> In tests with mice, however, the animals did not seem to prefer drinking heavy water over regular water, although they did show a preference for sugared water – suggesting that in mice, D2O does not elicit the same sweet taste that people can perceive.
I was reminded that rodents also can’t taste aspartame[1], and that in general human taste buds are more finely-tuned than many other mammals (we can detect isomers and many complex bitter chemicals, whereas many other animals can only do the amino acids, sodium, and simple carbohydrates).
Having never drank it myself I was wondering if the sweet taste of heavy water is distinctly “artificial” in the way that sucralose/aspartame/etc in water is immediately distinguishable from regular sugar.
Huh. So, when Reepicheep in Prince Caspian discovers that the ocean is no longer salty but tastes sweet, we can rule out that the oceans of the far reaches of the world containing Narnia are made of heavy water, because if it were then he wouldn't have been able to taste it.
Though I suppose any fan theory in this direction could be salvaged by the conjecture that talking mice are different.
Wouldn't the olfactory bundle above your nose be a number of times larger than an entire rat's brain? Not to mention everything downstream of it ...
A lot of the smell sensitivity comes from ("carefully tuned?") positive feedback loops int the olfactory systems which amplify small signals.
Or something like that, supposedly. Not my area. At least, not the input side. On the output side of stink, I'm no theorist either; maker, for sure, though!
But this is specifically not smell, or even about the brain: it’s about what chemicals the tastebuds are physically capable of detecting. In particular the sweet taste of heavy water seems to be purely related to the sweet taste buds (though there may be secondary flavors that come from the smell).
Within humans there is considerable variance among bitter tastebuds. Roughly speaking, the salt/sour/sweet tastebuds are comparatively simple ion detectors: salt = sodium, sour = hydrogen (from the acid), and sweet = glucose. And yes, sweet is more complicated, because it’s trying to detect a more complicated form of aquatic solute. But the idea is that these tastes are trying to find a specific and well-defined chemical property.
Bitterness is different. Bitterness is basically a poison detector, which means that to be effective it needs to register a wide variety of potential toxins. So akalais/bases tend to be bitter because naturally-occurring bases tend to be toxic. But there are all sorts of complex organic molecules that may be toxic (or are chemically very similar to toxins), which some people can taste and others cannot. Cilantro is probably the most famous example: people who hate cilantro are tasting a (harmless) toxin that other people can’t detect. But this taste is a true taste from the tastebuds, not a smell.
I was being a bit pithy - the bitter tastebuds are giving a “false positive” and identifying something as poisonous when it isn’t (not to humans anyway - linalool, the major flavor oil in cilantro, is an insecticide, and not very healthy for many other mammal species).
Possibly there is a dangerous chemical out there found in berries/leaves/etc which is structurally similar to linalool, enough to fool certain types of bitter tastebuds.
Personally I can pick out ingredients and tasting notes better than most of my friends and I have almost no sense of smell. Although I think in general smell is supposed to dominate taste, blocking your nose when you eat has a strong effect on flavors or something. Doesn't affect me much.
As a kid, I used to get stomach aches and a long list of other issues. Fast forward after a bunch of tests as an adult and the results reported to me by a doctor spelt out that most artificial sweeteners are effectively poison to me. If I want a headache, stomach ache, etc I just consume one of the many sweeteners out there.
The "hyper-sweet" taste and after-taste I get from most artificial sweeteners for me is a signal of poison or bad food. Its a clear signal to avoid that food in future.
My question is the same: I wonder if D2O would have that same kind of "twisted" sweetness?
Secondary questions: I wonder if our ancestors did the same? Noticed that they didn't feel well and that was enough to tip the selection balance such that we now have the ability to detect D2O? How subtle would that effect be? or is just it tied into a specialised "anti-poison" set of structures we've got to detect bad-food? I think this is more likely. D2O is bad water. We have senses for other kinds of bad water as well.
I think, it's sort of a side effect. The ancestor's taste buds were optimized for giving them better chances of survival, and one feature was better detecting of sweetness. D2O didn't exist then and so couldn't influence survival, so detection of D2O is just an accident.
