Did Costco Alter Kirkland Butter's Water Content? Reddit Says Yes

For avid bakers, the pressure to perform is never higher than it is around the holidays when the entire family expects your famously perfect pie. Because baking is an art form that allows little room for error, many home cooks rely on specific products that, through personal experience, have proven to work well with their tried and true recipes. So, when several holiday recipes went awry after Costco's Kirkland Signature Salted Butter was added to the mix, it prompted many loyal customers on Reddit to question whether the butter had undergone a recent change.

"My mom and I have been Costco 'blue box' salted butter loyalists for some time," one shopper wrote on a Costco subreddit. Despite hearing that a fellow baker on TikTok had a disappointing experience using the butter in a recipe that had successfully incorporated it for years, the Reddit user admits they didn't think much of the TikToker's accusations until the Kirkland brand butter derailed their own Thanksgiving pie plans.

After making two batches of "crumbly" pie dough that was impossible to roll out, the Reddit user says they went to the store and purchased a different brand of butter to see if it solved their problem. "Went to store got different butter ... and what do you know ... [the] same recipe, worked again," the confused Reddit user adds. "Something changed with their butter. Did anyone else have issues over the holidays with the butter?"

Several Costco shoppers hopped on the Reddit thread to express that they had a similar issue with their pie crusts after using Kirkland Signature Salted Butter this year. "Wait, are you kidding me? My Thanksgiving pie crust totally gave me 'crumbly' issues, and I'm usually a pie pro! I stock up on the blue box Costco butter and used it...," one Reddit user mused. Another noted that, although his wife used Costco's unsalted butter, she faced similar issues.

After a slew of baffled bakers expressed their outrage, a commenter with some baking know-how finally offered a possible explanation. "It's a change in the water content," the user explained. No matter where you get your butter from, it will contain some combination of water, butterfat, and milk solids. Butter with a higher water content inherently contains less fat, which can have a profound effect on the outcome of your baked goods, often leading to a tougher, "crumblier" dough.

While Costco has not confirmed that there has been a recipe change, Eat This Not That suggests the retailer may be adding more water to their butter recipe as a way to cut production costs. The helpful Reddit user says to use "Kerrygold only for baking from now on." While American butter typically contains 80% milkfat, European versions, like the Irish Kerrygold butter, contain somewhere between 82% and 90%.