What temperature will crack glass carboy?

[doublehaul]

On my second batch. My first batch I added 2 or 3 gallons cold water first, and then dumped the wort in, and the cold water would absorb the shock of the hot wort. This recipe, the hot wort is 4.5 gallons so I can't add too much cold water first. What is a safe temp to add the wort and not worry about cracking the glass carboy?

 

[poislb]

On my second batch. My first batch I added 2 or 3 gallons cold water first, and then dumped the wort in, and the cold water would absorb the shock of the hot wort. This recipe, the hot wort is 4.5 gallons so I can't add too much cold water first. What is a safe temp to add the wort and not worry about cracking the glass carboy?

I dont think ya have nothing to worry about. Now if the carboy is at 32 degrees and ya add 100 degree wort, now that would be a problem...

 

[brewd00d]

You would only need to worry about cracking if the carboy was heated up to a high temp then put into ice cold water, then maybe it would crack. But adding liquids into it, you dont need to worry about it cracking.

 

[paulster2626]

I added 4.5 gallons of red hot wort to a 6 gallon carboy with 1 gallon of room temp water already in it. Don't ask why - it was one of those messed up brew days and a learning experience.

Point is, the carboy didn't crack - so you have nothing to worry about.

 

[doublehaul]

Thanks. It seems more convenient to cool to below 75F in the stockpot for taking temperature readings though - otherwise wouldn't you need to take a sample everytime to take the temp? Although I don't really like it sitting there all exposed while cooling - I have a towel over the stockpot because I don't have a lid.

 

[doublehaul]

I guess I have some time to kill anyways...

 

[subliminalurge]

If you have a lid for your stock pot, then there's really no good reason to transfer into a carboy while the wort is still hot. The lid will prevent contamination and the thin metal walls will conduct heat faster than thick glass, allowing faster cooling.

If you have room in your pot, then having a gallon or two of pre-boiled, pre-chilled top off water to pour into it can massively cut down on your cooling time.

 

[Surly]

Although slightly OT, it does relate to cracking carboys:

Be very careful when setting a carboy down on concrete. Even a slight bump can crack them. Best to put them down on a carpet square or plywood.

 

[JustusLiebig]

I cracked one carboy full of sub 160 F water when I stuck it in my bathtub and ran some room temperature water around it. I was shocked. It was a total pain in the ass to pull it apart so that it didn't split in half in my hands. Then, I had to rush to the brew shop and buy another one and reboil more water. Err on the cautious side.

 

[rburrelli]

I cracked one carboy full of sub 160 F water when I stuck it in my bathtub and ran some room temperature water around it. I was shocked. It was a total pain in the ass to pull it apart so that it didn't split in half in my hands. Then, I had to rush to the brew shop and buy another one and reboil more water. Err on the cautious side.

And you bought ANOTHER carboy after that?

 

[grampamark]

Doing something once, and not experiencing a bad outcome, is one data point. Doing something once, and experiencing a bad outcome, is one data point.

The trick is-determining where, on the bell curve, your next attempt will land.

 

[RM-MN]

I poured boiling wort into my bucket fermenter. No problem, nothing broke.

 

[DVCNick]

Even if some people have done it successfully, I would not put hot wort into a room temperature carboy.

I don't believe they are constructed with the additives or whatever that an Erlenmeyer flask is (which allows those to take the thermal shock without cracking) as their price certainly doesn't reflect it.

My plastic fermenters all say "don't exceed 140F" so I wouldn't do that in a plastic fermenter either.

Basically, I would always cool to at least a reasonable level prior to transfer to fermenter.

You could buy some sheet metal at Home Depot and make a cover if you can't find a "proper" lid for the kettle.

 

[Cavpilot2000]

Yeah, there isn't so much a temperature that will cause it to break - the issue you experienced is two significantly different temperatures in contact with the glass at the same time. If you do that again, you will get the same result. Put any hot glass in cold water and watch out.

Plus glass can, like steel or other metals, develop invisible stress points and microfractures over time. You'll never know they're there until it fails, usually spectacularly.

To avoid problems, only ever put cool liquids in your carboy.