You stumble into kitchen half awake and start brewing coffee. Before you have taken single sip, aroma fills room. Morning seems more manageable. But what just happened? No caffeine has entered bloodstream. Coffee hasn’t touched lips. Yet your brain may be responding.
Could smell of coffee alone change how you feel?
Previous studies have linked coffee aroma with shifts in mood, memory, stress, and brain activity. But these responses were usually examined separately, leaving question unanswered: When coffee changes how someone feels, do brain and body respond together?
Researchers at Showa Pharmaceutical University in Japan investigated that moment. Their study, published in Nutrients, involved 20 university students aged 20 to 29.
They tracked mood, brainwaves, heart rate, and heart rate variability as volunteers sat beside freshly brewed coffee – without drinking it. Within 5 minutes, participants reported fewer negative feelings and showed shift in EEG-derived index linked to relaxation. Their hearts, however, appeared unchanged.
How Study Measured Coffee Aroma Without Drinking – 20g Coffee 50cm Away
Researchers brewed 20 grams of ground coffee with 400 milliliters of water heated to 85 °C 185 °F. They placed drink in glass server around 50 centimeters 20 inches from each participant.
Volunteers sat and breathed normally as aroma spread through room. Before and after this aromatic pause, participants completed questionnaire assessing tension and anxiety, depression and dejection, anger and hostility, vigor, fatigue, and confusion.
Brain activity and heart rate were recorded using portable headband, while heart rate variability was measured with separate wearable device.
After 5 minutes with coffee aroma, participants’ mood disturbance scores had fallen. They reported less fatigue, tension and anxiety, confusion, depression, and dejection. After adjustment for multiple statistical comparisons, reductions in fatigue, tension and anxiety, confusion, and depression and dejection remained significant. Vigor, however, did not increase significantly. Aroma appeared to be associated less with sudden rush of energy than with turning down volume on negative feelings.
Brain Relaxation Index Rose – But Heart Did Not Join Coffee Break
Researchers detected increase in EEG-derived relaxation index, calculated from relative contributions of alpha, beta, and theta brainwave activity. That might sound as though participants’ brains relaxed at first whiff of coffee. But result needs careful pour of caution. Although standardized effect size was large, absolute increase was modest. Scientists also don’t know whether change of this magnitude represents physiologically meaningful relaxation.
Finding therefore shows change in calculated EEG index, not proof that coffee aroma relaxed brain. Meanwhile, heart didn’t appear to join coffee break. Neither heart rate nor heart rate variability changed significantly.
Participants who reported greatest mood improvements did not necessarily show largest EEG changes. At individual level, shifts in mood, brain activity, heart rate, and heart rate variability were not significantly correlated. This helps answer researchers’ original question. Mood and EEG activity may both change across group without reflecting one coordinated response.
Why Smell Alone Might Affect Mood – Memory Emotion And Expectation
It isn’t difficult to imagine why coffee might influence how we feel. Sense of smell is closely connected to brain systems involved in emotion and memory. Familiar scent can summon person, place, or feeling before we consciously identify it. Coffee carries plenty of associations. Its aroma may signal morning, warmth, break from work, conversation with friend, or promise of caffeine.
Separate 2018 study found people performed better on analytical tasks when exposed to coffee-like scent. Smell raised expectations of performing well, suggesting learned associations or placebo-like effect may contribute. That leads to study’s biggest limitation: There was no control condition.
Analysis: No Control Room, Small Sample, Young Students Only
Researchers did not compare coffee aroma with odor-free room, unrelated scent, or placebo. Consequently, they cannot determine whether coffee produced changes.
Five minutes of quiet rest might have improved participants’ moods. They may also have become comfortable in laboratory or expected coffee to make them feel better.
Researchers did not systematically assess how often volunteers drank coffee, whether they liked it, their familiarity with aroma, or smelling ability. Sample was small and limited to young university students. Aroma concentration and environmental conditions were not systematically monitored, and recordings came from consumer-grade EEG device.
Larger randomized study could compare coffee with both odor-free condition and another familiar scent while measuring participants’ coffee habits, preferences, and expectations. Until then, there is no reason to replace morning cup with five minutes of hopeful sniffing. But next time coffee improves your day before first sip, it may be worth wondering whether brain has already joined coffee break.
Study was published in Nutrients.
Q&A
Q: Can just smelling coffee change mood without drinking?
A: Japan study of 20 students found after 5 minutes beside brewed coffee, fatigue, tension anxiety, confusion, depression scores fell significantly even without caffeine intake.
Q: Does coffee aroma affect brain activity?
A: Researchers saw increase in EEG-derived relaxation index from alpha beta theta waves, but absolute increase modest and not correlated with mood changes individually.
Q: Does smelling coffee change heart rate?
A: No, heart rate and heart rate variability did not change significantly, suggesting mood and brain changes did not reflect coordinated body response.
FAQ
1. Where was coffee smelling mood study conducted?
Study conducted at Showa Pharmaceutical University in Japan, published in Nutrients, involving 20 university students aged 20-29 sitting 50cm from freshly brewed coffee.
2. How was coffee brewed for aroma test?
20 grams ground coffee with 400 ml water heated to 85°C in glass server placed 50 centimeters from participant for 5 minutes of normal breathing.
3. What mood changes were reported after coffee aroma?
Less fatigue, tension and anxiety, confusion, depression and dejection remained significant after statistical adjustment; vigor did not increase significantly.
4. Why might coffee smell improve mood before caffeine?
Smell linked to emotion and memory systems, plus learned associations morning warmth break promise of caffeine; 2018 study showed coffee-like scent raised performance expectations via placebo.
5. What are limitations of coffee aroma study?
No control odor-free room or other scent, no assessment of coffee drinking habits liking smelling ability, small young sample, aroma concentration not monitored, consumer-grade EEG.