Then it went to him recollecting the heavy water that has passed through him. Which is very Cody, but also, well, gives off strong Howard Hughes vibes.
Cody is a heck of a smart person, but then does some pretty questionable stuff. His mercury vids are a good example. Like, I believe him when he says that if you don't have open wounds, you can slosh mercury about in your mouth safely. But for the life of me, I just can't think it's actually safe.
Or the time he was sweeping the center median of a freeway at night trying to collect platinum dust from catalytic converter exhaust. Yeah, it was under the lights, but daytime would obviously have been better.
Or his noble gas vids. Inhaling them seems safe per his description, but the vibe is just so, well, not safe.
A lot of his vids are like that. It feels very early-1800s-chemist, back when they had to taste all the reactions cuz they didn't have pH paper. Like, it all has to be sensorial for him/the views.
I never put mercury in my mouth but I played with it with bare hands quite frequently as a kid. It's dangerous if it gets hot and you breathe in the gas or if you drink it or get it in an open wound, but I always avoided those things. Lead's the same way: Hold it in the hand, don't ingest it, wash your hands afterward and there's nothing to worry about.
Some of his really cool videos I think were taken down (making yellowcake, his mining series, surgically implanting a magnet into his finger to feel magnetic fields)
This site [1] maintains an excellent backup of Cody's body of work. I also personally make a similar archive available on Soulseek. Hope that helps folks interested in seeing that content!
Not mentioned in the piece is that a small fraction of naturally-occurring water is "heavy" for a somewhat different reason. Oxygen as well as hydrogen has stable isotopes, O17 and O18.
Summary of O16, O17, O18 formation inside massive stars, here:
The explanation may have something to do with an extra neutron roughly doubling the mass of a hydrogen atom, whereas two extra neutrons raise the oxygen mass by only 2/16ths or 12.5%.
Was the O18 water also extracted from a cascade of electrolysis cells? If so, was it extra low in deuterium?
My understanding is that, at least during WWII, Norway had a bunch of hydro power they used for electrolysis to produce hydrogen in order to produce ammonia via the Haber process. Deuterium is accelerated about half as strongly as regular hydrogen in the electrolysis cells. If you connect up your electrolysis cells in series, the small gradient in hydrogen isotopes you get across each cell accumulates across the cascade, and also the regular hydrogen leaves as a gas at a higher rate. At least that's my understanding, which would also imply the end of the cascade that's depleted of deuterium is also enriched in heavy oxygen isotopes.
Unrelated to water heaviness, while not the hardest, NYC tap water always tested sweet to me. I love that taste. It's amazing how used I got to it, to the point that drinking tap water anywhere else feels like some sort of punishment. It really made me realize after living outside of NYC how infrequently New Yorkers actually buy bottled water.
BTW: "New York City department of environmental protection is one of the 5 municipalities in the US that is allowed to supply unfiltered water based on their water quality, and the water is well known for its fresh taste (which is based on the absence of chlorine, a chemical often used for water treatment)."
NYC tap water is astonishingly good. Not just better than you'd expect for a big dirty city, but better than you'd expect from a pristine mountain glacier in Norway. It's because of those giant underground tunnels that bring in the water fresh from far away in upstate NY. It's the best tap water I've tasted in the US.
I've always found Boston tap water to be excellent too. It comes from the Quabbin Reservoir in central Massachusetts, and is a claim-to-fame for Sam Adams beer. They even mimic the water in their breweries elsewhere.
In general mountain water I think is the best.
People don't really think about it this way, but New York is actually very close to two mountain ranges (the Taconic range of the Appalachians, and the Catskills). The Taconics are the dramatic peaks you see when crossing the Hudson a bit further north around Newburgh, and the Catskills are the much larger mountains slightly more inland.
I couldn't wrap my head around how such a polluted city could have such clean water and found this:
"New York City drinking water springs from 125 miles away in the Catskill Mountains -- 90% of the water comes from the Catskill/Delaware watershed, where waters from tributary rivers collect in 19 reservoirs. The other 10% comes from smaller watersheds in Westchester and Rye -- all of it traveling through vast underground aqueducts to supply the city’s residents."
