Measuring the Scoville Heat Units of Chilli-Infused Olive Oil
Many chilli products make bold claims about the peppers they contain, but how much heat actually makes its way into the final product? In this article, we'll examine a chilli-infused olive oil containing sun-dried tomatoes and chilli, and demonstrate how the FoodSense Generation 4 system can be used to estimate its Scoville Heat Units (SHU).
Unlike traditional chilli sauces or powders, infused oils present a unique analytical challenge because oil-based samples do not readily mix with the aqueous solutions typically used during capsaicin analysis. To overcome this, a simple pre-preparation step is required.
The Challenge of Testing Chilli Oils
Most FoodSense chilli testing procedures involve taking a small amount of sample and diluting it directly into the supplied buffer solution. This works well for aqueous and semi-solid samples.
Olive oil, however, is highly hydrophobic and lipophilic, meaning it does not mix effectively with water-based solutions. Without suitable preparation, it can be difficult to obtain a representative measurement of capsaicin concentration.
To address this issue, a pre-preparation solvent is used to help the chilli-infused oil mix more effectively with the analysis buffer.
Sample Preparation
The first step is to prepare the oil sample.
A measured volume of:
1 mL chilli-infused olive oil
1 mL pre-preparation solvent
is combined and mixed thoroughly.
This initial step creates a 1-in-2 dilution and improves compatibility between the oil and the aqueous analysis system.
Once mixed, the sample can be treated much like a standard chilli sample.
Creating the Test Dilution
From the prepared mixture:
100 µL is transferred into a sampling tube
900 µL of FoodSense buffer is added
This creates an additional 1-in-10 dilution.
Combined with the earlier 1-in-2 pre-preparation step, the total dilution factor becomes:
1 in 20
This dilution factor must be considered when calculating the final Scoville result.
Mixing and Sensor Analysis
To ensure complete homogenisation, the sample is vortex mixed before analysis.
Modern FoodSense workflows strongly recommend the use of a vortex mixer because it significantly improves mixing consistency, particularly when working with oil-containing samples.
After mixing:
50 µL of the diluted sample is applied to a FoodSense chilli sensor
The test is run through the FoodSense application
The sensor detects capsaicin and related compounds
The software calculates an estimated Scoville Heat Unit value
The Result
The FoodSense app reported a value of:
1,860 SHU
However, this result only reflects the diluted sample submitted to the sensor.
Because the sample underwent an additional 1-in-2 dilution during pre-preparation, the result must be multiplied by two.
Corrected Result
1,860 × 2 = 3,720 SHU
Therefore, the estimated heat level of this chilli-infused olive oil is:
Approximately 3,720 Scoville Heat Units
How Hot Is 3,720 SHU?
A value of around 3,700 SHU places this product in a similar heat range to Tabasco sauce.
Although the product may reference very hot chilli varieties such as Carolina Reaper peppers, the measured heat level indicates that only a relatively small amount of capsaicin has been transferred into the oil.
This is not unusual. The heat level of an infused oil depends on numerous factors, including:
The quantity of chilli used
Extraction efficiency
Infusion duration
Processing conditions
Final dilution within the oil
As a result, the presence of an extremely hot chilli variety does not necessarily mean the finished product will exhibit extreme heat levels.
Sensory Verification
Following the instrumental measurement, a small taste test confirmed that the result appeared realistic.
The oil delivered a noticeable warmth and a slight throat kick, but it was not overwhelmingly hot. Subjectively, the sensation aligned closely with the measured value and supported the comparison to Tabasco-style heat levels.
While sensory testing should never replace quantitative measurement, it can provide useful context when evaluating analytical results.
Testing Unusual Chilli Products
One of the strengths of the FoodSense Generation 4 platform is its flexibility when analysing non-standard chilli products.
Although there is no official standard method for determining the Scoville Heat Units of chilli-infused olive oils, a straightforward sample preparation procedure can produce meaningful and repeatable estimates of capsaicin concentration.
With the correct pre-preparation and dilution strategy, products such as:
Chilli oils
Infused oils
Marinades
Condiments
Complex food matrices
can all be analysed using the FoodSense system.
Conclusion
This chilli-infused olive oil produced a corrected measurement of approximately 3,720 Scoville Heat Units, placing it in a heat range comparable to Tabasco sauce.
The test also demonstrates an important analytical principle: when working with oil-based products, proper sample preparation is essential to obtain reliable capsaicin measurements. By using a simple pre-preparation step and accounting for dilution factors, FoodSense Generation 4 can successfully analyse unusual chilli-containing products that would otherwise be difficult to test.
If you have questions about measuring capsaicin in challenging or unconventional sample types, the FoodSense team is always happy to help.
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