Category: News

A new scientific breakthrough has uncovered a novel use for one of coffee’s most overlooked by-products. Researchers from Chiang Mai University have demonstrated that coffee parchment, the papery husk surrounding coffee beans, can serve as a functional feed additive in aquaculture — with significant benefits for Nile tilapia.

Published in the peer-reviewed journal Scientific Reports, the study shows that incorporating modest amounts of coffee parchment into fish feed not only improves growth and feed efficiency but also strengthens the immune system and enhances gut microbiota. The findings align with broader sustainability goals by transforming coffee waste into a valuable asset for the aquaculture sector.

Turning Coffee Waste into Aquafeed

Coffee parchment, a fibrous layer removed during the post-harvest process, makes up around 12% of the coffee cherry’s weight and is typically discarded. Despite its rich content of fiber and bioactive compounds such as polyphenols, caffeine, and flavonoids, its potential applications have remained largely untapped — until now.

In this eight-week feeding trial, scientists evaluated the effects of varying levels of parchment (0, 5, 10, 20, and 40 grams per kilogram of feed) on 300 Nile tilapia fingerlings reared in a biofloc system, an environmentally friendly aquaculture method that recycles organic matter through microbial activity.

Growth and Immunity Enhanced at Optimal Doses

The results were striking. Fish that received 5 g/kg of coffee parchment (CP5 group) exhibited:

• Significant increases in weight gain and feed conversion efficiency

• Higher survival rates

• Upregulation of genes linked to growth, such as ghrelin and galanin

Importantly, the CP5 group also showed marked improvement in immune responses:

• Elevated lysozyme and peroxidase activity in both skin mucus and blood serum

• Enhanced expression of immune-related genes including IL-1β, TNF-α, NFkB, and MHC II-α

Regression analysis identified an optimal dosage range of 15.06–19.86 g/kg, beyond which the benefits declined, likely due to the high fiber content limiting nutrient absorption.

A Healthier Gut Microbiome

The study also revealed profound effects on the fish gut microbiome. Notably:

• The CP10 group displayed the highest microbial diversity

• A significant reduction in Proteobacteria, a phylum associated with inflammation

• An increase in Cetobacterium, a beneficial genus linked to vitamin B12 production and improved digestion

These changes suggest that coffee parchment may act as a prebiotic, supporting a healthier intestinal environment — a key determinant of fish health and performance.

Environmental and Economic Implications

With global coffee production expected to exceed 172 million 60-kg bags in 2024–25, the industry generates an estimated 6 million tons of organic waste each year. The majority of this by-product ends up in landfills or is incinerated.

By repurposing parchment for aquaculture feed, this research offers a scalable solution that:

• Reduces environmental waste

• Cuts feed costs in fish farming

• Supports a circular economy by reintegrating agro-industrial by-products

The Role of Biofloc Systems

The integration of coffee parchment was especially effective in the biofloc system, which is gaining popularity for its ability to minimize environmental impact while improving nutrient cycling.

In this study, coffee parchment not only served as a feed additive but also contributed carbon to the floc environment, stimulating microbial activity and reducing nitrogen waste — reinforcing its role as a dual-function input.

Next Steps for Validation

While the results are promising, the authors note that further studies are needed:

• In commercial aquaculture settings

• Over longer production cycles

• Including pathogen challenge tests to confirm disease resistance benefits

They also recommend exploring higher dosage thresholds and metabolomic analyses to better understand how coffee parchment modulates fish physiology.

Conclusion

This pioneering research opens the door to a sustainable, science-backed application of coffee waste — one that benefits aquaculture, reduces environmental burden, and adds value to the global coffee supply chain. Coffee parchment, once a discarded husk, may soon find itself at the center of a greener, more efficient food system.

Study Reference:
Hien Van Doan et al., “Impacts of coffee parchment on growth, immunity, and gut microbiota of Nile tilapia in biofloc system,” Scientific Reports (2025) 15:25057. https://doi.org/10.1038/s41598-025-03109-1

A groundbreaking study reveals how just two afternoon cups of coffee can disrupt deep sleep and reshape brain activity — especially in young adults.

