Printed from smellbook.com/smells/hay. This printout keeps the entry for Hay itself: its description, reference card, Connections, questions, evidence, related smells, record details, states, names and citation. It leaves out your own notes, the map, the lists of paths, routes, stories and fragrance directions, and the lists headed “Also linked to” (other entries that share its place or material) and “Linked from”; they are on the page online. The entries this one links to are still printed under Connections and Related smells.
Categories and types group entries for browsing; they are editorial, not evidence. How smells are grouped.
Hay
Dry grassy warmth with sweet, dusty and sun-warmed field associations.
Its type, Source, means the smell is named after “a physical origin that can contribute a smell”; it is not an evidence source, such as a study or a book.
Links SmellBook records for this entry: where you meet it, what was written about it, molecules and related smells. EDITORIAL links are chosen by SmellBook editors, VERIFIED links come from VERIFIED claims and HISTORICAL links describe what one source wrote at one time. Nothing here is a ranking, and a molecule is not presented as the cause of the smell.
QUESTIONS ABOUT HAY
Hay, question by question
What does hay smell like? EDITORIAL
Hay smells dry, grassy and warm, with a sweet, sun-baked note that some compare to tea leaves or tobacco. A fine dustiness rises when it is shaken, giving the nose a tickly, dry texture. Freshly baled hay is greener and sweeter; older hay turns flatter and more dusty. It is often confused with straw, which is paler, thinner and less sweet.
It is met in barns and stables, in fields after mowing, and along country lanes beside freshly baled fields. Pet bedding, rabbit hutches and decorative bales carry a milder version indoors.
One VERIFIED scientific claim from one published source is recorded for this entry: Volatiles released as cut grass dries. This claim says only what its source supports, in the scope shown with it.
The scientific study behind this evidence is chemistry or emission work, not a study of how the smell is perceived.
It also has one historical source, which records what was written without stating the time described, not a scientific finding: see its historical records.
6 molecules are named in this claim; see the evidence for the role the claim gives them. The molecules this claim names were detected or measured in the study. The claim does not say they shape the smell.
How do people describe it, and what is it compared with? EDITORIAL
Hay represents dried plant material and differs from the vivid green smell of freshly cut grass.
One historical source describes it. It describes a time it does not state, no later than its publication, not the present: see its date in Connections; the sources are with the evidence below.
What is not known yet?
Why it smells as it does: none of its VERIFIED claims says what produces the smell.
Answers marked EDITORIAL are written by SmellBook editors to describe the experience and add no scientific fact. Answers marked VERIFIED point to claims on published sources, checked against each source's own summary where one was available (each claim's page says how); what each claim supports is in its own text and scope.
01WHAT THE EVIDENCE SAYSVERIFIED
What the evidence supports
This one VERIFIED scientific claim, from one source, covers the chemistry reported and the conditions or places studied. How the scientific evidence was produced: emissions or air measured. One historical source records what was written without stating the time described (“Coumarin and good hay in 1911”); it is not a scientific finding or a scientific explanation of why it smells. Each claim says only what its source supports, in the scope shown with it.
What is editorial
The description, smell words, associations and related smells on this page are written by SmellBook's editors and labelled EDITORIAL or CULTURAL; a claim below does not make them VERIFIED.
In laboratory measurements, cut grass and clover released a burst of volatile compounds when cut, followed by a second, more intense emission lasting several hours as the plants began to dry, with enhanced emissions of methanol, acetaldehyde, acetone and butanone besides the (Z)-3-hexenal,(Z)-3-hexenol and hexenyl acetate released on wounding.
Freshly cut grass and clover drying in a laboratory; the source does not mention haymaking or study finished hay, and it measures emissions, not odour.
Also covers: chemistry reported (the claim names compounds or kinds of compounds).
How this was found: Emissions or air measured. What a material, product or place releases into the air was measured, usually without assessing odour. Source: primary study; material-emission work.
The 1911 Encyclopædia Britannica's article on hay as fodder says good hay should come out green and smelling of coumarin, the substance it credits with the scent of new-mown hay.
A reference work describing hay quality in its own time; SmellBook records what it says, not a present-day analysis of hay.
How this was found: Historical text. A published historical text, read on a digitised page; it records what was written when it was published. Source: historical record.
Passage: p. 109. Published 1911, the latest time it can describe; not the present.
Each step is a relationship SmellBook editors recorded in the knowledge graph, named as it is published there. Paths are not ranked or personalised, and they do not mean the smells smell alike.
Each step is a molecule that a VERIFIED claim names for both smells, in whatever role the claims state. Sharing a molecule does not mean two smells smell alike.
CULTURAL: This entry's associations depend on context, language, memory or culture; its description and smell words are editorial. It says nothing about research or historical evidence; evidence for this entry is shown separately: VERIFIED.
ATLAS POSITION062 / 200
MILESTONEIconic 100
PRIMARY CATEGORYNature
PUBLIC TYPESource
PROFILE STATUScomplete
States recorded for Hay
dryEDITORIALThe entry records a setting in this state. (“dry grass”)Dry vs Wet
A state says how an entry is met, such as wet, aged or roasted. It does not create a new smell, and it adds no scientific fact by itself: states marked EDITORIAL come from the entry's own records, and only those marked VERIFIED are reported by a VERIFIED claim.
Names and identity for Hay
How this entry is identified and named, for citing it or matching it with other records.
SmellBook. (2026). Hay (revision 3, 2026-10-06). SmellBook Public Atlas. smellbook:smell:hay. https://smellbook.com/smells/hay
BibTeX and RIS for reference managers
@misc{smellbook_hay_r3,
author = {{SmellBook}},
title = {Hay},
year = {2026},
note = {SmellBook Public Atlas, revision 3, 2026-10-06, smellbook:smell:hay},
url = {https://smellbook.com/smells/hay}
}
TY - ENCYC
ID - smellbook-hay-r3
TI - Hay
AU - SmellBook
T2 - SmellBook Public Atlas
PY - 2026
DA - 2026/10/06
ET - revision 3
UR - https://smellbook.com/smells/hay
N1 - SB-0062; smellbook:smell:hay; resolver https://smellbook.com/id/smell/hay
ER -
The citation names revision 3 of 2026-10-06, so a reader can tell exactly which version was cited. Citing records what was read; it does not grant a licence.
PROFILE NOTE
Hay represents dried plant material and differs from the vivid green smell of freshly cut grass.