Does the cold water have just a small sting of a metallic aftertaste? We know you can feel it in your stainless steel coffee mug as well. At Asobu® we strive to Elevate Your Everyday, by making these small problems disappear. That is why we created our PURAMIC line of bottles and mugs. Once you use these ceramic-lined insulated bottles you won't be able to use a regular stainless steel bottle again.