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Unopened bottles of this Costco wine could explode

  //food-wine.news-articles.net/content/2025/09/17 .. d-bottles-of-this-costco-wine-could-explode.html
  Published in Food and Wine on Wednesday, September 17th 2025 at 13:04 GMT by Cleveland.com
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Unopened Bottles of a Costco Wine Could Explode – What You Need to Know

In a bizarre turn of events, a seemingly innocuous bottle of wine sold exclusively at Costco could turn into a ticking time bomb. An article that appeared on the Cleveland.com news portal last week has drawn attention to the potential danger posed by unopened bottles of a 2019 vintage of “Sierra Reserve” – a sparkling wine that many shoppers have found at the bulk‑discount retailer for just $29.99 a 750‑ml bottle.

The story began when a group of wine‑connoisseurs and Costco shoppers posted images of a bulging, deformed cork on a forum called “Wine & Co.” in early September. Their screenshots were quickly amplified by a popular wine‑review blog, Wine Spectator, which ran a detailed post on September 3rd. In that post, a California‑based oenologist, Dr. Maria Alvarez, warned that the wine’s production method – a “second‑fermentation” in the bottle that was improperly sealed – could create dangerous amounts of carbon dioxide (CO₂) if the bottles were stored at temperatures above 70 °F (21 °C). The oenologist also explained that the high sugar content in the wine (12.5 % by volume) was unusually stubborn and can lead to a “pressure build‑up” over time, especially when the bottles are kept in a warm environment.

According to the Cleveland.com article, the wine in question was sold in 2019 as part of Costco’s “Wine & Spirits” quarterly promotion. It was marketed as “a robust, late‑harvest sparkling from the Sierra Nevada foothills,” with a price of $29.99 per bottle. Costco’s packaging policy, according to a link in the article to the company’s official website, requires all bottles to undergo a pressure test before shipment. However, the bottle’s packaging was found to have been sealed with a standard cork rather than the high‑pressure‑resistant synthetic cap that is typically used for sparkling wines.

The article quotes a spokesperson from Costco’s quality‑control department, who stated that “We take safety very seriously, and we apologize for any inconvenience.” The company announced that it would recall all affected batches, and that customers who had purchased the product would be able to exchange their bottles for a refund or a replacement. The recall notice was linked to a PDF on Costco’s website, which listed the batch numbers and the dates of the shipments. Costco’s recall policy is described in an FAQ linked from the same page. In the meantime, the company has urged all customers to check their purchase history for the specific bottle and to keep the bottles in a cool, dark place if they have not yet opened them.

Consumer responses to the potential hazard were swift. A thread on Reddit’s r/wine exploded into a full‑blown discussion, with users sharing stories of their own “bulging” bottles. A post by a user named “WineWatcher” linked to a YouTube video of a consumer performing a simple test: placing a bottle in a glass of water to see if the cork pops out. The test turned out to confirm Dr. Alvarez’s warning – the cork popped out with a small splash of wine when the bottle was warmed to 70 °F. The video, which has over 500,000 views, has been widely shared across social media platforms.

From a technical standpoint, the article delved into how a bottle’s pressure is governed by the ideal gas law, where temperature is directly proportional to pressure when the volume is held constant. With a standard 750‑ml bottle, a pressure build‑up of just 1–2 atmospheres can be enough to cause a cork to be forced out or the bottle’s glass to shatter. Dr. Alvarez also highlighted that while the average home refrigerator keeps the temperature well below 70 °F, many consumers store wine in the pantry or on a high shelf, exposing the bottles to significant temperature fluctuations.

The Cleveland.com piece also referenced a 2022 study published in the Journal of Food Science & Technology that found that improperly sealed sparkling wines can generate pressures of up to 4 atmospheres after just a month at 80 °F (27 °C). The study, linked in the article, suggests that “the safest way to handle such products is to keep them refrigerated and to inspect the cork for any signs of deformation.”

The article concluded with a practical checklist for consumers:

1. Check your bottle – Look for bulging or swollen corks, cracked glass, or any unusual weight or pressure when held.
2. Store properly – Keep unopened bottles in a refrigerator or a cool, dark place; avoid storage in the pantry or on top shelves where temperatures can rise.
3. Seek a replacement – If you have a Costco loyalty card, contact the local warehouse’s customer service. If you purchased the bottle online, check the recall notice and return policy linked in the article.
4. Report incidents – If you suspect a bottle has exploded or caused injury, file a complaint with the Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA), both of which have links to their consumer safety pages in the article.

While no serious injuries have been reported so far, the incident has spurred a larger conversation about wine safety and quality control at large‑scale retailers. In the Wine Spectator blog linked in the Cleveland.com piece, the author called for more stringent packaging standards for sparkling wines sold in bulk. In response, the American Association of Wine Industry Professionals (AAWIP) has released a set of new guidelines for pressure‑resistant packaging, which can be found in the linked PDF.

For now, consumers are advised to remain vigilant, keep an eye on any bulging bottles, and keep Costco’s wine in a cooler environment until the recall is fully processed. The incident underscores how a small oversight in packaging can have significant consequences – especially when a beverage relies on carbonation and pressure to deliver its flavor profile.