The bottle is likely to break if you add ice at force, change temperatures quickly, knock your bottle over, or use metal spoons or instruments inside the glass bottle.
Avoid large temperature changes
Do NOT – pour cold water into the glass bottle when it’s hot or vice versa. Going from hot to cold too quickly can cause the glass to break. Be sure that your glass bottle has cooled to room temperature after washing before you put in cold water and especially ice inside.
Leak Proof Seal
The seal inside the lids should be pushed down with the “groovy” side inside the lid and the smooth side facing you. Make sure the seal, which makes the lids leak proof, is completely pushed down inside the lid. If the seal isn’t completely in place, it’ll cause a very strong vacuum. This will cause the lid to close too tight, making it hard to open, and might cause the bottle to break.