the library

Ale

Spirits & brews· beer

What it is

Ale is a beer brewed with top-fermenting yeast at warmer temperatures, from malted barley, water and hops.

What it tastes like

On the nose: dry, pear, almond. Among its measured molecules: 2,5-dimethylpyrazine, propanal, 1-butanol, 2-methyl-1-butanol, ethyl decanoate.

Every one of its 15 compounds carries a paper the library can cite.

• acetaldehydearomaaldehydereads as pungent, fruity (PubChem)Measured in 18 of 341 ingredients.cite

  1.83 to 5.25 mg/L across the five beers — a 2.9-fold strain effect, the HVK kveik culture leaving less than half what the others do — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Acetaldehyde', all five beer columns)
• 1-butanolaromaalcoholreads as dry, burning taste (PubChem)Measured in 13 of 341 ingredients.cite

  0.25 to 0.61 mg/L across the five beers, the VK2 fermentation making less than half what the others do — Kawa-Rygielska et al. 2022, Molecules (Table 4, row '1-butanol', all five beer columns)
• propanalaromaaldehydereads as similar to acetaldehyde (PubChem)Measured in 11 of 341 ingredients.cite

  0.43 to 0.73 mg/L across the five beers. The FM-53 cell is printed with a comma decimal separator, '0,69 ± 0.01', in a table that otherwise uses points; it is read as 0.69 mg/L. — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Propanal', all five beer columns)
• 1-propanolaromaalcoholreads as burning taste (PubChem)Measured in 23 of 341 ingredients.cite

  28.70 to 70.22 mg/L across the five beers — a 2.4-fold strain effect, the largest relative spread of any compound present in all five, with VK2 more than double every other yeast — Kawa-Rygielska et al. 2022, Molecules (Table 4, row '1-propanol', all five beer columns)
• phenylethyl alcoholaromaalcoholreads as sharp burning taste (PubChem)Measured in 42 of 341 ingredients.cite

  29.27 to 55.68 mg/L across the five beers — the widest strain effect of any of the large alcohols, the FM-53 fermentation making nearly twice what VK2 does — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Phenylethyl alcohol', all five beer columns)
• isobutanolaromaalcoholreads as sweet, musty (PubChem)Measured in 24 of 341 ingredients.cite

  38.41 to 56.97 mg/L across the five beers; the VK2 fermentation makes about 48% more of it than the lowest — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Isobutanol', all five beer columns)
• furfuralaromafuranreads as almond (PubChem)Measured in 34 of 341 ingredients.cite

  5.65 to 9.19 mg/L across the five beers. Worth reading against the stout node, whose furfural range (from the same research group's later paired dark/pale study, cited there) overlaps this one: furfural is not a dark-beer compound, it is a beer compound, and this pale NEIPA carries as much of it as a roasted-malt beer does. The comparison figures live in stout.json, on the paper that measured them. — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Furfural', all five beer columns)
• ethyl octanoatearomaesterMeasured in 24 of 341 ingredients.cite

  0.80 to 1.01 mg/L across the five beers — a 26% spread, one of the most yeast-independent compounds in the table — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Ethyl octanoate', all five beer columns)
• ethyl decanoatearomaesterMeasured in 17 of 341 ingredients.cite

  3.31 to 12.16 mg/L across the five beers — a 3.7-fold strain effect and the largest of the ethyl esters, with the US-05 control making by far the least of it — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Ethyl decanoate', all five beer columns)
• 2-methyl-1-butanolaromaalcoholMeasured in 15 of 341 ingredients.cite

  28.09 to 35.38 mg/L across the five beers — a narrow 26% spread, the most yeast-independent of the higher alcohols and therefore the most category-typical — Kawa-Rygielska et al. 2022, Molecules (Table 4, row '2-methylbutanol', all five beer columns)
• ethyl acetatearomaesterreads as fragrant (PubChem)Measured in 43 of 341 ingredients.cite

  95.95 to 120.86 mg/L across the five NEIPA beers — the largest single volatile in every one of them and roughly a quarter of each beer's stated total volatiles. Highest in the US-05 control, lowest in FM-53. — Kawa-Rygielska et al. 2022, Molecules (Table 4 (Analysis of volatile compounds of the beers), row 'Ethyl acetate', all five beer columns)
• 2,5-dimethylpyrazinearomapyrazineMeasured in 10 of 341 ingredients.cite

  0.80 to 1.21 mg/L across the five beers. A Maillard pyrazine quantified in a pale, hop-forward ale — not a roast beer — which is the least expected result in this table and is reported here because the paper measured it in every one of the five. — Kawa-Rygielska et al. 2022, Molecules (Table 4, row '2,5-dimethylpyrazine', all five beer columns)
• isoamyl alcoholaromaalcoholMeasured in 46 of 341 ingredients.cite

  86.59 to 124.70 mg/L across the five beers — the largest higher alcohol in every one and the second-largest volatile overall. The VK2 beer is the outlier at 86.59 mg/L against 115-125 mg/L for the other four. — Kawa-Rygielska et al. 2022, Molecules (Table 4, row '3-methylbutanol', all five beer columns)
• ethyl hexanoatearomaesterMeasured in 36 of 341 ingredients.cite

  0.30 to 0.44 mg/L across the five beers — the smallest ester quantified in all five, and a compound whose concentration in this ale is roughly a thousandth of ethyl acetate's in the same glass — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Ethyl hexanoate', all five beer columns)
• isoamyl acetatearomaesterreads as pear (PubChem)Measured in 26 of 341 ingredients.cite

  0.51 to 0.67 mg/L across the five beers, and the paper's own letters make every one of the five significantly different from every other — the most finely strain-discriminated compound in the table despite the narrow absolute range — Kawa-Rygielska et al. 2022, Molecules (Table 4, row 'Isopentyl acetate', all five beer columns)