Can I put the pure copper beer cup in the freezer to use it colder?

While there is a habit of freezing cups in advance in the freezer to enjoy beer colder, this method should be avoided for pure copper cups. Among metals, copper has a very high thermal conductivity and is sensitive to temperature changes. Putting the cup in a sub-zero freezer environment can cause damage such as warping or cracking of the metal shape due to the sudden temperature difference^[1].

Even without pre-freezing, a pure copper cup is more than enough to enjoy coldness. This is because the moment you pour a cold drink, the chill spreads quickly across the entire surface and is instantly transmitted to your fingertips and lips. Meanwhile, copper naturally oxidizes starting from the manufacturing process and may retain faint scratches, but this is an inherent property of the material rather than a defect^[2]. Passing the drink's natural chill directly through the cup without freezing it is the tip for using copper tableware intact for a long time.