If you’re in the habit of enjoying coffee in the afternoon, you might want to reconsider. A recent study conducted by researchers at the University of Montréal and published in Communications Biology found that even moderate doses of caffeine after midday can significantly alter how the brain functions during sleep — particularly in the crucial non-REM stages, which are responsible for the body’s restoration.

The study goes far beyond typical sleep hygiene advice. It details, with scientific precision, how caffeine affects the structure of brain activity and highlights age-related differences in how this stimulant disrupts our sleep cycles.

Inside the Study: How It Was Conducted

The research team recruited 40 healthy adults aged between 20 and 58, all with moderate caffeine habits. Each participant spent two nights at a sleep lab under carefully controlled conditions:

• On one night, participants consumed 200 mg of caffeine — the equivalent of about two cups of coffee.

• On the other, they were given a placebo.

• Neither the participants nor the researchers knew which treatment was administered on which night (a double-blind study).

During both nights, the team monitored each subject’s brain activity using electroencephalography (EEG) — a tool that captures electrical signals in the brain while sleeping.

A Hyperactive Brain During Sleep

The EEG readings revealed remarkable changes when participants consumed caffeine:

• Brain signals were more random and complex, especially during non-REM sleep, which is the stage where deep rest and body repair typically occur.

• Brain activity appeared to resemble a “critical state,” a condition of heightened responsiveness often seen during wakefulness.

• Non-REM sleep became shallower, reducing the depth and effectiveness of recovery.

“Caffeine delays but does not prevent sleep,” said lead researcher Prof. Philipp Thölke. “Even though we can sleep under the influence of caffeine, the brain — and therefore also sleep — is impacted. It leads to shallower sleep with increased information processing during the sleep stages where the brain normally enters deep restorative rest.”

Younger Adults Are More Vulnerable

Interestingly, the study found that age plays a major role in how caffeine impacts sleep. Among participants:

• Younger adults (ages 20–27) were more strongly affected during REM sleep, the stage associated with dreaming and emotional processing.

• Older participants (ages 41–58) showed less disruption during REM, which researchers believe may be due to age-related changes in adenosine receptors — brain structures that regulate sleep pressure.

Caffeine blocks adenosine receptors, which is how it keeps us alert. Since older adults have fewer of these receptors, caffeine’s effects are somewhat blunted in this group — at least during REM sleep. However, the disruption of non-REM sleep was observed across all age groups.

Why This Matters

While caffeine is consumed daily by billions, this study highlights that even a modest amount taken after noon can significantly alter the structure and quality of sleep. Over time, this can contribute to:

• Chronic fatigue

• Weakened immune function

• Impaired memory and cognitive performance

• Increased risk of heart disease, diabetes, and mood disorders

Sleep experts have long warned that sleep is not just about duration — depth and brain rhythm are equally important, and caffeine interferes with both.

Important Caveats

• The study was conducted exclusively on healthy adults with no diagnosed sleep disorders.

• It may not apply to people with neurological or psychiatric conditions like Parkinson’s disease, insomnia, or anxiety.

• Individual sensitivity to caffeine varies and may be influenced by genetics and long-term habits.

Final Takeaway: Rethinking Your Coffee Cutoff Time

So when should you stop drinking coffee? While there’s no universal answer, this study reinforces a common rule of thumb: avoid caffeine after noon if you want to ensure deeper, more restorative sleep.

You don’t need to give up coffee — but you should be mindful of when you consume it.

Sources

• Original Study – Communications Biology (Nature)

• University of Montréal Press Release

• PsyPost: Study Summary

We’re excited to continue our “Barista Terminology” series on QahwaWorld.com—your guide to mastering essential coffee concepts and café communication. In Episode 8, we shift our focus from brewing tools to human connection, exploring the key customer service terms that shape the hospitality experience in cafés. From “dine-in” to “guest experience,” this episode breaks down the language baristas use to ensure service is smooth, professional, and warmly memorable. Whether you’re new behind the bar or refining your service style, these terms are the foundation of great customer interaction.

Great coffee is only part of the café experience. How a barista communicates with guests — from the moment they enter to the moment they leave — defines hospitality. In this episode, we explore key customer service terms and phrases used in café environments to ensure efficiency, clarity, and warmth in daily interactions.

