Alpha acids tell you how bitter a hop can make your beer. Essential oils tell you what the beer will smell like — and for most modern recipes that is the harder, more interesting question. A hop cone is roughly 0.5–4.5 ml of oil per 100 g of dry matter, which sounds trivial until you realise that this fraction of a percent by weight carries almost the entire aromatic identity of the variety.
This article breaks the oil fraction into the compounds that actually matter at the brewhouse scale: myrcene, humulene, caryophyllene, farnesene and the oxygenated minority led by linalool and geraniol. Every number below is either a measured varietal range or a percentile from the 329-variety Hopedia corpus, so you can see where your hop sits rather than guessing.
Total oil: the number to read first
Before you look at composition, look at volume. Across the Hopedia database (n=279 varieties with oil data) the median total oil is 1.5 ml/100 g, with the 25th percentile at 1.1, the 75th at 2.0 and the 90th at 2.6 ml. The extremes run from 0.5 ml (many old landrace aroma hops) to 4.5 ml.
That distribution has a direct practical consequence: a hop at 2.6 ml/100 g delivers roughly 2.4× the aroma payload per gram of a hop at 1.1 ml/100 g. If a recipe calls for 8 g/L of dry hops of a high-oil variety and you substitute something in the bottom quartile, you are not making a "similar" beer — you are making a beer with less than half the aromatic mass. Scale by oil, not by weight.
Worth noting: total oil correlates loosely with alpha acids because both accumulate in the lupulin gland. High-alpha American varieties cluster in the upper half of the oil distribution. Columbus is the clearest case in this set — 2.5–4.5 ml/100 g puts its upper end at the absolute maximum of the corpus, and even its lower bound of 2.5 ml sits near the 90th percentile.
Myrcene: the volatile, fruity, fragile one
Myrcene is a monoterpene and almost always the largest single component. In the corpus it averages 42.4% of total oil (median 42.3%, p25 32.5%, p75 51.8%, range 3–70%). It smells green, resinous, citrus-peel, "fresh hop" — and it is the compound responsible for the smell of a freshly opened vacuum bag.
Two properties dominate how you use it:
- It is highly volatile. A 60-minute boil destroys or strips the overwhelming majority of myrcene. Anything you want from myrcene must go in at flameout, whirlpool below ~80 °C, or into the fermenter.
- It is poorly water-soluble and oxidises fast. Myrcene-dominant hops lose character in storage faster than humulene-dominant ones. Buy them fresh, keep them at −18 °C, and use the bag within weeks of opening.
Citra is the textbook high-myrcene hop at 60–70% of oil. That upper bound is the corpus maximum, and even the low end sits at the 90th percentile. Combined with 1.5–3 ml total oil, a 70% myrcene fraction means a gram of Citra can deliver ~2.1 mg of myrcene — several times what a noble hop manages. This is exactly why Citra reads as loud, immediate, juicy, and why it fades so noticeably in a keg after two months.
Citra sits well above the corpus median for myrcene while Saaz sits well below it, and the oil profiles diverge in exactly the way their aromas suggest.
| — | Citra | Saaz (CZ) | Columbus |
|---|---|---|---|
| Total oil | 1.5–3 ml | 0.4–1 ml | 2.5–4.5 ml |
| Myrcene | 60–70% | 25–40% | 45–55% |
| Caryophyllene | 5–8% | 6–9% | 6–10% |
| Humulene | 7–13% | 15–30% | 9–14% |
| Farnesene | 0–1% | 14–20% | 0–1% |
Practical myrcene dosing
For whirlpool additions, 2–4 g/L at 75–80 °C for 15–20 minutes retains a useful share of myrcene while still allowing some isomerisation. Above 85 °C you lose a disproportionate amount. For dry hopping, 4–8 g/L in a standard IPA and 8–12 g/L in a hazy is where myrcene-forward varieties shine; beyond ~12 g/L you mostly buy vegetal grassiness and hop creep, not more fruit.
Humulene: noble, spicy, and surprisingly boil-tolerant
Humulene is a sesquiterpene — heavier, less volatile, and much more interesting in the kettle. The corpus median is 18.5% of oil (p25 12.5%, p75 25.1%, p90 35.7%, max 57%). Humulene itself smells woody and faintly herbal, but its real contribution comes from its oxidation products: humulene epoxides and humulenol, which read as noble, spicy, tobacco-like, cedar. These form during kilning, storage and boiling — meaning a late-boil humulene addition (say 10–15 minutes) can genuinely improve a Pilsner in a way it never could for myrcene.
