The Legendary Study That Embarrassed Wine Experts (2014)

1. They tested whether the dye was tasteless on students who were not wine students, just students pulled off of the agricultural school campus. This study basically says "Group A, who aren't trained in tasting, say that there's no taste. However, Group B, trained in tasting, report a difference." (More on that "difference" below.)

2. They tested the dye as being tasteless when mixed with wine. If it's truly tasteless they should do the same test with water. I suspect they don't because it does have a taste, more in this below.

3. Even in their experiment on untrained students trying to show that it is "tasteless," the wine containing dye was in fact identified as tasting different 120/300 times (expected value 100/300 if there was no difference in taste). This is not enough evidence to show definitively whether the dye is tasteless or not. The raw evidence reported actually indicates that it is more likely to have a taste than to not have a taste.

4. The way that they asked the wine students to compare the wines is convoluted - overly complicated, as if to obscure the truth. The wine students were asked to compare wines by sorting each feature as belonging more to Wine A versus Wine B. So, if neither wine particularly has some feature, you would still be forced to assign the feature to one of the two wines. The only two wine comparisons done were true white wine versus true red wine, and then true white wine versus white wine dyed to look red. They never actually do a comparison of the white wine dyed to look red compared to true red wine, which would be the most informative comparison.

I will transition here from methodological issues with this study to my opinion on this study.

This study appears to have been designed with a specific outcome in mind, regardless of the underlying truth about people's ability to taste wine. The conclusions stated in the study are not supported by the evidence actually collected in the study. The best thing I can say for this paper is that they report their methods clearly enough for someone to be able to see that they are heavily flawed.

The training part is very much about learning to identify specific chemicals, or groups of chemicals. That absolutely is raw detection, as you say. Let me provide some examples. For the "level 1" training, the most basic stuff, samples would be things like: plain water, acid (very dilute sulphuric acid), alkali (very dilute sodium hydroxide), metal (copper and nickel metal coins in a bottle of water), rubber (rubber tubing cut up in a bottle of water), salt, sugar and a few others I've forgotten (this was 22 years ago), maybe some other major categories like aldehydes. Just for the record, you don't actually drink any of that stuff down, it's tasting only and its very dilute! When the solutions are all clear, being able to identify each blind from some anonymised samples is surprisingly difficult, especially when diluted so it's more subtle. But it's absolutely possible with practice.

The higher levels are all more subtle things like many different flavour compounds. For wine and beer, almost exclusively aromatic hydrocarbons, along with esters and other flavour compounds. I never did this but it's the same process, but it's much more difficult. Instead of under 10, you have an industry-standard reference set of IIRC around 60 compounds, and you have to be able to identify each and every one blind when diluted in isolation. And obviously in a drink you have to be able to identify them all individually in combination as well. This is the part that takes the most time and effort to master. And it's these people that I wouldn't question too much regarding their skills, because they actually had to pass objective assessments to demonstrate those skills. This is really hard!

This is why I'm a little disappointed that the original article mentioned using students. They would be unlikely to have achieved that level of competence. It takes many months, if not years, of regular practice to get to that level. I spent a year doing the basic training and then continual daily testing and monthly assessments, and while I still class myself as being at a very basic level, I'd still likely have more practical experience than them.

Regarding subjectivity and the "experience" of taste, that's absolutely taken on board as well. But it's a separate question. For where I worked, every product had a spec sheet, mostly physical and chemical properties but also a taste profile. The professional tasters could make sure it met that profile exactly. The rest of us just made sure it looked and tasted as a consumer would expect it to.

For those who are wondering about why those specific "level 1" tastes, they aren't random and they are actually serving an additional purpose. Those are to also pick up on product contamination. Metal and rubber from storage tanks and pipework. Acid and alkali from cleaning agents and coolant. I actually had to check for the latter once when we had a potential set of hairline cracks in a tank suspected of leaching coolant [in beverage production, they use very concentrated KCl since it's non-toxic if it leaks, but at pH14 it's nasty stuff].

There is an incredibly broad array of flavor, mouth feel, aromas, etc., in both red and white wine and while you and I might very reliably discern a Napa Chardonnay from an Argentine Malbec there are many white and red wines that are well off the spectrum of what we think of as "red" and "white" wines.

I have done a lot of wine tasting all over the world and I am certain you could fool me with regard to red vs. white - if you chose interesting and unconventional examples ...

The problem is that white/red is a very large grouping of wine. There are very light reds with low tannins that could be hard to tell particularly if served at room temp. There are some robust white wines that fall into this same overlap. In general, red vs. white is normally pretty easy assuming typical red and white wine.

Within these large groupings of white/red there are also other trick wines. Reds where the grape seems like a different grape due the region or wine process. Dry Rieslings are often tricky because most people assume sweet. So non-expert tasters being tricked by trick wines is not really an interesting find.

The problem for most people with wine tasting is it's hard to do it in a way to learn. It's not enough to buy a bottle once/week. In one trip to France, I tasted 100+ wines over a 2 week period. Only when you have wines side by side, day after day do you really start to learn. Sommeliers taste 1000s of wines over many years, taking notes and actively working to learn the flavors.