Yeast Washing, boiling water explosion

[mcelrokj]

I had quite an interesting experience with my 2L Erlenmeyer flask today. I was brining 1250mL water to boil for some yeast washing later today. I used my gas stovetop as usual. But I noticed the water acting funny this time around. Instead of coming up to a rolling boil, I saw single eruptions of boils every 10-15 seconds or so. Now, I consider myself fairly smart, so I decided it would be a good idea to take a few steps back and watch from afar. Thankfully I did, because after about 45 seconds of nothing, a huge explosion of boil erupted, shooting half of the boiling water up to the ceiling and about 3-4 feet out into the kitchen. Luckily no one was scalded.

Any chemists out there with an explanation as to why this would happen? I typically boil wort in the flask for starters, but I have boiled just water before without any issues like this. The flask was cleaned prior with soap and water, but should have been squeaky clean and I used water from the fridge filter.

Thanks for the help!

 

[aiptasia]

Something residual in the water? I don't use soap to clean glass as it can leave residuals behind that can wind up in your beer. I'd suggest using oxyclean free or PBW for your cleaning. It washes out cleaner without residual crap left behind.

 

[mcelrokj]

Something residual in the water? I don't use soap to clean glass as it can leave residuals behind that can wind up in your beer. I'd suggest using oxyclean free or PBW for your cleaning. It washes out cleaner without residual crap left behind.

Thats a good point. I have OxyClean sitting on the shelf, I just never thought to use it for the flask. The residual soap must have caused some increase in surface tension, preventing the release of steam, and building up pressure until... BOOM! Sounds like a reasonable explanation to me.

 

[Coff]

Wow that's scary, glad nobody got hurt.

 

[masonsjax]

Sounds to me like it was too clean. Boiling water likes to have nucleation sites for the bubbles to form, if there are no imperfections in or on the glass to serve as sites, you can get violent explosions. I've seen it happen in the microwave. Water comes out still as glass but as soon as a spoon breaks the surface... boom!

 

[mcelrokj]

Another thing I noticed that I had done differently was that I was not using a thermometer. The second time around, it started to boil, but still seemed a little off. When I added a thermometer in, it seemed to break the surface tension and allow the water to boil more freely.

(which seems to confer with what masonsjax said)

 

[pelipen]

Were you using fairly pure water? What masonsjax wrote is correct. It is very possible to super heat water in very clean smooth glassware. As soon as there is a nucleation site, fwooosh, water everywhere. In labs they use boiling chips for this reason.
If it's a problem with your setup, introduce a small marble, grain kernel, aquarium rock, etc.
I once had a toluene solution blow up at me when I thought it was cool enough to add a chip. Nope. Stupid mistake on my part.