The lawsuit, initiated by Ariel Glazer in Miami’s federal court on October 31, alleges that Costco’s Kirkland tequilas contain alcohol that is not derived from blue agave plants. This is significant because Mexican regulations stipulate that tequila must be made solely from blue agave to be considered authentic.

Five varieties of Kirkland tequila are at the center of this legal action: Blanco, Reposado, Añejo, Añejo Cristalino, and Extra Añejo. Each bottle prominently displays labels stating “100% DE AGAVE” and “100% AGAVE AZUL.” These tequilas are marketed both in Costco stores across the country and online, with prices ranging from $18.69 to $48.99 per bottle.

The complaint highlights specific findings from the testing of Kirkland Signature Añejo Cristalino. The results indicated the presence of alcohol not sourced from agave plants; instead, it was more akin to alcohol derived from sugarcane or corn. The lawsuit argues that these findings do not meet the standards for 100% agave tequila and even fall short of the criteria for “mixto” tequilas, which Mexican law permits to include up to 49% non-agave sugars.

According to the complaint, testing of Kirkland Signature Añejo Cristalino showed it was contained alcohol not derived from agave plants — results found it to be more consistent with sugarcane or corn alcohol rather than agave. The lawsuit alleges the results fall outside acceptable ranges not just for 100% agave tequila, but even for “mixto” tequilas, which Mexican law allows to contain up to 49% non-agave sugars.

Because all Kirkland tequilas start from the same base distillation of Blanco tequila, the lawsuit argues the contamination affects the entire product line.

True tequila must be made exclusively from Blue Weber agave plants grown in specific regions of Mexico, primarily Jalisco state. The plants take five to 10 years to mature before harvest, making authentic agave spirits significantly more expensive than alternatives.

The lawsuit notes that even adding small amounts of cheaper alcohols like sugarcane-derived ethanol would violate both Mexican standards and U.S. labeling requirements under the Federal Alcohol Administration Act.

The plaintiff, who purchased a bottle of Kirkland Reposado from a Costco in Royal Palm Beach, Florida, on Oct. 28, is seeking to represent a nationwide class of consumers who bought the products.

The lawsuit includes claims for negligence, negligent misrepresentation, unjust enrichment and violations of consumer protection laws.

“If Plaintiff and others similarly situated had known the truth of the ingredients in the Products, they would not have purchased the Products or would have paid less for them,” the complaint states.

Costco has not yet responded to the allegations in court.