The California Wine Market Index™ (CWMI) is built using publicly available California Department of Food and Agriculture (CDFA) Grape Crush Reports. The methodology is designed to produce a transparent, repeatable, and objective benchmark that measures long-term movements in California wine-grape values.
Data Sources
The CWMI uses annual production, purchased tonnage, and statewide weighted average grower prices reported in the official California Grape Crush Report. These data are independently published each year by the California Department of Food and Agriculture and represent the most comprehensive publicly available record of California wine-grape market activity.
Index Construction
The California Wine Market Index™ combines annual statewide weighted average grower prices with purchased wine-grape tonnage to create a standardized market benchmark. Historical values are normalized to a common base year, allowing meaningful comparisons across time while reducing the influence of short-term market volatility.
Weighting Methodology
Each year’s index value reflects both price and market participation. Purchased tonnage serves as the weighting factor, ensuring that varieties and regions with greater economic importance have proportional influence on the index. This approach more accurately represents statewide market conditions than simple price averages alone.
Data Quality and Verification
All source data are obtained directly from official California Department of Food and Agriculture (CDFA) Grape Crush Reports. Before each annual update, production volumes, purchased tonnage, and weighted average prices are reviewed for completeness and consistency. Any revisions published by CDFA are incorporated into subsequent index calculations.
Annual Updates
The California Wine Market Index™ is updated annually following publication of the official California Grape Crush Report. Historical values remain available to allow long-term trend analysis while maintaining a consistent methodology from year to year.
Limitations
The California Wine Market Index™ measures statewide wine-grape market performance and should not be interpreted as the value of any individual vineyard, winery, grape variety, or geographic region. Local market conditions, contract structures, and quality premiums may differ from statewide averages.
Data & Methodological References
- California Department of Food and Agriculture (CDFA) Annual Grape Crush Reports
- California Wine Market Index™ historical series, 2000-2025
- CWMI Annual Market Report
- CWMI methodology and supporting research documentation
California Wine Index 