permo
Well-Known Member
I just bought a 4000 ML Pyrex flask for my yeast propogating ventures. I have the stir plate and all. Now I am wondering if I dare move this thing directly from the stovetop to an ice bath or if it will crack?
4000 ML Pyrex Flask - stovetop to icebath?
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Regulation
Well-Known Member
Pyrex means it should be good to go I do it all the time.
jester5120
Well-Known Member
yeah pyrex is designed to handle heat shock like that but feel free to build the worlds smallest immersion chiller cuz that'd crack me up.
permo
Well-Known Member
This is going to be awesome!
So just to be straight...I can put this thing right on my ceramic cooktop in my house, boil my starter and chill it...all in the same container!? kick arse....
So just to be straight...I can put this thing right on my ceramic cooktop in my house, boil my starter and chill it...all in the same container!? kick arse....
one word of advise, put you stir bar in before you heat. Adding nucleation points once the wort is hot can cause boilovers.
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Personally, I wouldn't start with an ice bath... I'd start with a warm water bath, and keep putting cold water at a reasonable pace and eventually put ice in there. But... that's just me.
Here's a little experiment I did with salt-water. Double-boiling erlenmeyer.
MC
Here's a little experiment I did with salt-water. Double-boiling erlenmeyer.
MC
The thing about boro-silicate glass is that it's perfect right up until the moment it's not! It can take thermal shocks right up until the moment it can't! It can be used directly on a ceramic cooktop without any issues right up to the point that it shatters and spills 4000ml of hot sticky wort all over your stove and kitchen. Don't ask me how I know!
Suffice it to say that I still use my flasks for fermenting the starter on my stir plate, but I no longer use them on the stove. I boil the starter wort in a pan, chill it and then pour it into a sanitized flask with a sanitized stir bar already in there and then add the yeast.
Suffice it to say that I still use my flasks for fermenting the starter on my stir plate, but I no longer use them on the stove. I boil the starter wort in a pan, chill it and then pour it into a sanitized flask with a sanitized stir bar already in there and then add the yeast.
SixFoFalcon
Well-Known Member
Yeah, that's the whole point of getting a pyrex flask. If they weren't suitable for temperature shock we'd all be heating and chilling our wort in a regular saucepot and then transferring it to any cheap flat-bottomed vessel for fermentation with out the expense of buying borosilicate glass.
For peace of mind, I just rinse the outside of the hot flask under tap water for about 30 seconds before plunging it into the ice water bath in the sink, but even that is probably not necessary.
I don't put the stir-bar in until the wort is chilled.
For peace of mind, I just rinse the outside of the hot flask under tap water for about 30 seconds before plunging it into the ice water bath in the sink, but even that is probably not necessary.
I don't put the stir-bar in until the wort is chilled.
johnsma22 said:
This is what I do. I don't trust them not to break.
SixFoFalcon
Well-Known Member
So why are you guys bothering to pay extra money for borosilicate?
SixFoFalcon said:
No I got mine through a homebrew club member cheap. Either way they are great for use with a stir plate due to their flat bottom. I've seen conflicting information on this topic but I have found many sources saying there is a risk of cracking.
I'll save the mess. I also find it easier to boil in a large pot and not have to consider boil over as an issue.
http://www.ehow.com/info_12045341_can-use-pyrex-ceramic-cooktop.html
Because I like feeling like a mad scientist with all the lab glassware and stir plate laying about, lol! I didn't post what I posted because theoretically they can and will eventually break. I posted about what happened to me while boiling a 3L starter on my stove top. I made dozens of starters in that flask, boiling on the stove top then into a pot of warm water to cool, to avoid a severe thermal shock, and then continuing to cool in ever colder water.
I did this without issue until it shattered right in the middle of a boil! I continue to use them for fermenting on my stir plate because I feel they are the best vessel for this purpose.
Just ask any of the members here that work in a lab. Ask them if borosilicate glass flasks are considered indestructible with repeated heating and cooling cycles. At least in a lab there is not the risk of getting 3000ml of hot sticky wort down the sides of your wife's brand new stove!
SixFoFalcon
Well-Known Member
Hey it's all good. I figured it was equipment you already had on hand. I just didn't want a newb feeling like they have to spend $60 on a piece of glass when they could just get a $5 plastic food-grade tub if they had no intentions of ever using the same vessel for heating, chilling, and fermenting.
SixFoFalcon
Well-Known Member
And for the record, I do work in a lab. 
maffewl
Well-Known Member
No scientific evidence here, just personal experience... I've had Pyrex shatter on me from placing directly on the stovetop when cooking corn. I think johnsma22 hit the nail on the head... it's good until it breaks.
bruin_ale
Well-Known Member
I use mine directly on my gas stove, but I don't go directly to an ice bath. I usually let it cool to the point that I can pick it up without a potholder, then run some cool sink water over the sides, then dunk in an ice bath. I figure less thermal shock and I'll have less risk of the eventual shatter. I will continue to heat it on the stove though, I absolutely love the convenience of that - no cleaning a pot, no need to even sanitize the flask because it gets sanitized during the boil by the heat. Boilovers are a non-issue, a drop of fermcap takes care of that.
Just to be on the safe side I take mine off the heat for a couple of minutes. I then put hot water in the pan I will be cooling the flask with, I start cold water flowing then add the ice. This only adds a few minutes to the process and give me peace of mind.
SixFoFalcon
Well-Known Member
The other thing a lot of people overlook is that if you're boiling in the flask and you keep it covered (foil, foam stopper, airlock, whatever) you really don't need to chill it at all. You can just leave it sitting out until it's cool enough to pitch into. It's not like you have 5+ gallons sitting in a pot with a large opening where nasties can get in and you're racing against the clock.
bruin_ale
Well-Known Member
Totally agree, that's why I don't rush it into an ice bath. I just let it chill while I'm watching TV or whatever, if it's late and I want to go to bed or something I'll let it chill a bit and then ice bath to get it the rest of the way there.
wolverinebrewer
Well-Known Member
This is me also. I just don't trust it and it isn't really any more effort to do it this way.
spearko520
Well-Known Member
i just a had a pyrex beaker break. my wife swears that it's because i heat and cool it all the time- i swear that it's because she dropped it. you should get a divorce.
Pyrex isn't necessarily borosilicate glass anymore. It's just a trademark that was sold by Corning 20 or so years ago. I'd be weary about shock-cooling a flask, unless it was made by someplace like chemglass.
permo
Well-Known Member
Man, I was so excited to make my process easier too!
FarmerTed said:
From my understanding, anything designed for the lab labelled pyrex is still borosilicate. All of the measuring cups, casserole dishes, and other kitchen tools are tempered glass, so you need to distinguish between them. My 4 cup Pyrex measuring cup says specifically "Not for Lab Use."
Regulation
Well-Known Member
Borosilicate is NOT thermal shock proof it is RESISTANT ... And if it breaks it is suppose to break into a few large chunks.
Personally I do my starters on my turkey fryer set real low... No mess if it does happen to break. Unless I get real lazy and I'll throw the flask on the stove ... I throw it right in an ice bath too... Just like I would in the lab... Since that IS what it is designed for.
Personally I do my starters on my turkey fryer set real low... No mess if it does happen to break. Unless I get real lazy and I'll throw the flask on the stove ... I throw it right in an ice bath too... Just like I would in the lab... Since that IS what it is designed for.
spearko520
Well-Known Member
that's just because they don't want you cooking meth with it. lousy culinary industry...
