Protein shakes can get lumpy or clumpy if you don’t mix them properly. That’s why a shaker bottle is better at mixing whey into milk than just stirring with a spoon. A blender works even better, if you want to clean the blender when you’re done. But there’s a better option: a handheld frother.
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To be clear, this is for drinks where you mix powder into liquid. (If you want ice and fruit in your protein shake (a smoothie instead of a plain drink), you still need a blender. But you already knew that.) As far as I can tell, it works with any powder and any liquid. I tested the frother and found it to give excellent results with:
Collagen powder and coffee (or tea)
Whey powder and water