Warning! Flask Volcano!

First off, let me admit to not being the most careful person. Secondly, high school chemistry was about 20 years ago!

Here's what happened. I was boiling my wort in my 2L flask. I had about 1L of wort over a gas burner on fairly low heat. I expected a bit of foam up and even some boil over. I had used a sanitized baster to stir things up, as a spoon didn't really fit. As it was starting to boil, I stuck the baster in to mix up the wort a bit. I sucked up some and immediately squirted it back in. I was very quickly bathed in steam and flying wort. Luckily I'm used to doing dumb things and hurting myself, so other than some minor burns to my hand and a hell o f a mess in the kitchen, it turned out okay.

What happened here? I'm sure it's a simple stupid mistake, but I'd like to keep other folks from having to experience this.

Thanks!

Fermcap - FWIW

use a small amount to prevent boilovers in the flask and boil kettle and to prevent blow-offs in primary.

The number one rule of boiling crap in an erlenmeyer flask is, don't put stuff in there once it's hot.

You create a nucleation point for the bubbles, and the shape of the flask literally funnels everything up and out of it.

The wort was heated to above it's boiling temperature and when you disturbed it with the baster you broke the surface tension that was inhibiting the boil and it erupted. This is a fairly common phenomenon and happens a lot with microwave ovens when boiling water and heating some foods. I had it happen once when adding yeast nutrient to the wort in a flask. Just the addition of the tiny bit of nutrient triggered a volcanic reaction. I won't be doing that again anytime soon. You can boil up a full two liters of wort in a two liter flask if you are careful and use some foam control. Heat it slowly and reduce the heat as you approach the boiling point. Keep a close eye on it and be prepared to remove the flask from the heat if it looks like it's going to get out of control. A boil over can happen quite suddenly and even more so if you disturb the wort or add something like I did. There are two factors involved and either or both can create the volcanic effect. One is the surface tension of the liquid and the other is the nucleation points where the vapor bubbles form. When I added the nutrient it acted as the nucleation points and triggered the sudden steam release. You apparently broke the surface tension with the baster with the same result. The nucleation thing is well demonstrated with the Mentos/soda bottle trick that you have probably seen on Youtube or TV. The addition of the Mentos creates the nucleation sites for the sudden CO2 release and the subsequent fountain of soda. A friend of mine got blasted in the face when his poached egg exploded as he opened his microwave and poked the egg. The membrane over the yoke was holding back the explosion until he poked it. Whammo!
Talk about egg on your face! lol...fortunately he was not injured with the exception of some very minor burns. Could have been much worse if he had been hit in the eyes with very hot egg yolk.

A similar but opposite reaction happens with very cold things... works great with corona bottles, because they're clear. Leave a corona bottle in the freezer until you're sure it's been in there long enough to freeze. The beer is very well filtered and will go below freezing temps without freezing due to the lack of nucleation sites. Open the beer, add a drop of pretty much anything, and you can watch the whole thing freeze in a few seconds... its very cool to see the ice 'wave' travel down the bottle. Of course, now you have frozen beer, not a great thing, but its a neat trick.

Thanks guys! I kinda figured it was something like that, but I appreciate the great explanations. Would fermcap really stop such a thing? I have no experience with it, but I may give it a try. Thanks again!

Fermcap will help with boilovers.

Once, I forgot to add my stirbar to the flask and decided to add it after the starter had reached boil. Even with Fermcap, I had an enormous boilover.

Like wierdboy said, never add anything to the flask when it's hot.

OCLemon said:

A similar but opposite reaction happens with very cold things... works great with corona bottles, because they're clear. Leave a corona bottle in the freezer until you're sure it's been in there long enough to freeze. The beer is very well filtered and will go below freezing temps without freezing due to the lack of nucleation sites. Open the beer, add a drop of pretty much anything, and you can watch the whole thing freeze in a few seconds... its very cool to see the ice 'wave' travel down the bottle. Of course, now you have frozen Skunk water, not a great thing, but its a neat trick.

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Nothing else to add but I had to fix that for you...

A chemist would drop crushed porcelain into the flask to provide nucleation sites. A broken clear glass marble/decorative stone would accomplish the same thing. Alternatively, if you have a teflon stirbar, you can drop that in to encourage an even boil.

Same as Hugh Jass, I made a similar mistake by dropping my stir bar in after the boil started to sanitize it. Nucleation site created, wort volcano. No burns but my hands hurt from all the scrubbing I had to do on the stove.

Bobby_M said:

Same as Hugh Jass, I made a similar mistake by dropping my stir bar in after the boil started to sanitize it. Nucleation site created, wort volcano.

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Yep, been there as well. Never, never put anything into the flask once it has started boiling.

I don't really think fermcap will help here as this was not a standard boil over. With pyrex glass with no flaws, there is no place for bubbles to form, so water keeps absorbing heat and when the point is created, it explodes. My suggestion would be the use a wooden skewer, which is essentially what we use in the lab as a "boiling stick" to prevent just this problem.

FermCap-S forever.

My stirbar goes into the flask before the boil. Never a problem. It won't melt.

That's why I never boil in a flask, hot wort hurts.

I did this today. I put a funnel on top of the flask and went to add the dme and it went everywhere. I've been bathing in aloe all day. I thought it was caused by me completly clogging the opening. No? the funnel is in and the DME clogs the funnel, where is the steam to go? It just blows!!! Is the trick to add the DME before the boil starts? can you add it before you even start to heat the water?

Are these volcanoes occurring only while it's boiling? Could you remove the flask from heat for 10 seconds or so, until the wort is visibly calm, then add whatever you need to add, or is it still going to happen at 209F or so?

I boil my stir bar in the flask with a little bit of water.
I let the escaping steam sanitize the foam filter at the same time.
I boil the starter wort in a sauce pan and pour into the sanitized flask.

I have boiled in my flask twice. I place my probe thermometer in the top and the stirbar is in place for sanitation. Once I get to a boil I pull the thing off heat and begin to cool.

I'm sure it's not a long enough boil to sanitize everything, but I'd rather risk sanitation than boil my skin.

mdillon20 said:

I did this today. I put a funnel on top of the flask and went to add the dme and it went everywhere. I've been bathing in aloe all day. I thought it was caused by me completly clogging the opening. No? the funnel is in and the DME clogs the funnel, where is the steam to go? It just blows!!! Is the trick to add the DME before the boil starts? can you add it before you even start to heat the water?

Click to expand...

I add the DME to the flask before adding the water. Simplifies the procedure quite a bit.