Erlenmeyer Flask on Electric Stove

[hampshirebrewer]

I add boiling water to my DME & yeast nutrient in the flask and whirl to dissolve. I simmer it on my backpacking stove for 15 minutes. 2 liter flasks cost too much to risk on stove elements or other hard surfaces.

Plunge it (gently) with oven baked foil krinkled on top into a cold water bath for 15 minutes. Pitch yeast and grow it. I use a rubber band to hold foil on and prevent critters (mice, cats, bugs) from finding their way into my starter wort. Whirl frequently and if time permits, settle yeast in refrigerator or cold cellar overnight so I can decant most of the spent wort before pitching. I sanitize with star san and no longer flame edges.

A 1.2 liter starter of XL Wyeast 1056 started pushing air through the airlock of a 1070 IPA this past weekend in under two hours. YMMV

 

[CantWinThisGame]

In all my chemistry labs in college where we did experiments using borosilicate or pyrex flasks, we frequently brought them directly from flame and boiling to a cold water bath. Some of the chemicals we used boiled at MUCH higher temps than water. If you are boiling wort in a flask, the highest the temp can get is only around 220'F (remember it's mostly water, and sugars will elevate the boiling point slightly). I can't remember a single flask breaking from going directly from very hot to a cold bath.

 

[day_trippr]

Greetings, CantWinThisGame, and welcome to HBT

There's a significant difference between heating with flame vs contact with an electric element (the topic) and that's not even considering lab grade glass vs what most of us peons obtain.

imo, putting an e-flask in direct contact with an electric range element never a good idea...

Cheers!

 

[Broothru]

Greetings, CantWinThisGame, and welcome to HBT

There's a significant difference between heating with flame vs contact with an electric element (the topic) and that's not even considering lab grade glass vs what most of us peons obtain.

imo, putting an e-flask in direct contact with an electric range element never a good idea...

Cheers!

There's actually different grades of borosilicate. The type you used in high school chemistry class was likely "academic grade". The kind used in universities, hospitals, research facilities and commercial labs is "scientific" or "laboratory" grade.

Academic grade often has minute flaws and may or may not crack under direct heat or shock cooling. Laboratory grade is essentially without flaws. Academic grade is either manufactured to lower standards or is culled from lab grade rejects.

I've got lab grade 1 liter and 2 liter Erlenmeyer flasks and 1 academic grade 5 liter flask. The 2 l flask was 3x times as expensive as the 5 l. Needless to say, the 5 l never sees any use other than on the stir plate. I did crack a 1 l flask once on an electric coil element while boiling some wort. Huge mess. Even with lab grade gear, I still use a 3 quart sauce pan to boil, plus the borosilicate takes forever to come to a boil in my wife's induction cooktop.

 

[Jtvann]

Welcome back to life 10 year old thread.

I was lucky enough to crack a 5L flask on an electric stove top. 3.5L of boiling hot sugary liquid rushing out all over everywhere will make you snatch a child off the floor real fast. Never again.

I think the problem with electric coils is that the coil gets super hot where it contacts the glass, separated by unheated areas, followed again by super hot spots. This uneven heating is the problem. Any flame type heating heats very evenly. Theres no super concentrated area of heat. Putting on a flat cast iron, or other heat conductive surfaces works well as long as the flask sits flatly against contacting the entire surface area.

Working with glass, if it hasn't broke yet, it's just that ... yet

 

[day_trippr]

That is exactly the problem, and unequal thermal expansion can be catastrophic wrt glass.
It's also why the bottoms fall out of glass carboys...

Cheers!

 

[Dog House Brew]

I have a few 5L flasks and boil in a pot and pour in. My mother has made hot water for her tea in an old Pyrex coffee pot. She uses a trivet that was made from a cloths hanger. Never an issue. I’d love to boil and cook in my flash using my electric stove. I made a trivet and did one in my small 2L flask. The mess would be terrible. Guess I need to brave it

 

[day_trippr]

Take pictures!

I don't get it. Sheer laziness to clean a pot (takes 20 seconds) doesn't explain the propensity for folks to take stove top risks with e-flasks...

Cheers! (Y'all must be single...and not have Spousal Wrath to think about )

 

[Hwk-I-St8]

I just tried this today. I did take the flask off the burner and put it on a cool area of the stove for a minute. From there I put the flask in cold water in the sink on top of a small cooling rack and let it sit for about a minute before adding ice to the water. So far, so good!

Also, I have a small wire heat spreader that came with my Yama Vac Pot. This is very similar to modifying a wire hanger and putting it on the stove. (I've done that, BTW, and the hanger had a coating that burnt off onto the stove and was a really a ****** to clean off). I used the wire piece under the flask just in case. Although from what I read in this thread I don't think this is required on a ceramic smooth top electric stove, I guess it put me at ease so I am going to continue to use this as a precaution.