While growing up in a very dry region in India, I remember people get boring wells drilled in their land to extract ground water (sometimes even 1000 feet deep). This ground water often tastes subtly sweet and I remember drinking that water in summer heat, getting this amazing sweet after taste. In fact people go to neighbors who have "meetha pani" (sweet water) for their daily consumption. Not sure if that was D2O and not H2O.
I think from ground water trace elements like lead are more likely. In my experience when I've been in places where groundwater was the household source via electronic pump, it's always been a case where you weren't supposed to drink it. And either had a reverse osmosis machine near by to use to fill bottles, or you just relied on store bought bottled water for drinking and cooking.
It would be interesting if in your cases it was high deuterium water though. It's not something I ever considered really.
Of course when straight groundwater is your best or only option, that's a hell of a lot better than having no source of plausibly safe water available. I've drank lake water where we would just disinfect it with a few drops of bleach for a couple of weeks when on trips. But was always told that this is a short term solution for convenience.
My understanding of the issue with pumped well water (at least where I am) is more that you don't know how long the water has been sitting in pipes or tanks. (Open wells - with a bucket - have different issues as they are open)
The wells here are typically 50m+ meters deep, so if you have a 1 inch connection that's more than 25 litres just sitting in the pipe. For longevity you don't want to run the pump every time you turn on the tap, so there's usually a pressurised tank with another 25L or so and a pressure controlled switch in the pump.
So if you want to get 'fresh' water you first need to run 50L through the system. There's also the issue of extra minerals - the water here has a lot of iron, which turns everything red unless you have a good filter. The filters will have a low flow rate, so you need another tank to store the filtered water. Much easier to just get a RO system or bottled water for drinking :-)
50m of earth is going to produce some of the cleanest water you've ever had, unless of course there is pollution from heavy industry nearby. I know a few people who collect water daily from springs and drink that as is. If you lookup DIY water purification systems they typically have one plastic tank filled with sand and another with charcoal which filters pretty much all of the stuff out you don't want to drink.
>Experiments with mice, rats, and dogs[42] have shown that a degree of 25% deuteration causes (sometimes irreversible) sterility, because neither gametes nor zygotes can develop. High concentrations of heavy water (90%) rapidly kill fish, tadpoles, flatworms, and Drosophila. The only known exception is the anhydrobiotic nematode Panagrolaimus superbus, which is able to survive and reproduce in 99.9% D2O.[40] Mammals (for example, rats) given heavy water to drink die after a week, at a time when their body water approaches about 50% deuteration.[43] The mode of death appears to be the same as that in cytotoxic poisoning (such as chemotherapy) or in acute radiation syndrome (though deuterium is not radioactive)
They used lead vessels to make wine taste sweeter as well. Saying that makes me curious as to what it would actually taste like. Stevia extract and aspartame are sweet but don't taste the same and both different from suger, what is lead like? The second thing that makes me wonder is, do I already know since I live in a city with some lead contamination in the tap water.
Didn't the Romans actually end up making red wine vinegar in the lead pots (letting the wine go bad), and the acetic acid reacted with the lead to form lead acetate (a.k.a. "sugar of lead")?
That would be a very difficult experiment to design. Whatever process one used to isolate heavy water would invariably affect the concentration of trace amounts of other molecules. While the two samples might taste subtly different, the difference might be due to some mineral picked up (or lost) in the separation process. I wonder how rigorously they controlled for this? Would you run a spectroscopic analysis on both samples to ensure they were identical but for the DO2? And, even then, one would have to wonder whether the density of the liquid may be having some subtle effect on the manner in which contaminants—-even if identical in concentration in both samples—-are being uptook into the taste nerves.
They did very careful distillation of the water (and confirmed it with mass spectroscopy). Check out thunderf00t's video which is linked elsewhere in this thread, it's one of the first things he thought to test (and basically his main contribution to the final results: he spent a month doing pretty painstaking distillation, even after it was already demonstrated not to matter).
