Updated: The Impact of Fermentation Research & Quality | #PSC 172

By Clay Gordon | 12 days ago | | 10 min read

Original photo Clay Gordon – Venezuela 2006

Episode 172 of #PodSaveChocolate takes a look at research on cocoa fermentation published in 2025 (with some context from 2021). Is it useful? Usable?

When and Where to Watch

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This stream begins at 11:00 MST (10:00 PST, 12:00 CST, 1:00 pm EST), on Friday, Jan 2nd, 2026.

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Overview - Episode 172

Episode 172 of PodSaveChocolate examines one of the crucial steps in the cocoa-to-chocolate production process: fermentation. 2025 saw some fascinating new research, especially when it comes to identifying specific microbial contributors to flavor.

Note: There has been field work on fermentation approaches that have NOT been published in peer-reviewed journals. That field work will not be discussed here as there is no independent review of the findings. That does not mean the field work is not important or has no value, just that the reported results (many of which have amassed anecdotal support) have not been peer-reviewed.

Before We Begin – The TL;DR on the Market

Share: Fine/flavor cocoa represents ~5–8% of global production; historical references cite ~9% (~263,000 MT in 2017). ⁠ ⁠
Tonnage: Applying 5–8% to recent world output yields an indicative range of ~250,000–400,000 MT annually. ⁠
Pricing: At a daily price (average) of about ~US$6,000/MT; fine/flavor typically commands ~20–30% premiums. ⁠
Value: Estimated market value band ~US$1.7–3.0B, derived from 240,000 MT × US$7,200/MT and 384,000 MT × US$7,800/MT calculations. ⁠
Reporting: ICCO’s Ad Hoc Panel classifies origins as fine/flavor; ICCO does not publish a standalone annual fine/flavor tonnage series in public datasets. Authoritative production and price series are in the Quarterly Bulletin of Cocoa Statistics.
There is still value in pure research that is independent of market applicability or acceptance.

The TL;DR (Fermentation)

What fermentation is doing inside and outside the bean

Outside (in the pulp): Yeasts first digest sugars anaerobically, producing ethanol and heat; pectins break down so the mass drains and oxygen enters. Lactic acid bacteria flourish early; then, with more oxygen and rising temperatures, acetic acid bacteria convert ethanol to acetic acid. This acid and heat diffuse inward.
Inside the bean: Heat and acids kill the embryo, membranes rupture, and stored substrates mix. Enzymes (aspartic endoproteases and carboxypeptidases) begin selectively cutting storage proteins (especially 7S vicilin globulins), releasing hydrophobic amino acids and short peptides—the building blocks for Maillard reactions during roasting. Polyphenol oxidase and peroxidase drive oxidation of polyphenols into tannins, reducing astringency and bitterness.

Why temperature and pH matter most

Enzyme sweet spot: The proteases that generate aroma precursors are most effective when bean pH sits roughly 5.0–5.5; peroxidase activity is strong around ~5–5.5. Keep pH too low for too long and proteolysis stalls; too high and oxidation to tame astringency lags.
Thermal profile: A rapid early rise (as yeasts work) followed by a controlled mid-phase temperature helps both microbial succession and enzyme kinetics. Sustained, moderate warmth promotes polyphenol transformation and protein breakdown without baking the mass or trapping excessive acid.

Typical dynamics observed

Pulp total soluble solids plunge in the first 48–72 hours; lactic and acetic acids peak around days 2–3 and then diffuse into beans.
Bean pH falls early and should recover toward ~5–5.6 by the end; proteins drop ~12–16% as amino acids are liberated; epicatechin, catechin, and procyanidins decline substantially, cutting astringency; fats and fatty acid profiles barely change.

How these trajectories shape flavor

When bean pH rebounds into the ~5.0–5.5 window near the end, protease + carboxypeptidase synergy yields a richer pool of precursors—more cocoa and nut notes after roasting, with less bitterness/astringency.
Too cool or poorly insulated fermenters lose heat, slowing succession and enzyme action, often yielding flatter, more acidic profiles.
Too acidic (pH < 4.75 prolonged) or excessively hot/poorly ventilated runs can lock in sharp, vinegary notes and suppress desirable complexity.

Practical signals to watch during a heap or box fermentation

Temperature: Track core-mass temperature, aiming for a brisk early climb and a stable mid-phase plateau rather than spikes or long cool periods.
pH: Measure bean (or cotyledon slurry) pH daily; a healthy curve dips and then returns toward ~5–5.6.
Draining/aeration: Good pulp drainage and timely turns improve oxygen ingress, supporting the acetic phase and acid clearance.
Cut test: Progressively browner beans indicate internal reactions are advancing; purple/grey suggests under-fermentation.

