Is it a tempered glass mug? I'm intending to use it to heat very cold milk with steam, in a espresso coffee machine. Will it crack?
1942678
Not sure about the tempered glass but I pour boiling water over my teabag every morning & it's been fine. The only problem I've had is being very careful when washing them; they crack & chip easily but I'm on my second set of 4. I really like them; they hold about 16 0z of fluid each.
2267966
Can be used as coffee mug. Not for science experiment heat. Came with no packaging nor sure who made it
894893
I've broken a few over the past 40 or so years and don't notice any difference in quality or tempering. I do put them in microwave full of water and heat to boiling for tea. I don't believe they are tempered like clear glass arcoroc mugs which I have seen bounce off a concrete floor without damage.
1250950
Mine feels and looks like glass or a VERY high quality plastic. I've never felt it get cold or hot on the outside even when my espresso is steaming but the inner walls do kinda fog. If its REALLY hot then the outside might feel slightly warm but its barely noticeable. Maybe you have a defective one? Im not sure. :(
240838
SO: 2 answers, we just use cold. But in general, with glass (or ceramic) breaking comes from thermal shock. If you warm the mugs first, with hot water (rather than pouring the boiling water in them when they are cold) you will be much less likely to have problems.
49005
The mug is made of thick Borosilicate Glass. It also goes by the name of Pyrex. It is renown for its ability to withstand thermalshock. It can be heated by a bunsen burner.I am pretty sure it is microwavable :)
345016
I would not recommend putting this mug in the microwave. The ceramic handle for this mug appears to be hollow and would most likely crack. However it is a beautiful mug !! I love mine.
1619279
No, the glass is not tempered; I checked prior to making the purchase. I shopped around and asked questions about glass table tops before buying. I was told by the owner of a professional glass making company that tempered glass is not normally used for table tops. I purchased the 45-inch as a replacement for the one I accidently broke. It's been on my table in a very busy kitchen since November 2009. I am very pleased with it and have had no problems. I would buy it again without question.
2229669
The inside is completly steel. But the grid of the press that brews the coffee has some plastic. It is a great mug!
175239
i have not had a problem with this item. I've dropped a few times but no scratches or paint coming off. I believe the exterior is metal. all I know is this I'd the BEST hot/cold hand carried mug I have ever purchased. I wonder where it's been with the money I have wasted on mugs that claim to do what this one does. I have purchased a second one already and will purchase more in the future. All the other mugs I've had are in the trash.
1275802
After using ours for a few months, I am beginning to notice a crack on the outside of the cup. It may be from the dishwashing. I do continue to use it for hot coffee. They are supposed to be guaranteed for life of normal wear.
1594888
We heat our water with an electric kettle and immediately pour it into the teapot. The glass is fine and the outside of it heats up about as much as you'd expect. No cracks so far after a few weeks of daily use.
289602
The lid is a press - not insulated, but I doubt it would be worthwhile for it to be insulated. This is not a thermos, but a French press that does a pretty good job keeping coffee hot for longer than a glass carafe would. Use a tea cozy or put the coffee in a real thermos if you want long term heat retention. And....it won't break - a real plus.
547288
Mine cracked, but it was my own fault. I poored cold water into it after it was heated up too long :-(
983141
Don't know... haven't tried it... I suspect it isn't tempered glass. I want them for keeping things cold, though the literature says they are just as good for hot beverages.
1884816
I wouldn't risk it. The glass is such poor quality that one of mine even arrived from the factory with a hairline crack, in a place that was not likely cracked due to shipping damage. (After multiple emails, my latest replacement still hasn't arrived.). This type of glass is technically supposed to be more resilient when heated and cooled, but unfortunately that isn't true of this particular product.
634674
Sorry but I cannot tell if the glass is tempered or not. I'm just cautious and lay my hair styling tools on a heat resistant mat. So far nothing has cracked or shattered.