Wouldn't that be potentially dangerous to drink, given that lots of these deuterium atoms now become part of your body and have slightly different chemical characteristics than hydrogen atoms?
It is talked about in Thunderf00t's video. You essentially need to drink only heavy water for a week for it to be a problem. It is one of the least effective and most expensive way of poisoning yourself.
But the most interesting part is when they tested it on mice. Mice are small and it doesn't take that much for heavy water to start having an effect. And what they noticed is that after some time, mice shunned the heavy water in favor of regular (light) water. Suggesting that mice are able to taste and recognize heavy water as harmful.
By the way, that video is excellent. Thunderf00t is a troll, but when he stops ranting and starts doing science, he makes really great content.
He has some strident opinions on things outside his field (for example he's got a big problem with Christianity) but does that actually make him a troll?
It depends on how you define a troll, in the original sense, no, but he definitely feeds on controversy.
It is not his opinions, and in fact, I mostly tend to agree with these. It is more about if he disagrees with someone, he is going to lose all objectivity and attack him like a rabid dog, backed by all his fans. It is surprising considering that he looks like a competent scientist and promotes rationality.
For example, it looks like he has a grudge against Elon Musk for some reason. No problem with that, I am a bit of a hater myself. However, some (not all) of his argument are simply wrong, or at least incomplete, and he repeats them over and over, mixed with movie clips meant to ridicule, and he never backs down.
Even when it supports my ideas and I enjoy two minutes of hate as much as anyone, I think it is toxic. The only purpose I see to these videos is to reinforce ideas people already have and turn them into zealots instead of educating others. Not so different from the cults he denounces.
There's a lot of cringey comments and statements in that video that are just hilariously wrong I thought it might be satire at first. Apparently you can't put steel in contact with concrete because a tiny whiff of surface corrosion is going to seriously risk the integrity of that 3/4" thick steel pipe... Not to mention claiming that clearly they didn't account for linear expansion of the pipe right after poking at the linear bearing material and saying it looks like they put it on some type of plywood.
That video is 20 minutes of him spouting off the same kind of nonsense and trivial mistakes that he spends every other video deriding other people for making. He even makes some mistakes that are basically just pure physics, which he of all people should know is suspicious on the face of it. He claimed that if a test vehicle failed to slow down and impacted the far end that it would rupture the test track. It's a 3/4" steel pipe with a massive thick door and the inside being at a weak vacuum, it's not coming off. Not to mention his differential heating claims which would not change with length given that the test track can obviously resist the bending with just the weight of the tube elastically deforming it to keep it straight.
His own zealotry on some subjects blinds him to his own obvious mistakes. If it was someone else making a video with so many errors he would be all over debunking it.
Yes, I have a similar opinion. It one thing if he’s tearing down yet another scam Kickstarter that’s just the same dehumidifier you can buy at any store, but when he’s wrong about something it’s a problem.
I also find those videos very grating and tiresome. That’s not entirely his fault though, some of the videos he excerpts from are themselves dreadful. Leaving that part aside, the mocking tone he adopts just isn’t necessary.
On the other hand, when he’s presenting an actual technical topic his videos are great.
Yeah, this is the problem. He's also all too willing to engage in stupid slap-fights with flat earthers, who are very happy to antagonise him for more publicity.
The way he over-promises, his PR stunts, and worst of all, his cult-like following. I also think that Hyperloop is a borderline scam.
And it is a shame because SpaceX is awesome and I credit Tesla for making electric cars people actually want to drive, and PayPal served me well in the early days.
> on things outside his field (for example he's got a big problem with Christianity)
For a hard scientist, that's almost a given. He'd be a lousy hard scientist if he didn't have a big problem with it (both when it comes to internal contradictions and in the mismatch with the real world).
"Because of that altered bonding behavior – which can affect bodily chemistry if you ingest deuterium in D2O – scientists generally say it's not a great idea to drink heavy water, at least not in high doses."
But also note your body already has to be robust against it to some degree, because water will normally have a certain amount of heavy water in it naturally, so it's not like it's a deadly deadly toxin. It's just something you shouldn't drink a lot of.
