Key odorant · the claim says “primary odorants of wheat bread crust”
A review of bread aroma chemistry reports 2-acetyl-1-pyrroline, (E)-2-nonenal, 3-methylbutanal, 2,3-butanedione, methional and (Z)-2-nonenal as primary odorants of wheat bread crust, with 2-acetyl-1-pyrroline suggested as the key crust odorant behind its cracker-like note; the crumb has a different set, and these odorants are generated mainly during baking.
Scope: Wheat bread; crust and crumb differ, and odorants depend on ingredients, fermentation and baking. CLM-BREAD-001 ↗
Reported volatile · the claim says “alongside compounds such as”
A gas chromatography–olfactometry study of condensed mixed-hardwood smoke found phenolic compounds such as guaiacol, 4-methylguaiacol and 4-methylsyringol among its most potent odorants, alongside compounds such as 2,3-butanedione.
Scope: Supports the odorants of one condensed hardwood smoke studied for food smoking; open fires, other woods and burning conditions can differ. CLM-WOODSMOKE-001 ↗
Key odorant · the claim says “the key odorants of sour cream butter”
A review of aroma studies reports that sweet cream butter is characterised by lactones and sulfur compounds, while the key odorants of sour cream butter are diacetyl, butanoic acid and δ-decalactone, formed mainly by lactic acid bacteria.
Scope: Key odorants differ between sweet cream, sour cream and heated butter and butter oil. CLM-BUTTER-001 ↗
Key odorant · the claim says “contribute importantly to the aroma”
Recombination and omission experiments showed seven compounds contribute importantly to the aroma of an aged Chinese cereal vinegar: 2,3-butanedione, acetic acid, 2-methylpropanal, sotolon, 2,4,5-trimethyloxazole, 3-methylbutanoic acid and tetramethylpyrazine.
Scope: One traditional aged cereal vinegar; fruit, wine and distilled vinegars differ. CLM-VINEGAR-001 ↗
Checked against PubChem and Wikidata on 2026-10-02 (identifier check run 37063263965). Every name SmellBook uses must resolve to the same single PubChem compound.
WHAT THIS MEANS
SmellBook lists a molecule only where a VERIFIED claim names it, in the role and scope that claim states. A molecule reported in a smell's evidence is not the whole smell: most smells come from many compounds together, and the studies measured particular samples, such as one cultivar, an essential oil or a cooked product.