Nuances worth noting

Optimal temperatures are phase- and origin-dependent. Field data often favor averages near ~40°C; controlled studies sometimes show benefits from mid‑40s °C late in fermentation if pH is managed and ventilation prevents over-acidification.
Genotype, maturity, ambient climate, and box design (size, insulation, airflow) all modulate heat retention and acid dynamics—so “right ranges” should be tuned to a specific locale and infrastructure (e.g., box, tray, heap) rather than copied wholesale.

Research Published in 2025

TL;DR: Defined, metabolically competent starter cultures can reliably reproduce and tune fine-flavour chocolate under controlled fermentation, enabling industrial consistency while retaining origin-linked diversity.

TL;DR: Fermentation creates sensory precursors while trading off certain antioxidants and minerals; NF (non-fermented) retains bioactives but shows higher oxidative markers. Clone responses are genotype-dependent, enabling targeted selection and blending strategies to balance flavor and functionality. The overall implication: choose clones and fermentation regimes deliberately—CCN 51, EEOP 63, CEPEC 5, EEOP 96 emerge as strategic options—to optimize both product quality and health-related traits.

Antioxidant “health” messaging should avoid overreach: fermentation reduces certain polyphenols; NF retains them but also shows higher oxidative markers (MDA) and lower enzyme-mediated defenses; net functional impact depends on downstream processing (roasting, alkalization), dose, and bioavailability.

Mineral enhancements in F(ermented) (K, Mg) are context-dependent; reported directions vary by fermentation system and turning/leaching dynamics; specify process conditions if making nutritional claims.

Colombia – Hyperspectral imaging is an approach I have been promoting since 2018 as a way to improve quality assessments

One Key Result: Regulatory relevance – the inclusion of cadmium measurements aligns data utility with EU 488/2014 compliance analytics for export markets. This enables model development that flags high‑risk lots before processing

Multi-country study; when combined with hyper-spectral imaging these two techniques can very quickly identify smuggling.

TL;DR: correlation networks of LC-MS profiles provide an unsupervised, scalable framework to fingerprint cocoa by stage first and origin second as correlation thresholds increase.

Other Coverage

See also episode 68 – Cacao Fermentation 101

Bertus Eskes' cocoa fermentation research focuses on innovative methods like Anima, Tradima, and TropMix, which aim to create high-quality fine cocoa and unique flavors by manipulating pulp environment, sometimes adding fruit pulps or spices to develop specific aromas and reduce reliance on traditional Dutching, revealing 43 natural flavors and 31 fruit/flower traits in cocoa, with data available through his publications and interviews on platforms like The Chocolate Life(!) and ResearchGate.

Summary Tables

Fermentation Process Overview

Metric	Value/Range	Notes
Fine flavor cocoa market share	5-8% of global production	Historical references up to 9%
Fine flavor cocoa annual production	250,000 - 400,000 metric tons	Based on 5-8% range
Price premium for fine flavor cocoa	20-30%, up to 50%+	Depends on genetics, producing country, fermentation method
Price range per metric ton (example)	$7,200 - $8,000	Based on $6,000 commodity cocoa price + premiums
Estimated market value	$1.7 billion - $3 billion	For fine flavor cocoa market
Overall chocolate market size	$180+ billion	Specialty cocoa is a small niche in comparison

Quantitative Data and Market Overview

Stage	Microbial Activity	Key Chemical Changes	Impact on Bean
Initial (Anaerobic)	Yeasts ferment sugars → ethanol + heat	Pectin breakdown, pulp liquefies (TSS drops)	Heat and ethanol penetrate bean; embryo killed
Mid-phase (Aerobic)	Lactic acid bacteria flourish	pH changes; lactic acid production	Enzymes activated inside bean break down proteins and sugars into flavor precursors
Late-phase (Aerobic)	Acetic acid bacteria convert ethanol → acetic acid	Acetic acid and heat diffuse inward	Oxidation of polyphenols reduces bitterness and astringency

Comments? Questions?

If you have questions or want to comment, you can do so during the episode or, if you are a ChocolateLife member, add them in the Comments below at any time.

Episode Hashtags and Socials

#ferment #fermented #fermentation
#cocoa #cacao #cacau
#chocolate #chocolat
#specialtychocolate #craftchocolate #beantobar
#PodSaveChoc #LaVidaCocoa #TheChocolateLife

Future Episodes

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Tue, January 6th Ep 173
Why Agriculture? Was it Fermentation? Beer?!

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