My point is simply that this isn't like botulism toxin or something, but something that will require a much larger dose. I'm targeting a correct mental model. It's dangerous, but not that dangerous.
"But, you have to continuously drink and eat only heavy water for several days to see an effect. Replacing 20% of regular water in cells with heavy water is survivable for humans and other mammals (although not recommended). Swapping 25% of water with heavy water causes (sometimes irreversible) sterilization. Replacing 50% of water with heavy water is lethal. It’s not a pretty death, either. Heavy water poisoning resembles radiation poisoning or cytotoxic poisoning from chemotherapy."
It looks like from the paper's methods [0] that they did "sip and spit," maybe similar to wine tasting? Plus rinsing with normal water in between tastes. I think that, plus D2O not being particularly poisonous in low quantities, would make that a safe enough experiment.
In the same paragraph they say "All research procedures were ethically approved by the Committee for the Use of Human Subjects in Research" at their university, so they probably had to provide a lot of evidence that it was safe beforehand.
https://www.youtube.com/watch?v=VLiirA5ooS0 shows that deuterium ice sinks, but the density is only a bit more than water, so it doesn’t sink “properly”. Although perhaps they didn’t get pure deuterium, since heavy water is about 11% denser than regular water.
For better sinking ice, mix deuterium and oxygen-18.
For the best sinking ice use super heavy water[1] (substitute tritium instead of deuterium) although it is toxic: “The median lethal dose (LD50) of tritium assimilated by the body is estimated to be 370 GBq (10 Ci). Higher doses can be tolerated with forced fluid intake to reduce the biological half life.”
> For better sinking ice, mix deuterium and oxygen-18.
One of the videos linked by other comments mentioned that they spend $1000 on a tiny amount of O18 to see if it would also taste sweet. Ice cubes made from that seem to be the kind of party trick best reserved for celebrating your first billion.
I could see the physics department doing this, if it wasn't that expensive. They used to have cocktails with dry ice in them - not sure how legal that is, but it's great fun. If you breathe in the vapour you can taste the drink quite strongly already.
(Note, if you put too much dry ice the water in your drink will freeze and that can affect the taste quite negatively..)
It is, but only a long period of time. A glass of deuterated water won't do anything to you, but if you drank it for weeks on end you'd have some serious problems
You would need to drink enough of it for it to form a significant fraction of your body's water which would take days with fasting and weeks otherwise. And 10's of 1000's of $.
It would be interesting to see whether the sweet taste is because of pure coincidence or whether it is because a small quantity of heavy water confers an evolutionary advantage.
Evolution doesn’t need mutations that give perfection just an advantage on average. How much does lead paint occur in the environment humans traditionally evolved in?
Heavy water exists naturally. It is reasonably common, and since it has a different density there might well be natural or biological processes which might concentrate it...
I'd be curious at what concentration people can detect heavy water. My guess is that this concentration does not occur naturally, but I could be wrong.
I'm betting the latter. Consider that lead also tastes sweet[1], that's why kids would eat lead paint. Our ancestors were never placed in situations where eating either lead or heavy water could change evolutionary outcomes because these substances are not easily obtained in high concentrations in nature.
That's really amazing that human taste buds are such sensitive chemical detectors. We still can't build anything as good at anything near that size.
Off-topic: Is anyone else reminded of that episode of Hogan's Heroes where the Germans store heavy water in the POW camp to protect it from allied bombers, and Hogan tricks Colonol Klink into drinking the heavy water by telling him it had some kind of health benefit? https://www.pinterest.ca/pin/584201382887878852/
There's a remarkable spectrum of subtle differences in the way water tastes. Plastic bottles, metal pipes, using a straw, city tap water, spring water, well water, chlorine, filters, they all add a little flavor.
Well water is fantastic. I can notice the difference city to city and have since switched to certain types of bottled water. Making ice cubes with bottled water makes drinks taste differently.
If you want to avoid the cost and trash of bottled water, try keeping a pitcher of water(or reusable water bottles filled from the tap) in your fridge. The chlorine is pretty volatile, and will evaporate off within a day(assuming the pitcher isn't air tight). Just have some rotating stock so you can always have water ready to drink or make ice cubes. Of course you could also go the filtration route, but that adds the upfront cost of the system, and continuous cost of filters and wasted water.
