Is my home carbonation device a death trap?

June 23, 2017 1:55 AM

The BBC reported today that a whipped cream canister exploded and killed a French woman. At my house we use a somewhat-similar device that makes water bubbly. Help me, seltzer engineers, to assess what we should do.

The canister which killed the French woman looked like this. I read in a French consumer magazine that French whipped cream canisters have seriously injured people before because of defective plastic tops made from high-density polyethylene and the French consumer protection organization is recommending that if you aren't sure what your canister is made from, you should quit using whipped cream canisters with plastic tops.

I got a bottle last month to make seltzer water and this is that model. It seems really sturdy, but it does have a plastic top.

In the hopes that an archaic-soda engineer type haunts the hivemind, my questions are:
--Is a soda siphon similarly dangerous to a whipped cream canister? They seem to have slightly different shapes and they use different gases (CO2 for the seltzer, nitrous for the cream)
--Which part of the bottle flies off? I still don't understand that part.
--Is there a soda siphon safer than the one we've got? (I was wondering about this one, which looks like its charger holder might be metal.)

Yes, we could get a big fancy seltzer machine, or drink La Croix/tap water/etc but we would love to make the soda siphon work if we can.

posted by hungrytiger to Food & Drink (13 answers total)

Is a soda siphon similarly dangerous to a whipped cream canister?

Pretty much. Neither will normally explode.

The siphon you have is probably a bit safer than the pictured whipped cream dispenser because the plastic top is smaller, meaning that the force trying to tear the top off the container at any given internal gas pressure will be lower; I would also expect the smaller diameter threaded neck to be a bit more robust.

If I wanted to make my whipped cream dispenser or soda siphon explode, what I'd do is make the top out of a thermoplastic that would creep under stress, then I'd ignore the condition of the neck seal and keep screwing the top down tighter and tighter and tighter each time I used it, in order to prevent leaks as the rubber ring ages and hardens. That way, I could crush the aluminium neck and/or stretch or destroy the plastic thread and/or crack the top, any of which might eventually be enough to make the thing let go under pressure.

they use different gases (CO2 for the seltzer, nitrous for the cream)

Not really relevant. Nitrous is a strong oxidant and carbon dioxide is inert, but I would rate the chance of a chemical explosion being involved in this case as negligible. There's more than enough straight-up gas pressure inside either of these devices to do some pretty serious damage to any body part that gets in the way of the top if it blows off.

I was wondering about this one, which looks like its charger holder might be metal

I would be very surprised indeed to learn that the injury was caused by the charger holder blowing out rather than the main lid blowing off. The force acting to blow apart any of those joints is proportional to the internal gas pressure and the cross-sectional area of the outer part's aperture, and the latter is smaller for the charger holder than for the main top joint in your siphon and way smaller than for the main top joint in the exploding cream whipper.

If you're concerned, get in the habit of using the thing in such a way that your head is not in the way of either the top or the charger as you screw the holder down to crack the bulb seal. Also try not to leave the canister sitting around under pressure for extended periods.
posted by flabdablet at 3:32 AM on June 23, 2017 [6 favorites]

Those things have been used for so many years that statistically it was inevitable that someone would die from making whipped cream -- especially when the parts went from being all metal to plastic.

The risk seems outsize because DEATH! but you're probably not going to end up slabbed because of your water bubblifier. :7)
posted by wenestvedt at 3:47 AM on June 23, 2017 [3 favorites]

This happened once, out of the hundreds of millions of times that people have used things like this to make whipped cream and seltzer. You're more likely to be struck by lightning while yodeling Wagner's Ride of the Valkyries. The best thing you can do for your health in this situation is to not spend another second worrying about it.
posted by Anticipation Of A New Lover's Arrival, The at 5:18 AM on June 23, 2017 [13 favorites]

It - as in exploding siphons, not deaths - has happened more than once, according to The Guardian:

about 60 reports of exploding siphons causing injuries ranging from broken teeth, tinnitus, multiple fractures and, in one case, the loss of an eye.
[...]
The problem affected more than a dozen models produced between 2009 and 2013, the magazine said, [but] dispensers made after 2015 appeared to be safe

posted by EndsOfInvention at 5:36 AM on June 23, 2017 [3 favorites]

then I'd ignore the condition of the neck seal and keep screwing the top down tighter and tighter and tighter each time I used it, in order to prevent leaks as the rubber ring ages and hardens.

