Wine PhD

It appears that the average wind speed in Davis over 20 years is quite stable. There is some variation across years, but each month has a characteristic profile. Right now is September and we can expect afternoon winds that start to taper off at about 5pm. November-January have windy nights, where the overnight wind speed stays higher compared to July-September. I took 20 years worth of hourly weather data from CIMIS (~175k observations) and distilled it down to this plot. Here averages are taken by month, year, and hour. The year and hour makes sense, but month is a bit arbitrary. Why should Aug 31 and Sept 1 be grouped in different months? Sept 1 is more similar to Aug 31 than it is to Sept 28th. Despite the arbitrary nature of month breaks, it is still quite interesting to see how stable the patterns are year to year, hour to hour.

Code

#historic Davis wind speed
#with CIMIS
#Greg Hirson, 2010

library(cimis)
library(lattice)
library(reshape)
library(ggplot2)

#years = 1990:2009
d = mcimisannual("006", 1990:2009, period = "hourly")
closeAllConnections()

#yearly average wind speed by hour and month
d1 = ddply(d, ~ time + months(datetime) + year,
	.fun = function(df)mean(df$wind_speed, na.rm=T))
d1$time = d1$time/100
d1$months.datetime. = factor(d1$months.datetime.,
	levels = unique(months(d$datetime)))

g1 = ggplot(d1, aes(x = time, y = V1, colour = factor(year)))

g1 + geom_line() + facet_wrap(~months.datetime.) +
     scale_x_continuous("Hour") +
     scale_y_continuous("Wind Speed (mph)") + labs(colour = "Year")

Over a two week period the students (and staff) in the Dept. of Viticulture and Enology will be tasting 23 Zinfandels produced between the 1960s and the 2000s.

The first tasting happened last Thursday, July, 22.

The wines from the first week:

1967 Souverain Mountain Zinfandel, Napa Valley

1968 Mirrassou Zinfandel "Third Harvest", Monterey County (Tasting note from Fredric Koeppel here, created almost exactly 25 years to the day before we tasted these wines.)

1968 Louis M. Martini Mountain Zinfandel, California

1970 Souverain Mountain Zinfandel, Napa Valley

1979 Fetzer Zinfandel "Scharffenberger Vineyard", Mendocino

1980 Milano Lane Late Harvest Zinfandel "Scharffenberger Vineyard", Mendocino

1986 Kendall-Jackson Zinfandel "Zeni Vineyard", Mendocino

1991 Rosenblum Cellars Zinfandel "George Hendry Vineyard", Napa Valley

1991 Oak Ridge Vineyards Zinfandel, California

1998 Robert Mondavi Old VIne Zinfandel, Napa County

2001 Steele Old Vine Zinfandel "DuPratt Vineyard", Mendocino

Not surprisingly, the progression in age was the most notable aspect of the tasting. The old wines had the dried leaf, tobacco, musty, neutral flavor while the young wines had a fruity, jammy, oaky flavor.

Less pronounced by just as obvious was the shift in oak usage over time. The older wines (before 1990) had little or no apparent oak influence. As the wines got younger, oak began to play a much more pronounced role. My favorite wine, the Rosenblum, has just enough oak to let you know it was there, but not so much as to be considered a major flavor characteristic. The youngest two wines were almost completely oak dominated.

Another interesting note is the change in acidity over time; the old wines were very tart. We speculated that it may be because the grapes were picked less ripe. Other explanations involved the concept of field blending: When the Zinfandel grapes were harvest, other varieties interplanted in the vineyard were harvested and mixed in with the Zin. A high-acid grape like Barbera may be contributing to the acid structure. We also found a little bit of Brettanomyces going back to the vintages of the 1970's. Though none of the wines were medicinal or fecal, there was some barnyard-leather going on in a few of the wines.

The first week was an informative tasting. None of the wines were so dead that they were unenjoyable to taste. This week we will have 10 or 11 more to try. I will update with another post after that tasting.