Table 3.

Selected key aromas in beer.

Selected alcohols	Concentration (mg/L)	Organoleptic description
Ethanol	20 000–80 000	Alcoholic, strong
1-Propanol	3–16	Alcoholic
2-Propanol	3–6	Alcoholic
2-Methylbutanol	8–30	Alcoholic, vinous, banana
3-Methylbutanol	30–70	Alcoholic, vinous, banana
2-Phenylethanol	8–35	Roses, bitter, perfumed
Selected esters	Concentration (mg/L)	Organoleptic description
Ethyl acetate	10–60	Solvent-like, sweet
3-Methylbutyl acetate (isoamyl acetate)	0.5–5.0	Banana, ester, solvent
Ethyl hexanoate	0.1–0.5	Apple, fruity, sweet
Ethyl octanoate	0.1–1.5	Apple, tropical fruit, sweet
2-Phenylethyl acetate	0.05–2.0	Roses, honey, apple, sweet
Selected aldehydes	Concentration (mg/L)	Organoleptic description
Acetaldehyde	2–20	Green, paint
Propanal	0.01–0.3	Green, fruity
Butanal	0.03–0.02	Melon, varnish
2-Methylpropanal	0.02–0.5	Banana, melon
trans-2-Butenal	0.003–0.02	Apple, almond
2-Methylpropanal	0.02–0.5	Banana, melon
Hexanal	0.003–0.07	Bitter, vinous
trans-2-Nonenal	0.00001–0.002	Cardboard
Furfural	0.01–1.0	Papery, husky
5-Methylfurfural	<0.01	Spicy
5-Hydroxymethylfurfural	0.1–20	Aldehyde, stale
Selected vicinal diketone	Concentration (mg/L)	Organoleptic description
2,3-Butanedione (diacetyl)	0.01–0.4	Butterscotch
3-Hydroxy-2-butanone (acetoin)	1–10	Fruity, mouldy, woody
2,3-Butanediol	50–150	Rubber, sweet, warming
2,3-Pentnedione	0.01–0.15	Butterscotch, fruity
3-Hydroxy-2-pentanedione	0.05–0.07
Terpens derived from hops	Concentration (ug/L)	Organoleptic description
Linalool	1–470	-
Citronellol	1–90	-
Geraniol	1–90	-
α-Terpineol	1–75	-
α-Eudesmol	1–100	-
Humulenol	1–1150	-
Clovanediol	51–677	-

Adapted from Baxter and Hughes, 2001. hyphen (-) no descriptor