No, you generally should not pour boiling water directly into a cold glass jar because the rapid temperature change causes thermal shock, making the glass expand unevenly and likely crack or shatter, potentially causing burns. To safely use a jar with hot liquids, gradually pre-heat the jar with warm water first, use heat-safe types like Mason jars (though still with caution), or use specialized borosilicate glass (like old Pyrex) designed for temperature changes.
Temperature Difference (Thermal Shock)
When you pour hot water into a glass, the inside of the glass expands faster than the outside. This drastic difference in expansion causes enormous stress on the glass structure, causing it to crack or break.
Glass containers are a safe and practical choice for storing hot liquids. Glass containers made of borosilicate glass are perfect for preserving the taste and aroma of your hot liquids and keeping them safe for consumption.
Fill the pot with cold or room-temperature water until the jars and lids are completely submerged. Placing the jars straight into boiling water can cause them to shatter due to thermal shock.
For Everyday Kitchen Use: Tempered Glass is Best: When using glass containers with hot liquids, choose tempered glass mugs or containers. Tempered glass is specially treated to withstand temperature changes better than regular glass. Avoid Sudden Shocks: Don't pour boiling water directly into a cold glass jar.
When canning or storing hot soups, sauces, or beverages in mason jars, it's important to allow the contents to cool properly before sealing the jar. Adding boiling hot liquids to a room temperature glass jar can create thermal shock, which can cause the glass to expand too quickly and possibly crack.
Glass is a poor conductor of heat and when subjected to rapid temperature changes above 30°C, the glass can experience stress which over time can cause cracking. Thin glass will generally break at a temperature of 150°-160°C.
At what temperature does a glass jar break? Regular glass jars (soda-lime) crack at 150–200°C (302–392°F) when exposed to sudden thermal shock (source). Heat resistant jars can handle: Tempered glass: up to 450°F (232°C)
Yes, it's safe to put hot soup in a Mason jar—under certain conditions. Mason jars can crack or break if not handled correctly.
If you have a special application that REQUIRES boiling water (or water that's much hotter than the glass's normal temperature) then you want something that is "lab rated", or "borosilicate glass" (like they used to make Pyrex out of, before they started using cheap glass).
If there are no obvious markers and you're unsure about the color, you can also perform a heat test by applying a small amount of heat to the jar with a lighter. If it cracks, it's clearly not heat-resistant. But if it doesn't, it may be soda-lime glass.
and the temperature difference between the inside and outside of the cup is large. Remember, do not pour boiling water directly into the glass pot, otherwise it will break!
Are Mason Jars Heat Proof? Mason jars are made from a specific glass material called soda-lime glass. While you can heat mason jars to 392F maximum, it requires a slow heating process. This process may include first heating the mason jars under warm and hot water before using them in a warmer environment.
Thin glass, for instance, tends to crack and potentially break at 150°C (302°F) or higher. Toughened glass, however, is made with a special heat treatment that makes it withstand higher temperatures, as well as other forms of stress.
Glass won't leak chemicals into your meals. While plastic containers can release BPA and phthalates - especially when heated or worn - glass stays completely inert. You've probably noticed how plastic containers hold onto that spaghetti sauce smell or turn orange after storing leftovers.
Borosilicate glass or Pyrex is usually used for glassware that may be directly heated, such as beakers or boiling flasks.
If you don't want to wait before putting something hot in the glass, at least warm the glass container up. Just fill it with water as hot as the tap will get it, then dump it out before putting hot food in it. A chicken breast is low risk, but as others have said, hot food in cold glass can crack it.
You can drink your pipping hot coffee or slowly savor your iced latte in a Mason jar and never worry about what else is being added to your tasty beverage. Also, you can drink your hot or cold coffee so many different ways when you use a Mason jar.
Yes, you can safely boil water in borosilicate glass because it can withstand extreme temperature changes without cracking, making it ideal for pouring boiling water directly into a borosilicate glass container or bottle.
Most modern colored mason jars are made from the same soda-lime or tempered glass as clear jars, which is generally microwave safe without the lid. They're fine for short, low-heat tasks, like reheating soup or melting butter.
Dr. Shelke recommends glass containers — especially durable tempered glass — as they won't absorb odors or stains and are safe for reheating in the oven and microwave, though they're also relatively heavy and breakable.
Generally speaking, most common types of glass—like soda-lime glass used in windows and drinkware—can handle temperatures up to around 150°C (302°F) without breaking under normal circumstances. However, this threshold can vary significantly depending on how the glass was manufactured.
Thermal stress is caused when part of the glass becomes locally hotter, or colder, than the surrounding glass. This temperature mismatch causes stress from the localised expansion/contraction of the heated/cooled regions when constrained by the rest of the glass. If this stress becomes too great, the glass will crack.
To identify if the glass cup you are considering is made from high borosilicate heat-resistant glass, look for indications on the packaging or product description that mention its resistance to temperature variations. The material composition should specifically state "high borosilicate heat-resistant glass."