Medical researchers have different definitions, but in the jargon of wine tasters if you taste a wine blind you know its broad class, e.g. region or grape variety, but the other details are withheld, and double-blind means that in principle you know nothing about the wine. Then there is blind tasting where you are actively mislead about what you are tasting.
The most common use of this may be in those experiments that lead to the newspaper headlines about how wine snobs have been fooled. For example, the one where red dye was added to white wine, leading tasters to describe it in terms of red wine aromas (Morrot, Brochet and Dubourdieu, 2001, The color of odors, Brain Lang, 79 , 309-320). I was caught by one of these underhand tricks at a recent tasting.
As part of something billed as a “Comparative Tasting of Red Burgundy and Pinot Noir from around the World” three wines were presented blind. One of them was awful. It was pale mahogany, and horribly oxidised beyond recognition. I guessed it was a cheap New World Pinot Noir, mainly I didn’t think out host would let any decent wine deteriorate so badly. So in the ensuing game of “options” I was out at the first hurdle, because it was Old World. When the question “Is it from Spain?” came up the penny began to drop, but I was out of the running at that stage. The wine was actually Urbina Rioja Gran Riserva Especial 1994. Along with many others, I was well and truly, er, well let’s just say wrong.
Nothing too unusual with that – anyone that has tried even above-board single-blind tastings will be used to messing up. The remarkable thing though, was that when I returned to taste the wine it had totally transformed – form a horribly oxidised Pinot Noir to a Rioja that was perfectly drinkable. To be honest it was probably not the freshest of samples considering its vintage, but certainly not the disgusting liquid I tasted earlier. The transformative effect of the information on the label was, to me at least, as powerful as various optical illusions I have seen, e.g. the one where you initially see two faces or a vase until someone tells you there is another interpretation.
Thanks to John Smithson for releasing this image into the public domain – it is also used in the Wikipedia article on the Rubin Vase. I am not sure if the wine was bi-stable like the image, because my sample ran out too quickly