1. Dine-In

A customer who will enjoy their coffee at the café. Orders are typically served in ceramic cups.

2. Takeaway

A customer who wants their order to-go. Drinks are usually served in disposable cups.

3. Order Queue

The list or sequence of pending orders. Helps baristas organize workflow and prioritize drinks.

4. Call Out

Announcing a customer’s name or order when it’s ready. Often used in busy cafés to avoid confusion.

5. Modifiers

Customizations or changes a customer requests, such as extra milk, decaf, no sugar, or plant-based alternatives.

6. Double

A request for a double shot of espresso instead of a single — common in milk-based drinks like lattes.

7. Upselling

A polite suggestion to enhance the customer’s order, such as adding a pastry, using premium beans, or upgrading to a larger size.

8. Regulars

Customers who visit frequently and are familiar with the menu and staff. Building rapport with them improves loyalty and atmosphere.

9. Allergen Alert

Flagging ingredients like nuts, soy, or dairy that may cause allergic reactions. Essential for customer safety.

10. Wait Time

Estimated time a customer will wait for their order. Good communication reduces frustration and manages expectations.

11. Customer Flow

Refers to the pattern of how customers move through the café — from entrance, to order point, to pickup or seating. Important for layout and efficiency.

12. Smile in the Voice

A service expression meaning to speak warmly and helpfully, especially when customers cannot see your face (e.g., over the phone or behind a mask).

13. Bar Call

Communication between baristas (e.g., “Double cappuccino for here!”). Helps coordinate timing and clarity.

14. Last Call

A final notice before closing time, informing customers that the café will close soon and last orders should be placed.

15. Guest Experience

The overall impression a customer has from their visit — includes service, cleanliness, friendliness, and coffee quality.

Related Stories:

Barista Terminology | Episode 7: Water & Temperature Control

Barista Terminology | Episode 6: Grind & Extraction Variables

Barista Terminology | Episode 5: Milk Texturing & Latte Art

Barista Terminology | Episode 4: Brew Methods Explained

Barista Terminology | Episode 1: The Coffee Bean – From Seed to Roast

Barista Terminology | Episode 2: Barista Tools & Equipment

Barista Terminology | Episode 3: Espresso Basics

In the world of specialty coffee, few words are praised as often — and understood as little — as “balance.” Baristas champion it. Roasters chase it. Judges score it. But what does balance in coffee really mean?

To the untrained ear, balance may sound like neutrality, a lack of extremes. But to the sensory professional or curious enthusiast, balance is something much deeper — a dynamic harmony between opposing forces: sweet and bitter, acidic and smooth, sharp and mellow. It is not about muting flavors but orchestrating them.

From Biology to the Brew: Understanding Taste

Our experience of balance begins with biology. The human tongue detects four primary tastes: sweet, sour, salty, and bitter. Each is sensed more intensely in specific regions of the tongue — sweetness at the tip, bitterness at the back, and saltiness and sourness along the sides.

But coffee, like wine, is more than the sum of its taste parts. It is shaped by interactions — modulations — that change how we perceive those core flavors. Acidity can amplify sweetness, salt can mellow bitterness, and sugar can mask sharp sour notes. These taste interactions are where the magic of balance begins.

The Six Modulations: Crafting a Cohesive Cup

According to sensory research and practices endorsed by the Specialty Coffee Association, six primary taste interactions determine the flavor profile of a cup:

1. Acids + Sugars → Acidy
   A bright, juicy cup — like a lightly roasted Ethiopian — where acidity enhances fruity sweetness.

2. Salts + Sugars → Mellow
   Found in low-acid or Brazilian coffees, where natural salts soften sharpness and smooth out the flavor.

3. Sugars + Acids → Winey
   Prominent in fermented or honey-processed coffees. Sweetness softens acidity, evoking wine or dried fruit notes.

4. Sugars + Salts → Bland
   When sugar dominates too much, the cup feels flat and underwhelming. Complexity is lost.

5. Acids + Salts → Sharp
   A common issue in underdosed espresso or overly bright brews. Lacking sweetness, the acidity and saltiness clash.

