Is it bad to boil glass?
Glass or Wood Pieces
When it comes to glass or wood pipes, it's best to steer clear of boiling. Many people safely boil their glass or wood pipes, but you run the risk of weakening the glass or warping the wood if you do.
If a glass container is placed on a very hot source of heat (e.g., 500°C), it can gradually lose its shape and change from a permanent solid form to a plastic state. In general, glass jars should not be heated in a microwave or oven. Glass jars made of ordinary glass may crack or explode in a microwave.
You never want to add glass jars to a pot of boiling water because you can crack or shatter the jars. When the water has reached a full rolling boil, keep the jars in the canner for an additional 10 minutes.
When your glass jars order arrives, always clean and sterilize them using a hot water bath. The jars may “look” clean, and it may even come in a plastic shrink-wrap, but sterilize them with boiling water anyway to ensure cleanliness.
Place a pan of water over high heat until the water is on a rolling boil. Leave the glass jars to boil for 10 minutes, no more, no less.
The reason is that as the glass heats, its density changes; it expands. Pouring boiling water into a glass is highly likely to shatter it, because the hot water contacts part of the glass first, whereas other parts of the glass (such as the outside of the cup) remain cooler.
Mixing bowls of glass or stainless steel are heat-resistant and work best for double boilers.
The American Automobile Association (AAA) and the Automobile Association (AA) both recommend against using hot water on a windshield, which can crack or shatter glass due to the sudden change in temperature ( here , here ).
The thermal shock differential is the range of change that glass can generally withstand before experiencing shock and damage. For canning jars, this range is generally 90 degrees Fahrenheit.
When boiling water is poured into a thick tumbler its inner surface expands. However, due to low thermal conductivity of glass, the expansion of outer surface of the tumbler is quite small. Due to uneven expansion of the outer and inner surfaces, the tumbler breaks.
Is it safe to boil jar water?
Such chemicals might be harmful, can be removed only through the process of proper distillation and filtration. So yes, boiling water and consuming it is safe, but it might not be the safest method!
To pre-sterilize jars, place the cleaned jars right-side-up on a rack in a canner and fill the jars and canner with water to 1-inch above the tops of the jars. Bring the water to a boil and then boil for 10 minutes at altitudes less than 1,000 feet elevation.

Thanks to this, borosilicate glass has the ability to go straight from a freezer to an oven rack without cracking. For you, this means you can pour boiling hot water into borosilicate glass if you wanted to say, steep tea or coffee, without worrying about shattering or cracking the glass.
Glass objects are particularly vulnerable to failure from thermal shock, due to their low strength and low thermal conductivity. If the glass is then suddenly exposed to extreme heat, the shock will cause the glass to break.
A: Yes, you can pour boiling water into the mugs. Sometimes they break, sometimes they don't. To protect against exploding and cracking, place a stainless steel spoon inside the cup before pouring boiling liquids. The spoon absorbs the impact of the heat and protects the glass.
However, Pyrex bowls are not designed for stove top use so proceed at your own risk. Despite the name, when using a double boiler the heat should not actually bring the water to a boil. The low heat levels should be safe for your Pyrex especially when you consider they are safe to use inside the oven.
When hot water is run over the jar, both the glass and the I id expand, but at different rates. Since all dimensions expand, the inner diameter of the lid expands more than the top of the jar, and the lid will be easier to remove.
The special glass material we use to make our teapots can handle sudden temperature change. In other words, when you pour boiling water directly in glass teapot (even if you take glass teapot directly out of refrigerator), it wont break.
Liquids expand as they freeze, so when there isn't enough room the pressure builds up and causes the glass to break. Approximately one to two inches of empty space at the top of the jar is ideal, depending on what you're freezing.
Thermal shock is characterized by a crack running around the base of the lower part of the jar, sometimes extending up the side. To prevent thermal breakage: Avoid sudden temperature changes, such as putting hot food in a cold jar, putting a cold jar in hot water, or placing a hot jar on a cool or wet surface.
Are blue mason jars food safe?
COLORED JARS
Blue, green and purple jars have been made for home food preservation. However, there are other colored jars, such as yellow, available for craft projects, but are not recommended for food preservation.
Mason jars are made with annealed glass and not tempered glass as some people may think. Tempered glass - often used for cookware - undergoes a process of extreme heating and rapid cooling in order to make it stronger and safe for oven temperatures. When it shatters, the pieces of glass tend to be in pebbles.
When a window pane of ordinary float glass is first heated, it tends to crack when the glass reaches a temperature of about 150 - 200ºC. The first crack initiates from one of the edges.
Set the kiln to warm at 500 degrees per hour. This is the safest speed to heat glass without risking thermal shock. (Reference 1) When the kiln gets up to 1100 degrees, stop the temperature increase for 10 minutes, then continue heating the bottle at a slower rate of 250 degrees per hour.
Can I pour boiling water into a Mason jar? Yes, you can pour boiling water into your Mason jars, and you can also insert them into a pan full of boiling water for sterilization. However, make sure your Mason jars are at least room temperature before placing them into the water.
Although, some bacterial spores not typically associated with water borne disease are capable of surviving boiling conditions (e.g. clostridium and bacillus spores), research shows that water borne pathogens are inactivated or killed at temperatures below boiling (212°F or 100°C).
Mineral, structured, and pure spring water are some of the healthiest water you can drink because they're clean and contain all the essential minerals your body needs. Filtered water removes contaminants but might also remove essential minerals.
These recommendations have been followed by the New South Wales health authorities in responding to the contamination incidents. CDC recommends making water microbiologically safe to drink by bringing it to a rolling boil for one (1) minute.
As discussed above, it is thermal shock resistant, meaning you can pour boiling water into a borosilicate glass jug and it won't crack. The borosilicate glass is harder than regular glass as it can be moulded into more complex shapes.
Glass objects are particularly vulnerable to failure from thermal shock, due to their low strength and low thermal conductivity. If the glass is then suddenly exposed to extreme heat, the shock will cause the glass to break.
Can I put boiling water in a glass teapot?
The special glass material we use to make our teapots can handle sudden temperature change. In other words, when you pour boiling water directly in glass teapot (even if you take glass teapot directly out of refrigerator), it wont break. This is another special quality of glass teapot.
Borosilicate glass is a type of glass that contains boron trioxide which allows for a very low coefficient of thermal expansion. This means it will not crack under extreme temperature changes like regular glass.
Heat-resistant vessels are a must
Instead, you can simply use another vessel that will sit on top of any old pot you already own. MasterClass recommends using either a glass or stainless steel bowl as the vessel when constructing your own double boiler.