Terpene Profiling in Beer
Application Note:
Identify and quantify 20 hop terpene compounds in a single 13-minute run.
Introduction
Hop terpenes define beer aroma. The balance of monoterpene hydrocarbons, sesquiterpenes, and sesquiterpene alcohols determines whether a beer carries citrus, pine, floral, or resinous character. GC-FID identifies and quantifies each compound independently, giving brewers a direct, compound-level terpene profile from a single analytical run.
The Challenge
Why terpene composition is difficult to track
Terpene composition varies between hop varieties, harvest years, and growing regions. It also changes during brewing. Terpenes are volatile, and the quantities that reach the finished beer depend on whirlpool temperature, dry-hop rate, contact time, and fermentation conditions.
Sensory evaluation can tell you whether hop character is present and at roughly what intensity. It cannot tell you which compounds are contributing, at what concentration, or whether a shift between batches reflects a change in the hops or a change in the process.
When two batches of the same recipe taste different, a terpene profile points directly to the cause. Without one, process correction is based on assumption.
The Solution
How GC-FID builds a hop terpene profile
The Ellutia 200 Series GC with FID detection resolves 20 terpene peaks from a 19-component hop terpene standard in a single 13-minute run. The method covers monoterpene hydrocarbons through to sesquiterpene alcohols, the full range of commercially relevant hop-derived terpenes.
Each compound is identified and quantified from a hexane extract of the beer sample. Results are available on-site from the same instrument used for ABV analysis and off-flavour detection.
Method Overview
How hop terpene analysis works
Beer samples are extracted with hexane before injection. The extract is transferred to a 2 mL vial and loaded into the instrument. No specialist equipment beyond standard laboratory solvents is required. If the sample contains visible particulate matter, filter before extraction.
Once injected, the extract passes through an EL-5 capillary column. The temperature programme separates the terpene compounds, with each eluting at a distinct retention time across the 13-minute run. The flame ionisation detector (FID) measures each peak as it exits the column, and the Ellution software calculates the concentration against the calibration.
Cis- and trans-nerolidol are supplied together in the standard but produce two resolved peaks under these conditions, giving 20 peaks from 19 compounds.
GC Conditions
- Column: EL-5, 30m × 0.25mm × 0.25μm
- Initial temperature: 40°C (2 min hold)
- Temperature ramp: 20°C/min to 200°C (hold 4 min)
- Injector temperature: 250°C
- Injection volume: 0.5 μL
- Split flow: 20 mL/min
- FID temperature: 300°C
Terpene Components
The method covers the 19 compounds listed below. Each is resolved as a separate peak under these GC conditions.
| # | Compound | # | Compound |
|---|---|---|---|
|
1
|
α-Pinene
|
11
|
α-Terpinolene
|
|
2
|
Camphene
|
12
|
Linalool
|
|
3
|
β-Pinene
|
13
|
Isopulegol
|
|
4
|
Myrcene
|
14
|
Geraniol
|
|
5
|
3-Carene
|
15
|
Trans-caryophyllene
|
|
6
|
α-Terpinene
|
16
|
α-Humulene
|
|
7
|
4-Isopropyltoluene
|
17
|
Nerolidol (trans)*
|
|
8
|
D-Limonene
|
18
|
Nerolidol (cis)*
|
|
9
|
3,7-Dimethyl-1,3,6-octatriene
|
19
|
Guaiol
|
|
10
|
γ-Terpinene
|
20
|
Bisabolol
|
*Nerolidol cis and trans elute as two separate peaks from a single component in the standard.
Results and Reliability
Calibration and and recovery data for hop terpene analysis
α-Pinene was used as the reference compound for calibration. A seven-point series from 1 to 250 ppm produced a straight-line fit with R² = 0.9976. Full recovery was confirmed across all 19 terpene compounds.
Beer samples were extracted and run through the same procedure. The method returned a clean baseline with no interfering peaks at the terpene retention times, confirming that beer matrix components do not obscure any of the 20 terpene peaks. Hop-forward samples will return quantitative compound-by-compound results from the same run.
Learn More
Get the full method and results
If you’d like to see the full details behind this testing method, you can download the complete application note. The application note includes the calibration curves, spike recovery results, and chromatograms for separation and spiked samples, along with the exact GC conditions used in the analysis.
Download the full application note.
The application note includes the calibration curves, spike recovery results, and chromatograms for separation and spiked samples, along with the exact GC conditions used in the analysis.
Frequently Asked Questions
-
What terpenes are found in hops?Hops contain a wide range of terpene compounds. The most analytically significant include α-pinene and β-pinene (pine character), myrcene (citrus and herbal), linalool (floral), trans-caryophyllene (spicy, woody), and α-humulene (earthy). The relative concentration of each varies significantly between hop varieties and harvest years.
-
Why do terpene levels change during brewing?Terpenes are volatile. They are lost during wort boiling, whirlpool resting, and fermentation. The quantities that reach the finished beer depend on addition timing, temperature, contact time, and yeast activity. Dry-hopping retains more terpenes than kettle addition because the process avoids high-temperature evaporation, but yields still vary by process.
-
How does GC-FID identify individual terpenes in beer?The beer sample is extracted with hexane. The extract is injected into the GC, where the EL-5 capillary column separates each compound by its physical and chemical properties. Each terpene elutes at a characteristic retention time and is measured by the FID as it exits the column. Concentrations are calculated against a calibration prepared from a known terpene standard.
-
Can the same instrument measure ABV and off-flavour compounds?Yes. The Ellutia 200 Series GC and EL-5 column used for this method can also run ABV analysis and terpene profiling using different oven programmes. See the [Complete Beer Profiling application note] for all three methods on a single instrument.