A Wellington Wine Blog (of sorts) Part 5

What I Would be Doing This Month if I Hadn’t Retired

October
In the last installment I mentioned that the 2018 harvest was starting a bit later than usual. Now virtually all of September has been cooler than normal, and until this week picking and crushing has been progressing very slowly, with 10-20% of the North Coast grape crop harvested as of Sept. 22nd. Temperatures reached the high 80’s / low 90’s for four days this week, and I’ve seen a lot of grape trucks on the road for the first time this year. We might be ⅓ of the way through harvest by Sept. 30th. In light of this situation and last month’s column I’m going to focus on grape maturity and harvest decisions in this month’s blab.
The making of fine wine is inherently a complex process. People who prefer to simplify, generalize and interpolate can make excellent wine, but IMHO they don’t maximize the individuality of individual vineyards or regions. I call it winemaking by the numbers. If two different $100 (or $40 or $200) bottles of wine aren’t distinct from each other are they really worth $100? What I’m leading into here is that harvest timing (the most important decision in a wine’s life) becomes much more subjective in a cool, prolonged autumn.
At this stage of harvest there are a lot of vineyards that are “almost” ripe, and most of them will be harvested whenever the sugar and acid levels are at the wineries’ target levels. Things get more interesting with the vineyards that aren’t so close to being ready. Sugar and acid levels may be within the desired parameters for a week or two, while other compounds that influence aroma, flavor and structure might be increasing or decreasing very significantly during that time. Defining grape maturity in terms of desirability for winemaking is complex and varies depending on the winemaker’s stylistic goals. Sugar and acid/pH are the simplest components to understand; basically, time and heat cause sugar levels to rise and acid levels to fall. The effect of the sugar and acid levels on the finished wine is mathematically predictable. The effect upon the finished wine of all the other compounds in grapes is not mathematically predictable. The chemistry of both the phenolic and aromatic compounds in wine is strikingly complex. As of decades ago, over 800 aromatic compounds had been isolated from wine and identified. It really isn’t surprising when one considers the tremendous aromatic variation one perceives even in wines from the same region and grape variety.
Most of the many compounds that contribute to wine aroma increase, peak, then decline as the grapes mature. The rate of development and degradation of these compounds can be dependent on time, temperature, light or a combination of factors. We are talking about all grape based wine aromas here, both desirable and not so much. One year in the 90’s I had to make a tough call on our Merlot harvest. It was an early year with uneven maturity, so my biggest concern (based on walking through the vineyard daily, tasting grapes) was minimizing underripe (pyrazine – green pepper) and overripe (furfural - raisin) character. The tannins weren’t as soft as I would have preferred, but we were able to adjust for that quite a bit with an increase in whole berries, gentler pumpovers and earlier pressing.
In September’s blab I finished with this: The sum of information and understanding gleaned through multiple vineyard inspections also provides information that will be useful in decision making once the grapes are in the winery. Thinking of the tough call on the Merlot, these multiple vineyard visits also create a much better picture of flavor development, particularly regarding the rate of change of any given character. Changes in the levels of aromatic compounds and in the texture/mouthfeel of grape tannins don’t necessarily take place in a linear, or even predictable way. I’ve had many experiences, especially during cool periods of harvests, when the tannin structure and /or flavors of a vineyard changed very little for a week or two, then wow, without a heat wave or anything. You don’t notice these things if you aren’t watching. In depth knowledge of the grapes influences decision making in the winery primarily regarding tannin management and extraction in red wines. Variables start with adjusting the percentage of whole berries at the stemmer/crusher, and progress to choice of yeast strain; fermentation temperature; the technique, frequency and intensity of cap management; timing of pressing….Isn’t winemaking simple and easy?
By the way, if I were making wine this year I’d be excited right now. Weather conditions have been excellent for flavor development, tannin maturity and acid retention at moderate sugar levels. It is way too early to tell, but so far 2018 has the makings of a very good vintage for Sonoma and Napa.