It depends on the treatment method your city uses. Chlorine gas will evaporate out, but chloramine won't, and will also react with a lot of things downstream to make nasty tasting organics, for example if you use the water in brewing.
And can depend on where in a city you are. And sometimes the different treatment systems are still mained to eachother so shifting demand and supply can change which water you’re drinking from.
Huh, I always heard this as "a few hours" and assumed it was about getting the right temperature.
(And from my darkroom days, I'm fairly good at nailing 20 °C with my fingers, so I just waited for the tap to give me the right temperature and then poured it straight into the pots.)
As someone who grew up with well water, it tasted fine, but (at least for me based on local conditions), it was a huge pain in the ass.
Low pressure, extremely hard to the point where soap is useless and we had to replace things regularly from scale build up, the UV filter thing we had to run in the basement, the worry that one day you could randomly lose the prime on the pump and they'd have to dig to get it back (which happened once), no fluoride so my teeth aren't the best.
Give me that carbon filtered (removes the chlorine taste) city water any day :)
Local conditions and probably equipment will make a difference in pressure. My well kicks on around 35 psi and off around 65, if I'm remembering right. Of course, it failed in the past year, no digging required, but it did take the better part of a day to pull up the old one, and attach a new one and lower it down. Plus one day of troubleshooting and a day of waiting for the pump to arrive didn't make a fun few days.
I've been living in a place with a softener on a well for a while now. Many people have asked about salty water, but I don't find it to be an issue at all. I even prefer water from our softened tap over the unsoftened one. I don't notice rings or residue in my drinking glasses.
I think a common misconception is that your water runs through the salt. In reality, the water runs through a filter and the salt water is used to periodically flush the accumulated metals out of the filter. This could lead to some residual salt, but it will get flushed away quickly. The other source of salty water is a busted valve. Replace it and the water will be fine again.
Potassium chloride water softening salt is more expensive, but unless you use way more water than we do, I don't find it to be an unreasonable expense.
...the worry that one day you could randomly lose the prime on the pump and they'd have to dig to get it back (which happened once)...
Where was this? Pumps are placed at the bottom of wells and avoid this problem entirely. It's physically impossible for a pump placed at the top to raise water more than 10m.
I'll second a reverse osmosis filter. We filter municipal water through one to get drinking water and, honestly, we're very happy with it. It's not as good as, you know, Swiss mountain water, but it's pretty close.
Do you have a recommendation for a countertop distilling machine? A back of the napkin calculation shows that it would be 50% cheaper for me to pay for the electricity and distill water myself than buy bottled water, but the idea had never occurred to me.
While not as good as distilling can I suggest filtering like the rain fresh system uses. I have used them for decades because well water has too much minerals (bad tasting) in this part of Ontario.
Seattle has fantastic city water. Most months of the year, Oakland water is very good (offer not valid for all combinations of reservoir and pipes, your mileage may vary).
Also, if you got used to something like iron or calcium enrichment, you might just not like those vintages, even if they're "objectively" good.
Oppositely, I've lived in Toronto for quite a long time, but my family all live in rural Ontario. A bunch of years ago my parents finally got over the fear factor and came to the city to visit.
My dad commented specifically that he was impressed at the taste of our tap water, and thought it was an unexpected highlight of the trip.
We grew up on well water. Although by this point they were living "in town" so it is possible that their water has more chlorine, etc, than Toronto's. When I visit them, their tap water tastes dull (but not bad) to me, so there is that.
The tap water where I live in Canada is fantastic. But when I'm served filtered water with tap water ice cubes I can tell the difference pretty easily.
The remarkable thing here is that it's not a chemical detection, but a nuclear one. Chemically, H2O and D2O are identical.
We knew that our taste buds (and smell receptors) are incredibly sensitive to small amounts of chemicals. It's somewhat unexpected that they could distinguish molecular weights.
