If you’re already frustrated by the long lines at your local Starbucks, just wait: it may soon take a little longer for your barista to whip up your next grande mocha frappuccino.

Amid customer complaints that the Seattle-based coffee chain has turned coffee-making into something more akin to a factory assembly line, The Wall Street Journal reports that Starbucks is telling its busy baristas to slow down, and the change of pace behind the counter may result in longer lines.

Starbucks has instructed the coffee chain’s baristas (from the Italian for “bartender”) to stop making multiple drinks at the same time (no more than two at a time, according to the report). Baristas also are supposed to steam milk for each drink rather than steaming an entire pitcher to be used for several beverages. Other instructions include rinsing pitchers after each use, staying at the espresso bar instead of moving around and using only one espresso machine instead of two, according to company documents obtained by the newspaper.

Starbucks is making the changes, which it expects to roll out nationwide and across Canada by next month, as part of a company effort to make its stores more efficient, the Journal reports. It says Starbucks believes the new procedures will eventually hasten the way its beverages are made and lead to fresher, hotter drinks and reduce the “possibility for errors.”

Starbucks spokeswoman Trina Smith told the paper that it will take time for baristas to become comfortable with the new drink-making method, but some baristas interviewed by the Journal are worried that the changes will create longer lines.

“While I’m blending a frappuccino, it doesn’t make sense to stand there and wait for the blender to finish running, because I could be making an iced tea at the same time,” Tyler Swain, a barista in Omaha, Neb., told the Journal. He also said he is worried that he will not be able to keep up with volume if he can only complete one drink at a time.

Erik Forman, a Starbucks barista in Bloomington, Minn., confirmed these fears. He told the paper his store adopted the new drink-making guidelines last week and said the changes have “doubled the amount of time it takes to make drinks in some cases,” resulting in longer lines.