in the table) | Studied how dry hopping raises IBU and bitterness; abstract only |
| The Human Bitterness Detection Threshold of Iso-α-Acids and Tetrahydro-Iso-α-Acids in Lager Beer (2009) doi | Read as context (not in the table) | A detection threshold (present or absent), not an intensity comparison; abstract only |
| Exploring the flavor life cycle of beers with varying alcohol content (2017) doi | Read as context (not in the table) | Compared when bitterness dominated in beers of different alcohol content; no IBU or hop compound measurements are reported |
Read in the encyclopedia
- Bitterness units (BU, IBU) — the measure in this question
- Iso-alpha acids — the main bitter compounds of beer
- What Is IBU? Beer Bitterness Units vs. the Taste — the topic hub on IBU
- IBU Does Not Measure Bitterness — a research note on IBU and perceived bitterness
Source ledger
Each study's source can be reached from its section above. All of the lab's sources are listed in the source ledger.
How to cite this page
Aoki, M. (NIGAMI LAB) (2026). Do beers with higher IBU taste more bitter?. https://nigamilab.com/en/topics/ibu-bitterness/
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