Surly Brewing Co. has announced it is recalling bottles of its 2018 BAOW!—or Barrel-Aged Oat Wine—from specific bottling days in June.

According to a post on the Minneapolis, Minn.-based brewery’s website, routine microbiological analysis found wild yeast in specific batches of the 9.6 percent ABV ale which create a “funky or tart off-flavor that was not intended in the style.”

“Our quality assurance team conducts sensory and microbiological testing on every batch of beer we make throughout its entire “life cycle”…(that) starts during brewing and continues well after a beer is on shelves,” reads the post. “(The affected beer) is not harmful to drink; it will simply have a different flavor profile. We have not received any consumer complaints of off-flavors but know they will develop the longer the beer is stored.”

Due to the issues, Surly is offering reimbursements for any impacted bottles that were packaged on either June 11 or June 12. No wild yeast was found on bottles packaged on June 18.

Customers who have purchased compromised bottles and would like to receive a refund should fill out this form on Surly’s website or send an email to [email protected] with a full name, address, where the bottle(s) were purchased and a photograph of the bottle.