The standard theory of odor is that it's a lock-and-key process, like the immune system (and related to it). But there are some odd holes in that theory, like why sulfur compounds smell "alike", even though they're different keys fitting different locks (and we can't even exactly say what "alike" means).
This one guy suggests that it acts like a spectroscope, sensing the way atoms vibrate within the molecule. It's a brilliant theory that explains a lot of stuff, except that it's completely insane and there's nothing even vaguely like a biological mechanism that would enable it to work. He tried testing it with molecules that substituted deuterium for hydrogen, which alters the spectroscopic signature -- but got mixed results.
Smell and taste are only distantly related as mechanisms (taste is actually several very different mechanisms, and that's well-documented). This suggests that there's even more to it than that. Does this bring Luca Turin back? Dunno. He seems to have abandoned smell research entirely.
Deuterium is so much heavier than regular hydrogen that the bond lengths in D2O are shortened by enough (~3%) to affect cell chemistry. Also significant differences in boiling points and other physical properties.
I conducted an experiment once to settle an argument about identifying vodka by smell and taste. The argument was since regulations require 95+% neutral spirits to be diluted with water, the smell and taste should be uniform. We used 3 store bought vodkas reportedly made from potato, corn, or grain and our own mixtures of 95% grain alcohol with various water sources to matching dilution. Participants were allowed to sample the solutions and told what they were, then given the solutions blind in a random order and asked to identify each solution. Our participant group was too small and controls too loose to make any significant conclusions, but our guess was that pH was not regulated and could be a discerning factor. One of the participants scoring a near perfect score settled the bet. Even the smokers scored higher than what we expected for purely random guesses.
I'm still having a hard time trying to understand why you where surprised they weren't uniform. You can add .0001% of something to a food and taste the difference depending on what you added.
if someone making a sandwich puts mustard on a sandwich and uses that knife to cut my bread, I can taste the mustard even though they wiped the knife. the % of mustard on my sandwich has to be very, very small.
That’s not a very good analogy. It’s more like the concentration of nitrogen in the atmosphere increasing 5% and you being able to smell it. Ethanol is a notoriously overwhelming flavor and the rest of vodka is intended to be flavorless.
Hey, whatever you've been drinking hasn't killed you yet.
Really, up until a few generations ago, people tended to stay put and a family might drink from the same set of water sources for centuries. The only reason water would ever taste different is if something bad had happened to it.
I remember sitting in an APS talk 7 or so years back where the room more or less laughed at a researcher presenting hypotheses on how deuterium detection might be possible in fruitfly proteins.
I hated that entire room and what it stood for. Philistines masquerading as professors. No scientific talk which was done systematically should be laughed at like that.
I'd be very skeptical that there is an actual biological mechanism that detects deuterium intentionally, there simply isn't really any need to this given that D2O is very rare. I'm not saying they don't exist, but there is no compelling argument why they would evolve. I'm not saying this can't exist, but I'd need some pretty convincing evidence that there's an actual biological reason for such a mechanism.
But of course detection would be possible, it has been known for many decades that different isotopes change reaction kinetics (https://en.wikipedia.org/wiki/Kinetic_isotope_effect). That is a measurable chemical effect, so of course a protein could make use of it. This is something I was taught in university, so this is not any kind of obscure knowledge, but mainstream chemistry.
Agreed, the suppression of research in this area, for decades, reveals a fundamental failure in how we as a society conduct science.
E.g., now that it turns out that saturated fat is wholly harmless, the past five decades spent failing to investigate why meat consumption really causes circulatory disease is practically criminal. How many early deaths are traceable to this sustained failure? How many, to having continued permitting trans fats in stuff sold as if it were food? How many to oxidized unsaturated fats?
People like to insist that science always gets it right in the end, but these corrections are always isolated flukes. The pattern suggests a clear majority never get corrected.
mRNA vaccines are just such a fluke; their inventor spent her whole career being spit on. How many died, for lack of mRNA vaccines in past decades when the method could have accelerated vaccine development by years back then, instead of only now?
A great fount of suppressed truths must lie dreaming in the work of women and minorities driven from their fields.
