Costco Kirkland Tequila Lawsuit 2026, Lab Tests Say It Is Not 100% Agave, Here Is What Shoppers Need to Know

Costco is facing two separate class action lawsuits over its Kirkland Signature tequila line — both accusing the retail giant of selling tequila falsely labeled as “100% Blue Weber Agave” that laboratory testing reveals actually contains significant levels of non-agave alcohol. The first lawsuit was filed November 14, 2025 in the US District Court for the Western District of Washington by Seattle-based consumer rights firm Hagens Berman, accusing Costco of knowingly selling adulterated tequila that contains significant presence of non-agave sugars.

 A second lawsuit was filed October 31, 2025 in the US District Court for the Southern District of Florida by plaintiff Ariel Glazer, also alleging the Kirkland tequila line is falsely labeled and contains ethanol from non-agave sources. Both cases are active and ongoing. No settlement has been reached. Costco has not publicly responded to either lawsuit.

Quick Facts

• Cases: Glazer v. Costco Wholesale Corp. (S.D. Fla.) | Hagens Berman class action (W.D. Wash.)
• Filed: October 31, 2025 and November 14, 2025
• Products named: Kirkland Blanco, Reposado, Añejo, Añejo Cristalino, Extra Añejo tequilas
• Price range: $18.69 to $48.99 per bottle
• What the lawsuits claim: Kirkland tequila is labeled “100% de Agave” but contains cane sugar and other non-agave alcohol
• Evidence: Nuclear Magnetic Resonance (NMR) and isotope scientific testing
• Current status: Active litigation — no settlement, no verdict
• Costco’s response: No public statement issued
• Can you claim money now? No — cases are too early for any claim filing

What Does “100% Agave” Actually Mean?

Before getting into the lawsuits, it helps to understand why this label matters so much — and why it is worth a lawsuit in the first place.

Authentic tequila is made exclusively from Blue Weber agave — a plant that takes seven to ten years to mature before it can be harvested. That long growing cycle, combined with the skilled labor required to harvest and process agave, makes genuine 100% agave tequila significantly more expensive to produce than alternatives.

The cheaper alternative is called mixto tequila — a blend where only 51% of the fermentable sugars must come from agave, with the remaining 49% coming from cheaper sources like cane sugar. Mixto must be labeled as such under both US and Mexican law. It cannot be labeled “100% agave.”

According to the lawsuits, NMR testing showed that Kirkland Signature Añejo Cristalino contained material amounts of ethanol not derived from agave plants — and did not even meet the necessary parameters for mixto tequila, meaning by Mexican law it cannot qualify as tequila at all.

Lab tests revealed that Kirkland Blanco tequila contains anywhere from 60% to 80% agave-derived ethanol, and Kirkland Reposado contained only 5% to 25% agave-derived ethanol — both products are labeled “100% de Agave.”

If those test results hold up in court, Costco shoppers who paid premium prices for what they believed was pure agave tequila were paying for something fundamentally different from what the label promised.

Two Lawsuits, Same Core Claim

Lawsuit One — Glazer v. Costco (Florida)

Plaintiff Ariel Glazer commissioned Nuclear Magnetic Resonance testing, which can identify the plant origin of methanol, and used those results as the foundation of the Florida complaint. The lawyers argue the test results implicate the entire Kirkland Signature tequila range because all varieties are supposedly made from the same base spirit.

Glazer is seeking a jury trial and an injunction to stop Costco from continuing to sell the mislabeled products. The proposed class covers all US consumers who purchased any falsely labeled Kirkland tequila during the applicable statute of limitations period.

Lawsuit Two — Hagens Berman (Washington)

The Hagens Berman lawsuit makes the most serious legal claim of the two — accusing Costco of violating the Racketeer Influenced and Corrupt Organizations Act, commonly known as RICO, a law typically used against organized criminal enterprises. The lawsuit also names Costco’s tequila supplier, Santa Lucia Corporate Distillery of Mexico, as a co-defendant, alleging both companies knowingly participated in the scheme.

The lawsuit states: “By falsely branding Kirkland Tequila Products as ‘100% de Agave,’ or ‘100% Blue Agave,’ Costco misled consumers, distorted the premium tequila market, and profited from a deception that violates the core principles of consumer protection law.”

A RICO claim is unusual in a consumer product case and signals that the attorneys believe they can prove Costco had knowledge of the adulteration and continued selling the product anyway — not just negligence, but intentional conduct.

The Science Behind the Claims — What Is NMR Testing?

Both lawsuits rely heavily on Nuclear Magnetic Resonance testing — a scientific method that can determine the biological origin of alcohol molecules in a liquid sample.

NMR testing has been approved by the Mexican government as a legitimate method for determining whether a tequila is genuinely 100% agave. The testing can identify whether methanol and ethanol in a spirit originated from agave plants or from cheaper sugar sources like cane.

