Compounds · Esters · Microbial origin
Ethyl butanoate
Also known as Ethyl butyrate · Pineapple ester — an analysis may use any of these names
Pineapple, banana, fruit sweets. The molecule of fruit that is just ripe, and of fruit that is overripe.
- CAS
- 105-54-4
- Formula
- C6H12O2
- Molar mass
- 116.16
- Odour threshold
- 1 ppbin water
- Boiling point
- ≈ 121 °C at atmospheric pressure
This compound boils at 121 °C, so it is lighter than any ordinary essential-oil component. It lies outside the 150–290 °C band, so the marker stops at the left edge — not because that is where it sits, but because the axis does not reach that far.
The two axes are 47 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: Microbial origin — made by bacteria and yeasts, not by plants.
Ethanol, acetic acid and fruity esters are all made by yeasts and bacteria, but the raw material is the plant’s sugar. The microbial pathway is almost always a second layer placed on top of what the plant has made.
About the threshold figure
Low. Fruity esters generally have low thresholds — which is why ripe fruit smells clearly even though the amount of these compounds is very small.
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 small ester of only six carbons, very light and gone almost instantly. It lies outside the usual volatility band of essential oils.
Where else you meet it
Pineapple, banana, ripe jackfruit, fermented sticky rice, and most artificial fruit flavours.