There's still some situations where saturated fats might be bad (iirc high fat+high carb at the same time is worse than just high carb) but there really seems to be no reason at all to believe that low-sodium foods are healthier. The problem with fries is everything except for the salt.
As an student, ta and undergraduate instructor the one thing that offended me outright was people being discouraged from engaging. 99% of instruction is communication, largely one direction and engagement is the only data to evaluate the effectiveness.
To me it reinforces the one correct reason to become a professor: you want to raise the standard of professionals / colleagues in the field by mass education. Your goal is to increase quality across the board, and the only way to be successful is to be a good and engaging communicator. There are networked benefits from creating success for your students.
So is this ability surprising though? As water is essential for surival, the ability to taste when water is 'off' would be a powerful evolutionary tool. This is maybe why water tastes 'like nothing' so we can better tell when there is something wrong with it.
It is pretty suprising!. There's no strong evolutionary reason for being able to taste the difference: there's no natural source of such concentrated D20 and it's only toxic if you ingest a lot of the concentrated stuff. It's not something any animal is going to encounter in nature.
And by conventional chemical wisdom D20 and H20 are virtually identical: the electron structure is the same and that basically dictates the chemistry. The only significant difference is the mass of the molecule (about 10% heavier), and experiments with oxygen-18 water (which has the same mass as D20) showed it doesn't taste of anything, so it must be due to very slight changes in structure between the two.
Provided you gain appropriate consent, there are definitely ways in which you can discover exactly how much the taste of these fluids vary from person to person.
Please do not give me heavy water without asking. I might not have been compiled with CONFIG_D20 support. I can tell you, but with small children, you have to check.
A side effect of improving the taste of tap water would be less soft drink consumption. I hate the taste of chlorine in the water. Its probably bad for you if you bath and shower in it too. Britta Filters for the tap water, and charcoal filter for the shower head are two very inexpensive ways to improve your quality of life. Highly recommend both. And probably some sort of glass bottle for on the go water consumption. I can taste the plastic in water bottles, especially on a hot summer day while it was left in the car.
The TLDR is that also chemistry is mostly about electric charges, actually speed plays a role in which reaction is favored when there are competing reactions, and reaction rate decreases with mass. Hydrogen being very small, one neutron makes a big mass difference, so it's the most susceptible to mass change.
Taste buds have helped us evolve as humans. In the beginning, the sense of taste helped us test the foods we ate: bitter and sour tastes might indicate poisonous plants or rotting foods. The back of our tongue is sensitive to bitter tastes so we can spit out poisonous or spoiled foods before we swallow them. Sweet and salty tastes let us know foods were rich in nutrients.
>There is never an ‘advantage’ to limiting ones foods.
I agree in theory, if there were no tradeoffs required to consume any particular thing. But my comment took for granted that there are. Even for really versatile species, there are to some extent.
Yup. My parents live up near San Francisco. Their water comes out of the tap totally clear, tastes "fresh".
I've lived in multiple San Jose homes now, including SJSU dorms, and in every one of those, the water came out of the tap cloudy and if you let any dishes/silverware air dry after washing, they have a significant amount of white precipitate on them that becomes impossible to clean off without some kind of mild acid, like vinegar. At my parents house you can get water spots on things but they're typically quite light and easy to clean off.
In addition to that, the flavor just tastes very wrong in San Jose. I lived in SJ for 9 years and never got used to it, either.
There are some sites that have PPM ratings for different cities in California and it seems like San Jose consistently rates as one of the highest.
> In tests with mice, however, the animals did not seem to prefer drinking heavy water over regular water, although they did show a preference for sugared water – suggesting that in mice, D2O does not elicit the same sweet taste that people can perceive.
I was reminded that rodents also can’t taste aspartame[1], and that in general human taste buds are more finely-tuned than many other mammals (we can detect isomers and many complex bitter chemicals, whereas many other animals can only do the amino acids, sodium, and simple carbohydrates).
Having never drank it myself I was wondering if the sweet taste of heavy water is distinctly “artificial” in the way that sucralose/aspartame/etc in water is immediately distinguishable from regular sugar.
[1] https://www.nature.com/articles/nature726