This is not a fringe testing method. It is the same technology used in food safety and pharmaceutical research worldwide. When NMR results show that a bottle labeled “100% agave” contains significant amounts of cane-derived alcohol, that is a scientifically meaningful finding — which is why multiple law firms have now used it as the foundation for lawsuits not just against Costco but against other major tequila brands too.

Similar lawsuits have been filed against Don Julio, Casamigos, Cincoro, and Kendall Jenner’s 818 Tequila — all alleging the same issue: tequila labeled 100% agave that test results suggest contains non-agave alcohol. Diageo, maker of Don Julio and Casamigos, has filed a motion to dismiss its lawsuits, calling the testing methodology unvalidated and the allegations baseless.

The broader industry dispute over NMR testing methodology will likely play a significant role in how all of these cases proceed.

Who Regulates Tequila — And Has That Failed?

The organization responsible for certifying tequila purity is the Consejo Regulador Del Tequila — the CRT. However, the Hagens Berman lawsuit points out that the CRT is not a governmental entity. It is a private non-profit organization whose board of directors and committees are dominated by representatives of the very tequila producers it is supposed to regulate.

In other words: the industry is largely self-policing. And the lawsuits allege that self-policing has failed consumers.

In early 2025, Mexican agave farmers staged large-scale protests in the historic central square of Tequila, Jalisco, calling attention to widespread adulteration in the industry and demanding that regulators take action. Those protests drew international media coverage and directly inspired the legal cases that followed — including the Costco lawsuits.

Is Kirkland Tequila Still Being Sold?

As of February 2026, none of the Kirkland Signature tequilas are listed as available on the Costco website. Whether that reflects a voluntary removal pending the litigation outcome, a supply issue, or a permanent discontinuation has not been confirmed by Costco. The products may still be available in some physical warehouse locations.

Costco has not issued any public statement addressing either lawsuit, has not issued a recall, and has not filed a formal response in either court case yet.

Can You Join the Lawsuit or File a Claim Right Now?

Not yet. Both cases are in very early stages — no class certification has been granted, no settlement has been reached, and no claim website exists. This is active litigation that will take months to years to resolve.

If you purchased Kirkland Signature tequila and want to stay informed about the case, keep your receipts or Costco membership purchase records. In false advertising class actions, documented purchase history typically results in a higher individual payment if a settlement is eventually reached.

When a settlement is announced and a claim website goes live, your site will cover it. In the meantime, if you believe you have experienced specific harm from purchasing tequila you now believe was adulterated, consulting a consumer rights attorney is a worthwhile step.

Key Terms Explained

100% Agave Tequila: Tequila made entirely from Blue Weber agave — the most premium category under both Mexican and US labeling standards. Commands higher prices because of the long agave growing cycle.

Mixto Tequila: A blend where at least 51% of fermentable sugars come from agave and up to 49% from other sources. Must be labeled as mixto and cannot be called “100% agave.”

NMR Testing (Nuclear Magnetic Resonance): A scientific method that identifies the biological origin of molecules in a liquid — used here to determine whether alcohol in tequila came from agave plants or cheaper cane sugar sources.

RICO Act: The Racketeer Influenced and Corrupt Organizations Act — a federal law originally designed to combat organized crime, now also used in civil cases alleging coordinated fraudulent schemes.

Class Action: A lawsuit where a group of people with the same legal claim sue a defendant together. No action is needed to join at this stage — class members are identified and notified if a settlement is reached.

This is not the first time Costco has faced legal scrutiny over its Kirkland Signature products in 2026. Our coverage of the Costco Rotisserie Chicken false advertising lawsuit covers a separate active case accusing Costco of falsely labeling its famous $4.99 chickens as “No Preservatives” — and our breakdown of the Costco Salmonella lawsuit examines another federal class action filed in February 2026 over contamination at Costco’s Nebraska poultry plant. Together these three cases paint a picture of growing legal scrutiny over Costco’s Kirkland Signature private label — one of the most trusted brand names in American retail.

This article is for informational purposes only and does not constitute legal advice. This article will be updated as the cases develop. For the latest case status, monitor court dockets at Glazer v. Costco Wholesale Corp., Case No. 1:25-cv-25057 (S.D. Fla.) and the Hagens Berman class action in the Western District of Washington.

Sources: Glazer v. Costco Wholesale Corp., Case No. 1:25-cv-25057 (S.D. Fla., filed Oct. 31, 2025) | Hagens Berman class action (W.D. Wash., filed Nov. 14, 2025) | Mezcalistas, November 2025 | The Spirits Business, November 2025 | Chowhound, February 28, 2026 | KOIN News, November 2025

About the Author

Sarah Klein, JD, is a licensed attorney and legal content strategist with over 12 years of experience across civil, criminal, family, and regulatory law. At All About Lawyer, she covers a wide range of legal topics — from high-profile lawsuits and courtroom stories to state traffic laws and everyday legal questions — all with a focus on accuracy, clarity, and public understanding.
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