2,4,5-trimethylthiazole

sulfurous thiazole

Found in 16 ingredients across the CompKitchen flavor graph.

Look up another compound — search by name, CAS number, PubChem CID, or FEMA #.

2D Lewis Structure

Formula: C6H9NS
Molecular weight: 127.21 g/mol
PubChem CID: 61653 — full record on PubChem

Properties

Odor description: earth
Odor threshold — orthonasal, in clean water: 50.0 ppb 2 published values · see all 2 with sources
Volatility: high
CAS number: 13623-11-5
Retention index: 1387

Regulatory · United States

FEMA GRAS — Generally Recognized As Safe for flavoring use

✓ Exact match

FEMA number: 3325
GRAS publication: GRAS 5
FEMA primary name: 2,4,5-Trimethylthiazole

Use-level matrix not extracted for this substance — check the source publication for current ppm guidance.

Source: FEMA GRAS publications 1-33.

How this molecule is described

Sources disagree about odour more often than they disagree about chemistry. Rather than show one answer, here is every description on file with how many ingredient records carry it.

Also filed as

2,4,5-trimethyl-thiazole

Same molecule, unified here — previously counted and displayed as separate compounds.

Descriptions on file

Ordered by how many independent descriptor streams give each wording, then by how often it appears. The bar is still replication — one source copied onto many ingredients scores high there — so the two can disagree.

earth shown above Flavornet Cas

—

chocolate, cocoa, coffee, earth, hazelnut, musty, nutty, vegetable FlavorDB 2.0

Bars are the share of ingredient records carrying each description. High agreement means the sources replicate each other — not necessarily that they are right.

Published thresholds

2 measured values from the literature. Grouped by what was actually measured — a threshold smelled in clean water, tasted in the mouth, or measured in a real food are three different quantities and are not pooled.

Orthonasal, in clean water

50.0 ppb

The reference measurement — smelled in water. OAV is computed against this.

Threshold	Matrix	Source	Paper
50.0 ppb	water_odor	Leffingwell	—
50.0 ppb SIDA	water	Rychlik 1998 · 1 studies	—

Only values we can attribute are listed. Where a compendium's licence does not permit public attribution its figures are omitted here, so every number on this page traces to a citable source.

Thresholds in published tables

Numbers printed in open-access papers, grouped by the medium the table states. Median and full range of the values; “agree” means two or more papers whose middle 80% of values sit within 100×. Not reviewed.

Medium	Median	Range	Values	Papers	Papers agree?
air	45 µg/L air	45–45	1	1	one paper
food matrix	50 ppb	50–50	1	1	one paper
oil	50 ppb	50–50	1	1	one paper
unstated	2.248 ppb	0.002–1e+03	6	3	no (3.2 decades)

Found in

Measured impact first, then profile share

Every ingredient known to contain 2,4,5-trimethylthiazole. Ingredients with a measured concentration come first, ranked by odour activity; the rest follow by how large a share of that ingredient's profile this molecule is. The figure beside each is how many different compounds that ingredient has in total — not the concentration of 2,4,5-trimethylthiazole in it.

59 cmpds

66 cmpds

99 cmpds

106 cmpds