People Have An Issue With Starbucks' New Protein Lattes & We Can See Why

CORRECTION 10/7/25: A previous version of this article stated the protein cold foams add 19-26 grams of protein to Grande drinks. Starbucks' protein cold foams add 15 grams of protein to the iced beverages ordered in that size.

With the release of Starbucks' protein-packed cold foam and lattes, which arrived in late September 2025, came excitement from fans who were looking to get more nutritional value out of their favorite beverages. The first week of one item's rollout, however, left much to be desired, at least according to some of those who tried the offering. Customers have reported problems with the Hot Protein Latte on platforms like Reddit and TikTok, as the special protein milk that the chain uses for this drink rapidly curdles, creating a texture that isn't just visually and physically off-putting, but also incredibly difficult to drink.

@the_sugarmamma

Wow @Starbucks new protein latte #starbucks #protien

♬ original sound – Sugarmamma

While Starbucks' long list of recalls doesn't include the protein latte just yet, this issue has already made the item deeply unpopular among fans online. Furthermore, while the chain hasn't yet confirmed why this issue is happening, one factor seems to be that many baristas didn't receive the proper instructions regarding how to make the drink. Some folks on Reddit have noted that the Hot Protein Lattes are meant to be made with both Starbucks' protein milk and its 2% milk mixed together, and the clumpy, curdled texture is most likely the result of baristas accidentally using too much protein milk in the drink.

Starbucks shared the following statement on the matter: "We always want customers to enjoy their Starbucks experience. If a beverage doesn't meet expectations, we encourage customers to let their barista know so the drink can be remade. Our goal is to make it right every time."

Beyond this likely barista blunder, customers are concerned that such a small slip-up can have such damaging results. Well, the reason why Starbucks' protein-boosted milk is so delicate is because the protein within milk is what causes it to curdle in the first place. Denaturation of milk's protein — which can happen when milk is heated in coffee or tea, or when it comes into contact with acidic liquids — results in a total breakdown of the milk itself, causing it to curdle and solidify. Because of this, the more protein there is in milk, the easier it curdles, making the hot version of Starbucks' new item prone to solidifying when it's not mixed with 2% milk as intended.

Starbucks will hopefully reinforce the recipe for its Hot Protein Lattes in the near future, as its new protein-packed menu has otherwise been fairly successful for the company. While they aren't quite the healthiest drinks you can get from Starbucks, fans have been impressed by the assortment of protein cold foams the chain provides, all of which add 15 grams of protein to Grande iced drinks. Similarly, despite its struggles in hot coffee, Starbucks' protein-boosted milk has seen minimal complaints when used in iced lattes since its September 29 rollout.