Tettnanger at 20–21% humulene and Saaz (CZ) at 15–30% are the reference points. Note that Saaz's ratio matters more than its absolute numbers: with only 0.4–1 ml total oil (bottom quartile of the corpus, and the lower bound close to the corpus minimum), Saaz is not delivering much oil mass at all — it is delivering a very particular balance. The famous humulene-to-caryophyllene ratio of the noble hops runs roughly 3:1 to 4:1; American dual-purpose hops typically sit nearer 1:1 to 1.5:1.
| Variety | Total oil (ml/100 g) | Myrcene | Humulene | Caryophyllene | H:C ratio |
|---|---|---|---|---|---|
| Citra | 1.5–3.0 | 60–70% | 7–13% | 5–8% | ~1.5:1 |
| Columbus | 2.5–4.5 | 45–55% | 9–14% | 6–10% | ~1.4:1 |
| Mosaic | 1.0–1.5 | 47–55% | 10–16% | 3–8% | ~2.4:1 |
| Simcoe | 0.8–3.2 | 40–50% | 15–20% | 8–14% | ~1.6:1 |
| Tettnanger | 0.4–1.1 | 40–41% | 20–21% | 6–7% | ~3.2:1 |
| Saaz (CZ) | 0.4–1.0 | 25–40% | 15–30% | 6–9% | ~3.0:1 |
| Corpus median | 1.5 | 42.3% | 18.5% | 8.5% | ~2.2:1 |
Caryophyllene: pepper, wood and the spice backbone
Beta-caryophyllene is the other major sesquiterpene, with a corpus median of 8.5% of oil (p10 4.5%, p90 13.5%, max 29%). It smells peppery, woody, slightly dry-herbal, and — unlike myrcene — it survives the boil reasonably well and contributes to that clean spicy edge in German and Czech lagers as well as to the "dank" side of American hops.
Simcoe at 8–14% caryophyllene sits from the median up to the 90th percentile, and that is a large part of why Simcoe reads as piney and resinous rather than purely fruity — the sesquiterpene fraction (15–20% humulene plus 8–14% caryophyllene, so 23–34% of oil) is unusually heavy for an American aroma hop.
Practically: caryophyllene-rich hops tolerate 10–20 minute boil additions and even respond well to first-wort hopping. If your Pilsner tastes flat and one-dimensional, adding 0.5–1 g/L of a caryophyllene/humulene hop at 15 minutes does more than doubling the whirlpool.
Farnesene: the rarest marker in the database
Farnesene is the single most skewed compound in the corpus, and it is the clearest example of what cross-database statistics can tell you that a single hop page cannot. The median farnesene is 0.5% of oil, the 25th percentile is also 0.5%, and the 75th percentile is 4% — meaning more than half of all 329 varieties are effectively farnesene-free. Yet the maximum reaches 26%.
That makes farnesene a near-binary trait. Tettnanger at 11–12% and Saaz at 14–20% both sit above the 90th percentile (9.5%); Saaz's upper bound is in the top handful of varieties in the entire database. Meanwhile Citra, Mosaic, Simcoe and Columbus are all at 0–1% — below the corpus median. Farnesene contributes a green-apple, linden-blossom, faintly waxy floral note, and its presence or absence is probably the most reliable single chemical fingerprint separating continental European landrace hops from American breeding lines. If a recipe specifically wants that soft floral lift, no amount of Citra will substitute for it.
The three hops below differ far more in farnesene than in any other terpene, which is why Saaz and Tettnanger smell "European" and Mosaic does not.
| — | Saaz (CZ) | Tettnanger | Mosaic |
|---|---|---|---|
| Total oil | 0.4–1 ml | 0.4–1.1 ml | 1–1.5 ml |
| Myrcene | 25–40% | 40–41% | 47–55% |
| Caryophyllene | 6–9% | 6–7% | 3–8% |
| Humulene | 15–30% | 20–21% | 10–16% |
| Farnesene | 14–20% | 11–12% | 0–1% |
Linalool, geraniol and the oxygenated fraction
Here is the twist: the four hydrocarbons above make up 80–95% of hop oil, but they are poorly water-soluble and much of them never reaches your glass. The oxygenated fraction — typically 5–20% of total oil — punches far above its weight because these compounds are polar, soluble in beer and have extremely low flavour thresholds.
