Discrimination experiment no. 2

Interesting dinner party with a group of friends. I brought this cru bourgeois Bordeaux, half of which had been decanted 3 hours earlier. We followed the protocol described in the previous discrimination experiment. I described the difference we were looking for in terms of primary versus secondary and tertiary aromas. Of the 7 participants, only one correctly identified the source of the wines. (It was not me.) Now, people’s reasons for their choices did not always follow the description I had given at the beginning; many described one wine as having more complex aromas than the other (that was identified in these cases as the wine from the bottle); some made reference to the acidity. So, maybe there was a flaw in the instructions. Me, I found it very hard to distinguish between the two. None of the people in the group was a self-professed conoisseur.

So, good addition to the data set. I think we need a larger N size.

Discrimination experiment no. 1

This is a new series of experiments following the protocol outlined in my last post. It involves just two glasses, and the test to see if the presence of secondary and tertiary aromas discriminates between the bottle and decanter. For the first experiment in this series I used an inexpensive Bordeaux. Here are my notes, written before the reveal:

On the left, fine spicy cedar notes and good fruit. On the right, a slightly funky mushroom overtone. So the one on the right is the bottle.

I was right. And tasting after the reveal, I thought the tannins on the decanted palate were mollified by the soft fruit. Perhaps this is behind the notes you sometimes read saying that the tannins softened with air. I’ve never believed it possible that the tannin composition changes chemically over such a short time, but possibly the revealed fruit aromas create a perception of softening.

I found the difference quite decisive. In previous breathing experiments the difference often seemed very subtle. Maybe formulating a hypothesis sharpens the mind’s attention in a way not present when you are simply trying to decide if there is any difference at all.

Here is my tasting note on the wine.

Analysis of breathing experiment statistics

After 10 breathing experiments I decided to run some numbers on the results. The raw data is here. I don’t know how a statistician would handle inferences from this data, but I can calculate probabilities for a binomial distribution. The fundamental question was whether there was a detectable difference between wine that had been allowed to sit in a decanter for a few hours (typically 3–6) and wine from the same bottle that had sat under cork and argon gas (or from a different bottle of the same wine in earlier experiments). Subjects were presented with three glasses and had to pick the one that was not like the others, following this protocol. Here are the statistics for the whole group, and for me alone. The last column is the probability of doing as well or better by chance alone (assuming a 1/3 chance of a correct guess in each trial).

Group No. of trials No. correct
Probability 
Everyone 30 16 0.02
Me 10 7 0.02

I am sufficiently convinced by this that there is a difference detectable by humans. But feel free to check the data and disagree in the comments.

I also ran the conditional probabilities on correctly identifying the source of the wine given that you had correctly picked the odd one out.

Group No. of trials No. correct Probability
Everyone 16 10 0.22
Me 7 5 0.23

This is less convincing, although of course the sample size is smaller. But it suggests to me the next series of experiments. Having established that decanting makes a small but detectable difference, the next question is: what is the difference? Reading over my notes, I think it is reasonable to make a hypothesis in terms of primary, secondary, and tertiary aromas. There’s a nice description these at Wine Folly. Primary aromas are the aromas coming from the grape itself (fruit, flowers, herbs). Secondary aromas come from the fermentation process (yeast, cream, lees, mushroom, and Brettanomyces aromas such as barnyard, game, and bacon) and tertiary aromas come from the aging process, particularly from aging in oak barrels (vanilla, nuts, baking spices, cedar, smoke, tobacco, leaves). We will adopt the terminology from Wine Folly: “aroma” means the primary aromas, and “bouquet” means the secondary and tertiary aromas.

The hypothesis we will work with in this series of experiments is:

Wine from a freshly opened bottle has a stronger bouquet, which tends to mask the aroma. The aroma is more prominent in wine from the decanter.

I’ll use a new experimental protocol. The question is no longer whether there is a difference, but whether a particular description of the difference is accurate and usable by humans. I’ll present subjects with two glasses blind, one from the bottle and one from the decanter, ask them to read the description of aromas above, and then ask them to apply the hypothesis to identify which is which.

I will also collect data on preference, and for that reason I will organize the experiments by varietal, starting with Bordeaux varietals and blends. Then I will move onto pinot noir. The conventional wisdom is that breathing is good for the former and not for the latter. The breathing experiments so far somewhat support this.

Breathing experiment no. 10

This time I chose the 2014 Matthiasson Napa Valley Cabernet Sauvignon. Matthiasson makes wonderful wines that blend the vividness of California with the structure and balance of France. (Jason, photo of label below.) But I digress. Usual protocol. My notes:

First impression: first one is more floral and fruitier, second two more masked with a cedary spicy note, so dbb. No discernible difference on the palate. In this case the masking note is quite nice. At one point I almost wanted to reverse the classification of the first and third bottles, for bbd. But I started to get confused, so went with my first impression, even though it has failed me the last couple of times.

Failed me again: the correct configuration was my second guess, bbd. I seem to be having trouble second guessing whether I should second guess. Still, either way, the thing I thought I was detecting—the presence or absence of a masking note—is consistent with previous breathing experiments with cabernet and Bordeaux blends. So I think there’s something in that hypothesis, and maybe I should try to design an experiment to test it explicitly. Perhaps a very long decant to emphasize the difference.

John Gilman’s often talks about a top note of bla bla bla. I think I’m beginning to understand that, and used the phrase in my tasting note for this wine.

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