Material purity: high-quality glass milk bottles are made of pure material, free of impurities, bubbles and obvious flaws. You can observe the bottle against the light, if the interior is clear and transparent, no turbidity and foreign matter, usually the material is better.
Bottle wall thickness: uniform and moderate thickness of the bottle wall quality is better. If it is too thin, it may break easily. If it is too thick, it increases the weight and cost. Gently touch the wall of the bottle with your hand to feel whether its thickness is consistent.
Sealing: Check to see if the mouth and cap of the bottle fit tightly without any looseness or gaps. It can be filled with water and inverted or tilted to observe if there is any leakage.
Heat resistance: If the milk needs to be heated, then the heat resistance of the bottle is important. A good quality glass milk bottle can withstand certain temperature changes without breaking.
Appearance flatness: the bottle should be flat and smooth, without obvious bumps and deformations.
Strength and toughness: gently knock the bottle, listen to the sound is crisp. Crisp sound is generally better strength; you can also apply moderate pressure to feel the bottle's pressure resistance.
Brand and production standards: Choose well-known brands and products that comply with the relevant production standards, the quality is usually more guaranteed.
