Posts Tagged wine
Applying multifactor testing to a wine-making simulator
The Pudding, a digital publication devoted to data-driven visualization of current culture, currently features a very interesting essay on Wine and Math, A Model Pairing. The author, Lars Verspohl, provides many eye-catching graphics of the analytics behind producing quality wines.
What got my attention was a simulator for making red Portuguese Vinho Verde. Verspohl sifted through a dataset of 1600 wines to develop a model that predicts quality based on 11 factors. You can slide these up and down to try making a fine wine—rated at 7 or more on a scale of 10.
Not being content with haphazard searching on so many variables, I set up a multifactor test. Using version 13 of Design-Expert® software (free trial here), I laid out a minimum-run (plus 2) screening design on the 8 factors ranked most important by Verspohl’s Random Forest analysis, bypassing the bottom 3 (pH, residual sugar and free sulfur dioxide). I then worked through the 18 combinations and recorded the quality results in percent.
As shown on its Pareto plot of effects, Design-Expert revealed that only 5 of the effects tested produced significant effects.
The numeric optimization tools led to the optimal red Vinho Verde flagged in this 3D plot at the highest alcohol and lowest volatile acid levels. Settings for the other attributes are indicated by the position of the slide bars, e.g.; sulphates at the high level*. The factors defaulted to the middle are ones that did not get picked for the model.
Now that I’ve solved this simulator, my next mission is to locate a bottle of red Vinho Verde for some one-glass-at-a-time testing.
*This result surprised me—not being a big fan of sulfurous compounds in wines. This skepticism is borne out by another take on the Vinho Verde wine here. The only way to resolve the conflicting results would be to do an actual experiment on the composition of a red wine, ideally a mixture design for optimal formulation.
Testing the adage that if you drink beer before wine then you will feel fine
Just in time for the partying hearty for Christmas today, my son-in-law Ryan, a chemist with 3M, alerted me to a statistical study published after last year’s holiday season by the The American Journal of Clinical Nutrition that questioned the advice of grape or grain but never the twain. Naturally, being a drinker of these undistilled alcoholic beverages, I wondered if my tendency to drink beer before dinner and wine for the meal would pass the test. But being a wonk for design of experiments, I was most curious to see a randomized controlled multiarm matched-triplet crossover trial—pictured below for this experiment on the order of addition for beer and/or wine.
Based on results from 90 participants, including a control group, “neither type nor order of consumed alcoholic beverages significantly affected hangover intensity (P > 0.05)”. What really mattered was the total consumption, although, interestingly, hangover intensity did not correlate to breath alcohol concentration (BrAC). However, the authors warn that
“The fact that we did not find a direct correlation between maximal BrAC and hangover intensity should not be misinterpreted as an invitation to drink until the cows come home. Likely, this correlation overall does exist but is not directly apparent in the narrow range of peak alcohol levels studied here.”
It’s disclosed at the end that Carlsberg provided the beer (premium Pilsner lager recipe from 1847) free of charge “for the sole purpose of utilization in this study”. Although I trust the author’s disclaimer of any bias, perhaps further study is warranted with stronger beers such as a Belgian trippel. Maybe wine would then be best drunk first. To be continued…
Correlation of price of wine with the fineness of its taste–an absurd example
Posted by mark in Consumer behavior on December 22, 2012
Behavioral Economics Professor Dan Ariely of Duke University provides an illuminating and humorous example of irrational valuation in his advice column today for Wall Street Journal. It seems that this Christmas holiday weekend may be ruined for a couple who took advantage of a buy-one-get-one-free (BOGO) sale on a fine wine. Actually they paid $17 for one bottle and a nickel ($0.05) for the other. They asked Professor Ariely to help them escape a terrible dilemma: For the holiday party would it be OK to bring the cheap wine? Ha ha!
I hope that for the coming year all of you readers of StatsMadeEasy do not get hung up spurious issues like this relating to correlation and causation or any other statistical kerfuffles. Happy Holidays and New Year!
PS. I leave you with this toast to 2013–a picture taken last week during my tour of a winery in the Colchagua Valley south of Santiago, Chile. Cheers!