6. Salts + Acids → Soury
   Overly mineral-heavy or dark roasted coffees may dampen acidity, leading to a dull finish.

These modulations aren’t just curiosities. They’re tools for roasters, baristas, and tasters who want to shape a balanced experience. And they underscore a critical truth: balance isn’t accidental — it’s engineered.

The Roaster’s Role: Designing for Balance

In the roastery, balance begins with green coffee selection. A washed Guatemalan coffee with bright acidity may be paired with a naturally processed Brazil for body and sweetness. Roast curves are carefully adjusted to retain or mute specific acids. Post-roast, blending becomes a strategic act of flavor engineering.

And yet, balance is not reserved for blends. A single-origin can be balanced too — if the inherent sugars, acids, and salts are in the right proportion, and the roast development nurtures their harmony.

Barista and Brewer: The Final Sculptor

Once roasted, brewing becomes the final step in modulating balance. Brew ratio, temperature, grind size, and water quality all influence how each taste emerges. Too coarse, and sweetness is lost. Too fine, and bitterness overwhelms. A well-calibrated pour-over reveals not only the origin but also the balance that was coaxed throughout the process.

Why Balance Matters

In coffee competitions, balance is often the deciding factor between a high-quality cup and a great one. It reflects a coffee’s completeness — a seamless transition from start to finish, with no single note dominating. A balanced cup feels structured, intentional, and elegant.

For everyday drinkers, balance matters because it makes coffee enjoyable. A well-balanced brew is more forgiving, more memorable, and more emotionally satisfying. It doesn’t fatigue the palate or require explanation. It simply feels “right.”

Final Brew Thought

As coffee drinkers, we’ve learned to praise complexity and intensity. But complexity without balance can feel chaotic. True balance is the mark of craftsmanship — from farm to roastery to cup.

In the words of seasoned cuppers, the best coffee doesn’t just taste good — it feels whole.

In an ambitious feat of scientific collaboration, World Coffee Research (WCR) and an extensive network of global partners have released the most expansive field-based evaluation of Coffea arabica varietal resistance to coffee leaf rust (CLR) in history. Published in Frontiers in Plant Science, the study represents a turning point in how the world understands the interplay between coffee genetics and diverse agroecological environments. More than just an academic endeavor, this research brings critical, field-tested knowledge directly into the hands of farmers and breeders around the globe.

Spanning 15 countries, 23 research sites, and 29 coffee varieties, the International Multilocation Variety Trial (IMLVT) was designed to tackle the mounting challenge of CLR—a fungal disease that has haunted coffee farms for more than a century. Caused by Hemileia vastatrix, CLR threatens the economic sustainability of coffee-growing communities across Latin America, Africa, and Asia, with estimated yield losses between 35% and 75% during severe outbreaks.

Dr. Tania Humphrey, Scientific Director of WCR, emphasized the urgency and significance of the trial: “No single country or institution can solve the complex challenges facing coffee on its own. This trial demonstrates the power of global collaboration. By pooling data, expertise, and resources, we’ve produced insights that no single country could have achieved in isolation.”

Understanding the Scope and Impact of Coffee Leaf Rust

Coffee leaf rust is not a new phenomenon. Since its first documentation in commercial coffee in Sri Lanka in 1869, the pathogen has marched steadily across coffee-growing regions. It reached Latin America in the 1970s and made its most recent jump to Hawaii in 2020. Its ability to adapt and evolve means traditional containment methods such as fungicides and shading are insufficient in the long term.

With over 55 known physiological races of H. vastatrix, resistance to rust is increasingly seen as a moving target. Arabica coffee’s resistance genes—designated SH1 through SH9—have been introgressed from wild coffee species like C. canephora and C. liberica into commercial varieties. But these genes alone cannot outpace a pathogen that continues to evolve in complexity and virulence.

The IMLVT: A Landmark in Coffee Research

Launched in 2015, the IMLVT program was designed to identify the best-performing Arabica varieties in real-world conditions. The trials incorporated varieties from 11 breeding programs across diverse agroclimatic zones, from the dry, high-altitude plains of Zambia to the wet, shaded plantations in Indonesia.

