Fat and moisture content are critical measurements for both California olive growers and olive oil processors. Growers are typically paid based on the fat and moisture content of each load of olives, while processors use this information to evaluate harvest timing, oil extraction efficiency, and overall quality. Because different laboratories and processors use different equipment and testing methods, results can sometimes vary.
To improve consistency across the California olive oil industry, the UC Davis Olive Center partnered with the Olive Oil Commission of California (OOCC) to establish the Annual Ring Test beginning with the 2022/23 season. The program compares results from participating laboratories using standardized samples to evaluate testing consistency and improve measurement accuracy across the industry. The program continues to evolve each year to strengthen confidence in fat and moisture testing statewide
To improve consistency across the California olive oil industry, the UC Davis Olive Center partnered with the Olive Oil Commission of California (OOCC) to establish the Annual Ring Test beginning with the 2022/23 season. The program compares results from participating laboratories using standardized samples to evaluate testing consistency and improve measurement accuracy across the industry. The program continues to evolve each year to strengthen confidence in fat and moisture testing statewide
2025/2026 Ring Test
In the 2025/26 season, a total of 11 olive samples were analyzed over three testing rounds. 80% of the official method labs (4 out of 5), and 87.5% of secondary method (NIR) labs (7 out of 8) are considered in good standing (one laboratory conducted secondary method on both whole fruit and olive paste and was therefore counted
as two separate participants). Both groups demonstrated improved passing rates compared to the 2024/25 season. These are labs that fully participated and aligned on the ring test as repeatable and accurate results and completed the testing in its entirety.
as two separate participants). Both groups demonstrated improved passing rates compared to the 2024/25 season. These are labs that fully participated and aligned on the ring test as repeatable and accurate results and completed the testing in its entirety.
Labs in Good Standing
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Official Method
California Olive Ranch Modern Olives Laboratory UC Food Quality Laboratory Eurofins Food Chemistry Testing Des Moines, Inc. |
Secondary Method
California Olive Ranch Modern Olives Laboratory Corto Olive Company G&S Milling The Mill at Kings River, LLC Eurofins QTA, Inc. |
