Compounds · Aldehydes · Heat (Maillard reaction and pyrolysis)
Furfural
Also known as 2-Furaldehyde · Fural — an analysis may use any of these names
Almond, burnt bread, with a slight wood note. Dry sweetness.
- CAS
- 98-01-1
- Formula
- C5H4O2
- Molar mass
- 96.08
- Odour threshold
- 3.0 ppmin water
- Boiling point
- ≈ 162 °C at atmospheric pressure
The two axes are 75 points apart. Volatility tells you whether the compound leaves a surface early or late; the threshold tells you how much of it the nose needs before it notices. When the two sit this far apart, they explain things the percentages on an analysis cannot explain on their own.
Where it comes from
Biosynthetic pathway: Heat (Maillard reaction and pyrolysis) — fire breaks large molecules into ones you can smell.
About the threshold figure
High. It is abundant in baked and roasted foods but contributes modestly to smell for its quantity.
Published thresholds differ by several orders of magnitude, because of differences in measuring method, sample purity and panel. The figure here is an order of magnitude for relative comparison, not a measurement. We give it only for compounds where the literature broadly agrees — 52 of the 106 compounds in the library. The rest are left blank rather than guessed.
Why it sits where it does
A five-membered furan ring carrying an aldehyde group — a small but polar molecule, so it boils at around 162 degrees.
Where else you meet it
Straw smoke, roasted coffee, caramelised sugar, and spirits aged in wooden barrels.