WeeSprout glass cups are made of very thick glass. However, it’s possible for all glass to break with extreme temperature changes. Because of this, we recommend using care when transitioning your jars between extreme temperatures. Check out some tips below:
Let baby food cool before storing,
Leave room for expansion when filling your jars,
Avoid going immediately from the freezer to very hot water,
Do not microwave cool jars except on a low setting.