Chemistry - Does heavy water taste sweet?
Solution 1:
According to H.C. Urey and G. Failla, Science 15 Mar 1935, Vol. 81, Issue 2098, pp. 273, there's no difference in the taste of ordinary and heavy water.
Solution 2:
OK, first of all I want to say I really dislike the videos that this guy puts out, since he is promoting unsafe handling of chemicals. He might know what he's doing, but it's a terrible example.
To the actual question: surprisingly there are nearly no sources on this. I can understand that this isn't something a lot of people would try nowadays, but I imagined that a lot of people tried 50 years ago or something like that.
There's one science article describing a blind taste test of three persons in comparison to distilled water, and they couldn't spot a difference.
Another paper describes a difference, and also cites older research that showed that rats avoid $\ce{D2O}$ if they have the option to choose. But that might also be smell. It is known that deuterated substances can have a different smell and taste.
Heavy water also has a higher density and viscosity, so that might also be a factor which makes it "taste" different. Fun fact: it also has a different color.
And well, he didn't do the testing in a scientific manner, which would minimally include blinding the observer.
Solution 3:
From the abstract of the article by Abu et al. [1]:
Here we conclusively demonstrate that humans are, nevertheless, able to distinguish $\ce{D2O}$ from $\ce{H2O}$ by taste. Indeed, highly purified heavy water has a distinctly sweeter taste than same-purity normal water and adds to perceived sweetness of sweeteners. In contrast, mice do not prefer $\ce{D2O}$ over $\ce{H2O},$ indicating that they are not likely to perceive heavy water as sweet. For humans, the sweet taste of $\ce{D2O}$ is suppressed by lactisole, which is a known sweetness inhibitor acting via the TAS1R3 monomer of the TAS1R2/TAS1R3 sweet taste receptor. HEK 293T cells transfected with the TAS1R2/TAS1R3 heterodimer and the chimeric Gα16gust44 G-protein are activated by $\ce{D2O}$ but not by $\ce{H2O}$. The present study resolves a long-standing controversy about the taste of heavy water, confirms that its sweet taste is mediated by the human TAS1R2/TAS1R3 taste receptor, and opens way to future studies of potential sites and modes of action.
Reference
- Abu, N. B.; Mason, P. E.; Klein, H.; Dubovski, N.; Shoshan-Galeczki, Y. B.; Malach, E.; Pražienková, V.; Maletínská, L.; Tempra, C.; Chamorro, V. C.; Cvačka, J.; Behrens, M.; Niv, M. Y.; Jungwirth, P. Sweet Taste of Heavy Water. bioRxiv 2020, 2020.05.22.110205. DOI: 10.1101/2020.05.22.110205
Solution 4:
I tastet heavy water assuming it has not taste and was surprised about the sweet taste (Aldrich, Deuterium oxide, 99.9%). The bottle was old but still sealed. Three more people also defined the content of the same bottle as slightly sweet without knowing what my perception was.