Not quite at the point of having to screw the top tighter and tighter each time but holy hell, off to buy a new rubber ring anyways.
posted by vignettist at 8:08 AM on June 23, 2017 [1 favorite]

I've no official training with regard to pressurized gas safety - but I have worked with compressed gasses in a lab environment for years, I have a 20lb CO2 tank in my kitchen that I use weekly to make soda water, and I've had one plastic 2L bottle catastrophically explode on me while shaking it. (It split along its length, with no obvious regard for orientation. I had bruises on my arm, but nothing more serious. I was wearing safety glasses.)

The best advice I'd offer is to wear shatter proof safety glasses and keep the vessel as far away from your body as is reasonable. A failed plastic pressurized vessel could kill you, but it's far more likely to blind you. Compared to things most of us do every day - riding in cars, eating food prepared behind closed doors, entering a swimming pool - a life threatening explosion of a consumer compressed gas device is pretty far down the list of things we should be frightened of.
posted by eotvos at 8:42 AM on June 23, 2017 [1 favorite]

a SodaStream is really only marginally bigger than what you're already using, and you don't have to worry about this kind of thing. They take up very little space, use no electricity, and work great.
posted by cakelite at 8:56 AM on June 23, 2017

I have a 20lb CO2 tank in my kitchen that I use weekly to make soda water, and I've had one plastic 2L bottle catastrophically explode on me while shaking it.

My dad built a rig like that when I was a kid. His was based on a copper tube epoxied into a hole through the plug-type internal screw stopper for one of the refillable glass soft drink bottles that were the style at the time.

Dad was a high school chemistry teacher. He never wore eye protection or even long sleeves while shaking the crap out of one of those things. He did wrap them in a towel beforehand, though I don't know whether that would actually have contained the shrapnel if one had in fact exploded.

Pretty sure the CO₂ he bought from CIG wasn't food grade either.
posted by flabdablet at 10:27 AM on June 23, 2017

People saying it only happened once should perhaps read a different article, which points out there have been several serious, permanent injuries. Sixty accidents with serious injuries in seven years, according to that paper's study on that time period. Lost eyes, broken teeth... Another woman they spoke to was in a coma for five days and had to have two operations to save her life.
posted by fraula at 11:54 AM on June 23, 2017 [3 favorites]

The siphon in the fatal accident was a model that had been recalled in 2013 because it was known to be faulty. If you have concerns about the particular siphon you have, look to see who (actually) made it and whether any accidents have been reported. It looks like that particular product was sold by at least fifteen different brands from 2009-2013. If yours wasn't in that range it should be safe.

I have two iSi siphons (one for whipped cream, one for seltzer) and I believe them to be safe. iSi did have a safety recall for its "Twist 'n' Sparkle" line with plastic bottles, because the bottles could fail catastrophically. I'm pretty sure if their metal siphons were similarly unsafe there would have been a similar recall. So if you want to be sure: buy a siphon from a reputable manufacturer whose products can be traced and who has a record of safety.
posted by fedward at 3:02 PM on June 23, 2017 [1 favorite]

Not quite at the point of having to screw the top tighter and tighter each time but holy hell, off to buy a new rubber ring anyways.

I think flabdablet is right on here - this is vanishingly unlikely to happen with reasonable maintenance and inspection. I mean, nothing special, but when the ring looks or acts worn, replace it instead of making it work, keep gasket seating surfaces clean and scratch/dent-free, look over the threads of the fastener for wear/damage/cross-threading. Most threaded fittings are not supposed to need gronking on, just firm tightening. Even your garden hose probably just needs a new seal ring when it leaks, not star torque. I almost (I wasn't there, I guess) guarantee that French woman's canister was tightened too tightly for those plastic threads, over-stressing them even before the gas pressure was applied.
posted by ctmf at 3:40 PM on June 24, 2017

OK, things similar to this have happened more than once. You're still more likely to die from a cuticle infection caused by dropping a can of baked beans on your big toe.
posted by Anticipation Of A New Lover's Arrival, The at 5:56 AM on June 26, 2017

I mean we are not even close to "struck by falling coconut" levels of things to worry about, here.
posted by Anticipation Of A New Lover's Arrival, The at 5:57 AM on June 26, 2017