Starbucks has been testing the Milk Chocolate Mocha. This is not the same milk chocolate sauce that is used in the S'mores Frappuccino. The stores that have the Milk Chocolate Mocha test have 3 mocha sauces: The traditional dark chocolate mocha that all Starbucks have; the seasonal milk chocolate sauce used in the S'mores Frappuccino, and the milk chocolate sauce used just for the Milk Chocolate Mocha. (Actually, you could say that they have 4 mocha sauces if you count the skinny mocha sauce too.) The stores testing the Milk Chocolate Mocha are located in greater Sacramento cities, such as Folsom and Rocklin, and isolated stores in North Eastern Ohio.
The Milk Chocolate Mocha launched March 22nd this year. My understanding is that the test was supposed to end at the end of April, but a number of stores haven't used all their special test milk chocolate sauce and so are still making the test mocha, if it's ordered. I had the chance to try this drink in greater Sacramento on May 21, 2016. One thing to notice is that the Milk Chocolate Mocha is noticeably lighter in color than a traditional mocha:
The Milk Chocolate Mocha is the one with "MCM" written on the side of the cup. It's a much more subtle and soft mocha flavor than the dark chocolate mocha. When you drink the two side by side, the traditional mocha is almost overwhelming in comparison. The Milk Chocolate Mocha is good, but I don't imagine it will be popular. It just seems as though Starbucks customers tend like lots of flavor, not subtle mocha notes. The test Milk Chocolate Mocha is milk, milk chocolate sauce, and espresso.
You can see that the two milk chocolate sauces (one for the S'mores Frappuccino and the other for the test Milk Chocolate Mocha) are different from each other:
Actually, if you make mocha drinks with all 3 variations of mocha sauce, you can see the difference again in the colors in them:
The lightest of the three above mochas is the mocha made with the S'mores milk chocolate sauce. The S'mores version of the milk chocolate mocha is rounder, soft, and almost a bit buttery!
There is currently no signage for this drink. As you can see, I tried the test drink on the tail end of the test. But I hope you get a chance to try the test Milk Chocolate Mocha! You'll have to specifically ask for it. And keep in mind, the test drink is only in a limited number of stores.
The upshot of it all is that I don't see this being wildly popular.
Starbucks has tested other variations on the mocha. It wasn't that long ago that Starbucks tested a mocha made with actual truffles! Delicious!