- Linalool — floral, coriander-citrus, lavender. Flavour threshold around 8–80 µg/L depending on matrix; typical dry-hopped pale ales measure 20–200 µg/L. Linalool is the best single chemical correlate of perceived "hoppiness" in finished beer, and it survives fermentation reasonably well.
- Geraniol — rose, geranium, sweet citrus. Threshold roughly 4–36 µg/L. Critically, many ale yeasts biotransform geraniol into β-citronellol (lime, citrus peel) during active fermentation, which is the whole mechanism behind dry hopping on day 2–3 of fermentation rather than after.
- Humulene and caryophyllene epoxides — the noble/spicy oxidation products discussed above.
- Thiols (3MH, 3S4MP) — not oils at all but polyfunctional sulfur compounds, at ng/L thresholds, responsible for passionfruit and guava in varieties like Citra and Mosaic. They are often bound as cysteine/glutathione conjugates in the cone and released by yeast β-lyase activity.
Because oxygenated compounds are the soluble ones, cold-side contact is disproportionately efficient. Dry hopping at 18–20 °C extracts noticeably more linalool and geraniol than dry hopping at 2 °C; a 24–48 hour warm contact is usually enough, and pushing to 5–7 days mainly adds polyphenol grip and hop creep risk.
Turning oil data into recipe decisions
Rules of thumb
- Myrcene > 55% of oil (top ~15% of the corpus): treat as a cold-side hop only. Flameout, whirlpool ≤80 °C, dry hop. Expect fast fade.
- Humulene > 25% (top quartile) with H:C above 2.5:1: usable at 10–20 minutes in the boil; rewards late-kettle rather than dry hopping.
- Total oil < 1.1 ml (bottom quartile): plan on 1.5–2× the gram dosage of a modern high-oil variety for comparable intensity, and accept a different character rather than the same one.
- Total oil > 2.6 ml (top decile): 4–6 g/L dry hop is often plenty; over-dosing produces harsh, onion-garlic or vegetal notes.
A worked dosage comparison
The table below normalises dosage by approximate oil mass delivered, using midpoint oil values. It is the single most useful calculation you can do when substituting hops.
| Variety | Mid total oil | Dose for ~12 mg oil/L | Best use window |
|---|---|---|---|
| Columbus | 3.5 ml/100 g | ~3.4 g/L | Bittering, 20 min, modest dry hop |
| Citra | 2.25 ml/100 g | ~5.3 g/L | Whirlpool + dry hop |
| Simcoe | 2.0 ml/100 g | ~6.0 g/L | Whirlpool, dry hop, late boil |
| Mosaic | 1.25 ml/100 g | ~9.6 g/L | Dry hop dominant |
| Tettnanger | 0.75 ml/100 g | ~16 g/L (impractical) | 10–20 min boil, 1–3 g/L |
| Saaz (CZ) | 0.7 ml/100 g | ~17 g/L (impractical) | Late boil / 3–5 g/L cold |
The point of the last two rows is not that you should dose 16 g/L of Tettnanger — it is that noble hops are never trying to compete on oil mass. Their job is a specific ratio delivered at low intensity. Treat them as seasoning, and treat Mosaic or Citra as the main ingredient.
If you remember one thing: myrcene is what a hop smells like in the bag, humulene and caryophyllene are what survives the kettle, and linalool and geraniol are what actually ends up dissolved in the beer.
Storage: the number nobody checks
Oil loss during storage is not uniform. Myrcene degrades fastest; after 6 months at room temperature a myrcene-dominant pellet can lose 40–60% of its myrcene while humulene declines much less and its epoxides increase. The practical result is that a stale high-myrcene hop does not smell like a weaker version of itself — it smells like a different hop, more cheesy, woody and spicy. Vacuum packing plus −18 °C storage keeps oil losses in the single-digit percent range per year. For any variety above the 75th percentile in myrcene, that is not optional.