Starbucks Iced Guava White Tea Lemonade

Is this Starbucks drink ok?

https://www.starbucks.com/menu/product/2123078/iced?parent=%2Fdrinks%2Ficed-teas%2Ficed-white-teas

Ingredients

Ice, An Infusion Of [Water, A Blend Of White Teas], Guava Flavored Juice Blend [Water, White Grape Juice Concentrate, Natural Flavors, Guava Juice Concentrate, Colored With Fruit And Vegetable Juice (Pumpkin, Sweet Potato, Apple, Radish, Cherry), Citric Acid], Lemonade[Water, Lemon Juice, Sugar, Lemon Oil], Liquid Cane Sugar [Water, Turbinado Cane Sugar, Cane Sugar, Natural Flavor, Potassium Sorbate, Citric Acid]

Not Kosher

Is the “White Grape Juice Concentrate” the issue here? Seems like a very small percentage of the overall drink.

Unless you can ascertain what that percentage is, we can’t make assumptions.

I’m confused. There have been many posts on this site for many years explaining that all grape juice in the US is flash boiled/mevushal and thus kosher. Can you please explain what the issue is?

There is an assumption that this is the case, and we have verified this with some companies. However as a general rule we can’t be sure that there’s never human contact with the grape juice prior to the pasteurization process. When unsure, we must rely on Bittul.