How to prevent explosive boiling?

Last year we installed an under-sink water filtration system. Ever since, when boiling water on the stove for pasta, we’ve noticed that the transition from “not boiling” to “boiling” seems to happen rather suddenly. I know this to be superheating, likely due to the filtration of particulates that would otherwise serve as nucleation sites and enable a gentle, gradual transition to a full-on boil.

This had been merely an intellectual curiosity - until yesterday, when it happened so violently that it almost put me in the hospital. In the space of a second or so, the water transitioned from quiescence into a boil that was stronger than you’d ever see with the burner at max heat; the lid lifted, and 1/3-1/2 of the water from the pot ended up on the stove, counter and floor, with some of it spraying the backsplash. It was pure luck that the way the lid intially lifted meant that the backsplash got splattered instead of me; I jumped out of the way of the cascade of hot water that came down the front of the cabinets, and managed to escape unscathed.

Now that I know how dangerous this really can be, I need to sort this out so my dinner doesn’t scar me for life. How can I prevent this from happening in the future? Decades ago in chemistry labs, I recall using boiling chips in test tubes for the same reason. Would one small chip be enough for a big pot of water? I saw one site that said you can’t reuse boiling chips because the air in the pores gets replaced with water. But wouldn’t that water evaporate out after the chip sits in a drawer for a day or two? If not porcelain chips, what else could I use? A few shakes of pepper flakes? A squirt of unfiltered tap water in the pot? Harsh language?

Popsicle sticks or something equally textured.

I bet scratching the bottom of your boiling pot with some coarse sandpaper to create burrs would help. Pretty easy to try, anyway.

We didn’t reuse boiling chips because we were worried about contamination. I always assumed their value was from edges rather than trapped gas.

But regardless, a wooden spoon seems easily retrievable.

I’ve always seen that putting a wooden skewer in a mug of water when microwaving it can stop this from happening in the mug. The above suggestions of popsicle sticks or a wooden spoon should do the trick.

what is the pot made of? Glass? I have your typical stainless steel cookware, and from what I can tell the surface of it provides plenty of nucleation points for vapor bubbles to form. I can’t think of a metal vessel that wouldn’t, they’re not perfectly smooth.

If you’re just making pasta, throw a single noodle in while it’s heating. That should do the trick just fine. When it’s actually boiling, you could take that one out first, but I’d probably just ignore it. I doubt anyone would even notice a single over cooked noodle.

It’s your typical stainless steel cookware. Never had this problem until we installed water filtration.

This seems trivially easy. Will give it a shot and see if we get consistent results. If not, we’ll try the wood stick method. If that don’t work, I’ll see about sandpapering the interior of the pan.

Thanks, everyone, for all the suggestions.

Is the filtration just on the cold water line? I think that’s typically the case with the ones installed under the sink. If so, you could fill the pot with the hot tap, which would bypass the filtration and leave in the impurities.

That sounds terrifying. I’d wear a raincoat or even a tarp or shower curtain liner till you get it sorted out.

The filtered water dispenses from a small auxiliary faucet next to the main one. The main faucet dispenses unfiltered cold and hot water. I could fill the pot from this faucet - but then I’d be using unfiltered water to cook my pasta, which would kind of defeat the purpose of installing the filter. If I were boiling veggies, that’d be less of a concern, but the pasta actually does absorb the water.

Right, it’s the surface characteristics of the boiling chip that provide nucleation sites for bubbles. The concern isn’t that liquid replaces air and prevents it from functioning, it’s that any liquid retained in the chip will mess with the next expirement.

But boiling chips are overkill. The other suggestions of a popsicle stick, spoon, or noodle are more readily available in a kitchen. I wouldn’t recommend scuffing the pot, or you’ll have to worry about food sticking and a challenge cleaning it.

What about adding in a small bit of unfiltered water to the pot? A small amount might allow the water to boil easier but not change the taste

What is in the water that worries you?

Ann Arbor is trying to stay ahead of two particular drinking water contaminants that present a growing threat.

For polyfluoroalkyl substances (PFAS) in drinking water, the EPA recommends less than 70 ppt. The city’s main water supply is a pond north of town, which has recently seen levels as high as 120 ppt. Ann Arbor has set a goal of 10 ppt for treated water sent out to customers, but hasn’t consistently met that.

There is also a large dioxane plume creeping through the ground toward that same source pond. It also comes from other industrial sources in the area, and has in fact shown in treated water sent out to the city’s customers.

While it’s good that the city is paying attention, they’re not infallible, and I don’t want to find out after the fact that they’ve screwed up. There’s plenty of precedent for that sort of thing.

When I was a kid in the Twin Cities, I went through this drinking water catastrophe, in which very high concentrations of industrial solvents were discovered in our treated drinking water.

More recently of course is the famous case of Flint, which was sending out heavy-metal brew without knowing it (and after the knew it, actively trying to hide it) for quite some time.

As for the explosive boiling problem, last night I tried putting a single strand of spaghetti in the water when I turned on the heat. Sure enough, the transition to full boil happened very gradually, just as it used to. So for N=1, my success rate is 100%. :grinning: If this works a few more times, I’m prepared to say it’s a reliable solution. Joey P, thanks. :+1:

Cooking pasta for science!

I too am curious about @filmore’s suggestion of just putting a hit of unfiltered water in the pot, like 1-2 seconds worth.

I also wonder if it’s really worth being concerned about the water pasta is boiled in. You mentioned vegetables as being of little concern, but I doubt the amount of water absorbed by pasta is significant when you’re talking about water that’s only a little bit out of spec. Rice might be more of a concern since it absorbs water in about a 1:1 ratio (you generally add about 2x as much water as rice and half of that water boils away). Plus, might some of those chemicals boil off, or be otherwise neutralized by the heating? I haven’t had a chance to read your links. I suspect you should be more concerned drinking the water straight, or using it for soups, but not so much for something like pasta, especially if you only add a little bit to enhance (de-hance?) the boiling.

I wouldn’t want to cook pasta in potentially contaminated water. Ick! FWIW, I have no particular concerns about my water supply, but I always fill the pasta pot with cold water because I don’t trust what might be leaching off the inside of the hot water heater, or collecting there.

The single strand of spaghetti sounds perfect for pasta. If I were the OP, I would invest in some popsicle sticks so I’d have something to toss in the pot if I were cooking veggies for someone who has celiac disease, or just in general to have a clean item to use when boiling water. In fact… I bet a toothpick would work, although maybe that’s too small, and there’s a risk someone could eat it. Or – I have a ton of bamboo and wooden chopsticks lying around. I bet a 3 inch chink of one of those would be perfect.

Typo noted. :wink:

Damn! I would fix that if I could. I wish they’d enable editing.

I apologize if I offended anyone with that typo, it was certainly not intentional.