Erlenmeyer flask broke while heating: WTF?

What brand was it? If it wasn't Pyrex brand, then that may be your answer.

 

You're lucky you didn't take a shard of glass to the face, honestly. I would assume that you'd be better off trying to heat with an open flame of some sort, but as said above ^^^ not all glass is tempered the same and the strengths vary.

As for me, I'll heat wort and cool wort in a pot. I'll use a sink full of cold water and ice cubes to cool the wort quickly. I'll use StarSan on the flask, the foil on top, and the stir bar. I'll add the wort when it's fairly cool to the touch and center the magnet. I place a paper towel between the stirplate and the flask anymore. It keeps noise down and you never know when yeast is going to get unruly and try to get out.

 

To elaborate a little....even if your flask was borosilicate, it may not be high quality. Bomex is typically a cheap alternative to Pyrex. Although they are generally the same type of glass, the quality is much different. I've found, that in lab, Pyrex is much more reliable. The cheaper glassware is more prone to tiny scratches that can cause it to shatter when subjected to a sudden temperature change. Don't even get me started with the cookware they call pyrex (it's actually just soda lime glass). Check out science direct out of Colorado. They sell pyrex brand, and it's definitely worth buying over the cheaper stuff.

 

Have to ask-- Electric or gas stove? If the former a wire trivet is recommended. I use a 5L "Bomex" with on a electric stove using a trivet. Without it there's far too much stress especially with cheaper glass.

 

Stupid question, this borosilicate glass(I have a Pirex Erlenmeyer) allows to be suddenly cooled after boiling or it behaves like regular glass?

 

I'm pretty sure you're not supposed to be using an electric stove. Flame = OK, electric = not OK. Just searched and found this.

 

Even within the Pyrex brand, there are different levels of quality to the glass that makes it more resistant to high temperatures. However, even Pyrex can develop small micro-cracks over time due to exposure to extreme temperature swings. Sometimes these hidden flaws in an old glass apparatus can cause it to crack later on, even though it is not exposed to an extreme temperature swing at that time.

See http://www.snopes.com/food/warnings/pyrex.asp

 

This will happen. It's the nature of heat resistant glassware. I had a 5L crack along the bottom on me and that was it. Flasks are cool and what not, but they will eventually fail and usually at the worst time. That's when I turned around and started pressure canning my starter wort - mason jars are cheap! And these days a large pressure canner can be had for ~$80-90.

Plus it's a fuckton faster to prepare a starter that way.

The Starter Made Easy

 

I had an off brand flask that cracked the very first time I heated it. No more off brands for me. Just Pyrex and Kimax.

 

I think many people just like saying, "Erlenmeyer"...it conjures up images of white lab coats and mad scientists/homebrewers.

 

That is why they make round boiling flasks.

Didn't anyone learn from Walter White?

 

Speaking of this, I just got a real deal stir plate (I work for a biotech company) and wasn't sure what temperature anyone keeps theirs at when they are doing a yeast starter?

Thanks.

 

Or Heisenberg.

 

I make big starters. I typically use the big-ass 5000ml flasks (or an actual carboy when making lagers). I buy the cheapo flasks ones from homebrew suppliers, and they aren't borosilicate glass (Lab grade flasks are very expensive). I have used the same procedure for many years and haven't had any problems since adopting it. Basically a double-boiler technique.

Put the water and extract in the flask.
Put the flask in a large kettle.
Add water to the kettle to about the same level as the water in the flask.
Put some aluminum foil over the flask opening and lid on kettle.
Heat large kettle to a boil.
"Steam" starter flask for about 30 minutes or so (measure temperature of starter liquid to ensure it's sanitized).

Once sanitized, if you want, you can slowly add water/ice to the kettle to reduce temperature of starter to fermentation temperatures.

 

Given a starter has a much smaller volume of fluid and constant or near-constant agitation, is there some reason you'd need to bother with temperature control, given an average room temp of 70F?

 

My understanding is that borosilicate glass can be rapidly cooled (for instance, taking it directly from the stovetop and partially submerging it in cold water) without breaking, unlike normal glass. Obviously, as the OP learned, even borosilicate glass is not indestructible, but at least it is intended to be used in this way.