Of the 31 varieties originally included, 29 were ultimately analyzed based on data integrity from 23 viable research sites. The trial allowed researchers to identify both globally stable performers and those suited to specific local conditions. Importantly, the research accounted for genotype-by-environment (GxE) interactions, confirming that a coffee plant’s resistance to rust is not determined solely by its DNA, but also by where and how it is grown.

Dr. Jorge C. Berny Mier y Teran, WCR’s lead scientist on the study, noted: “This is more than a rust resistance trial—it’s a foundational step toward smarter breeding. By evaluating how genotypes behave in different environments, we’re equipping breeders and policymakers with the tools to deploy varieties where they’ll thrive.”

Key Findings: Resistance, Stability, and Adaptation

Among the most rust-resistant varieties identified were EC16 (commercially known as Mundo Maya), Ruiru 11, Parainema, Catigua MG2, and IPR107. While EC16 recorded the lowest average rust score across all sites, its performance was inconsistent in certain regions. Parainema and Kartika 1, however, combined high resistance with strong stability, making them versatile candidates for widespread cultivation.

The study highlighted that pure Arabica varieties tended to show higher susceptibility to rust, whereas interspecific hybrids—particularly those with Timor hybrid parentage—offered stronger resistance. However, no variety demonstrated absolute immunity, underscoring the need for continuous surveillance and breeding innovation.

The Environmental Variable: No One-Size-Fits-All

Resistance was also found to be deeply influenced by site-specific environmental factors. Climate, altitude, rust strain diversity, and even agricultural practices contributed to varietal performance. Using advanced statistical tools like the GGE biplot and the WAASB model, the researchers identified four macro-environments or “mega-zones” that captured the variation across regions. Each zone had its own top-performing varieties and unique challenges.

For instance, Catigua MG2 thrived in India, Indonesia, and El Salvador, while EC16 and Ruiru 11 dominated in East Africa and parts of Central and South America. This knowledge enables breeders to tailor varietal recommendations more precisely, improving outcomes for smallholder farmers.

Albertino Meza, Agricultural Research Manager at CENFROCAFE, Peru, one of the trial’s host sites, remarked: “We now have evidence that empowers farmers. They can select varieties based on actual field data, not assumptions. This improves yield, resilience, and ultimately, livelihoods.”

Practical Implications for the Global Coffee Sector

The IMLVT trial provides direct benefits to multiple stakeholders in the coffee value chain:

• Breeders gain clear data on which parent lines offer reliable resistance.
• Producers get tools to select the right variety for their environment.
• Governments and NGOs can shape agricultural policies and training programs based on proven outcomes.
• Exporters and roasters gain a more stable supply of high-quality beans.

As the effects of climate change continue to amplify disease risks in agricultural systems, the value of such international research grows. With global coffee production facing volatility from both biological and environmental stressors, strategies rooted in collaboration, science, and adaptability are no longer optional—they are essential.

Building Scientific Infrastructure and Capacity

The trial didn’t only generate scientific knowledge; it also enhanced infrastructure and human capacity in the host countries. Partner institutions received equipment, training, and support to continue advanced agronomic research, building local resilience beyond the lifespan of the project.

“We’re building more than disease resistance—we’re building networks of trust and capability,” Dr. Humphrey said. “This trial sets a precedent for how global agriculture can respond to shared threats.”

Looking Ahead: Toward Next-Generation Coffee

With rust resistance proving variable across locations, the study underscores the need for ongoing multilocation trials, deeper genetic mapping, and surveillance for rust race evolution. It also opens pathways for stacking resistance genes, as previously proposed by Eskes and others, to provide more durable protection.

The study’s GxE framework also provides a template for evaluating other key traits, such as drought tolerance, cup quality, and yield potential. The future of coffee breeding is not just about one trait or one country—it’s about designing resilient, high-performing varieties for a complex and changing world.

The data is publicly available, serving as a resource for breeders, producers, and researchers. It also serves as a call to action: the future of coffee depends not only on preserving quality but on building systemic resilience. With shared science and shared purpose, the coffee community can rise to meet that challenge.

Download the full study: Global Coffea arabica variety trials reveal genotype-by-environment interactions in resistance to coffee leaf rust (Hemileia vastatrix) published in Frontiers in Plant Science.