1. Prioritize High-Borosilicate Glass: This material boasts a heat resistance of up to 450°C; it is highly resistant to thermal shock (sudden temperature changes) and is unlikely to shatter. Furthermore, it contains no organic chemical substances, making it one of the healthiest choices for drinking vessels.
2. Avoid Four Types of Risky Cups:
* Colored Glass Cups: The pigments used may contain heavy metals; when exposed to hot water, these substances can easily leach out. Therefore, using them to hold hot beverages is not recommended.
* Soda-Lime Glass Cups: These have poor heat resistance and are prone to shattering when subjected to alternating hot and cold temperatures. They typically feature a visible seam line on the body and are suitable only for holding room-temperature water.
* Lead-Containing Glass Cups: Metals such as lead and zinc are added to enhance clarity and brilliance. However, contact with hot water or beverages can easily cause harmful substances to leach out. Particular caution is advised when selecting "crystal glass" products.
* "Fake" Glass Cups: These are actually made of tempered plastic. They lack food-grade safety certification, and an unusually low price point should serve as a red flag; long-term use poses a risk to health.
3. Identification Tips: High-quality glass cups are transparent, free of impurities and air bubbles, produce a crisp and pleasant ringing sound when tapped, and emit no pungent or unpleasant odors.