When I was listening to the Brew Strong episode on Starters the other day I picked up a great tip. Instead of adding DME directly to the flask, they recommended turning the heat off, dumping the almost boiled water from the flask into a metal bowl and using a metal whisk to stir in the DME and yeast nutrient if you're using it. I used a heat mitt when handling the flask as to not burn the hell out of my hand. After that you can use a funnel to pour the mixed solution back into the flask. I added some firmcap-s to the flask and this worked beautifully!

If you're going to go to that trouble, you might as well do what I do, which is make my starter in a sauce pan and then just use a funnel to pour into the flask when done. I really did not want wort burned onto my glass top stove at my old house and it would be as big a mess or bigger on the gas cooktop at my new place. I figure the flask will fail eventually and it's most likely to happen when heating or chilling. My flask is always in the sink when it gets wort, so if it fails, it'll be an easy cleanup.

 

[Dog House Brew]

The risk of spouse grabbing a bat while I’m sleeping is exactly why I use the pot and pour method.

 

[w8av]

If you're going to go to that trouble, you might as well do what I do, which is make my starter in a sauce pan and then just use a funnel to pour into the flask when done. I really did not want wort burned onto my glass top stove at my old house and it would be as big a mess or bigger on the gas cooktop at my new place. I figure the flask will fail eventually and it's most likely to happen when heating or chilling. My flask is always in the sink when it gets wort, so if it fails, it'll be an easy cleanup.

Just to weigh in on this from my college chemistry years (I have a chemistry degree), you should never expose the flask to an open flame. If you are going to use an Erlenmeyer flask on a concentrated heat source (a flame, an electric stove with a coiled burner, etc.) you should consider purchasing a wire gauze. You can get them from any lab supply house, like Fisher Scientific. They are pretty inexpensive and are good insurance They spread out the heat and the center of the wire gauze contains inflammable material that keeps the heat source from directly touching the flask. I use one here when making my starters. I too then set the flask aside for a minute or two after the boil of the starter wort is done to do a slight cool down and spread t he heat out a bit more evenly across the surface of the glass before putting it in a cold water bath.

With a glass cook-top surface, you will probably be OK without the wire gauze since the glass spreads out the heat a bit more evenly than a coiled burner.

 

[Dr_Jeff]

I use a $20 dollar hot plate from walmart that has a cast heating element on top and it has worked fine so far. I have avoided using my glass cooktop stove and any bare element. For $20 you should be safe going this route.

^^^^^^
This

That way you have "your" electric eye in your brew area, away from "her kitchen", I made a mess once and heard about it for a long time. Likely the best twenty bucks I ever spent. It's easy enough to empty the ice into a plastic pan or bucket and carry it to your brew area. I've had boilovers on my electric eye, but it was "my mess" and not in the kitchen. I've since put down a couple of ceramic tiles below, the little electric eye, and it is one of the types with the cart iron elements.

I'll take a ceramic tile and put it into the bottom of a five gallon bucket, put in the flask on the tile, and pour in ice and water.

BTW - I cracked a five liter flask about the second or third time I used it on an electric eye stove, while it was heating, no messes, just a big crack, across the bottom and up one side. F*ck, f*ck, f*ck.

 

[Broothru]

^^^^^^
This

That way you have "your" electric eye in your brew area, away from "her kitchen", I made a mess once and heard about it for a long time. Likely the best twenty bucks I ever spent. It's easy enough to empty the ice into a plastic pan or bucket and carry it to your brew area. I've had boilovers on my electric eye, but it was "my mess" and not in the kitchen. I've since put down a couple of ceramic tiles below, the little electric eye, and it is one of the types with the cart iron elements.

I'll take a ceramic tile and put it into the bottom of a five gallon bucket, put in the flask on the tile, and pour in ice and water.

BTW - I cracked a five liter flask about the second or third time I used it on an electric eye stove, while it was heating, no messes, just a big crack, across the bottom and up one side. F*ck, f*ck, f*ck.

I've gone "small ball" on my heating element as well, but decided to go with a portable induction cook top instead. It gets me out of SWMBO's kitchen and into my brew space. It does involve using a conductive sauce pan, but, "So?"

One quart of water comes to a boil in less than 90 seconds and can be controlled to prevent boil-overs in a second (or less) after adding the DME. The stainless sauce pan goes directly from full boil into a laundry sink with 50F water for quick chilling, then wort goes into an Erlemeyer flask with yeast onto the stir plate. Quick and easy. No breakage.

Plus the portable induction does double duty in the RV when we travel.

Brooo Brother