04 SepHow Does a Late-Season Heat Spike and an Unexpected Rainstorm Impact the 2017 Vintage?

Posted at 19:30h in Uncategorized by: Wes Hagen 4 Comments 205 Likes Share

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This is the Best Kind of Rain to See During Winegrape Harvest!

Santa Barbara County vintages can be summed up in a single sentence: “Long, cool, consistent growing seasons punctuated by heat spikes in September and October.”

There have been a few recent vintages where we had heat in July/August, which shortened those vintages (2013-2015), but the wine quality miraculously did not suffer.

Vines are hardy plants that can survive amazing abuse, and even produce better wine with a bit of stress. Vines that were abandoned by humans have been found alive or nursed back to production after decades of neglect.  In other words, vines balance themselves when they must.

A very normal difference between a young winemaker and a seasoned veteran is how they react to unusual weather, especially heat and the threat of rain. Santa Maria just suffered through one of the most intense 4 day heat-spikes in modern history (it’s finally cooling down a bit today, 9/4/2017), followed by a night of unusual Summer rainfall.

Young winemakers usually show more anxiety in the face of crazy weather and tend to pull the trigger early, sometimes before a heat or rain event while the clusters are still physiologically unripe.  Some winemakers will pick during a heat-spike to keep the sugars from elevating without corresponding flavor advancement.  Veteran winemakers tend to let the weather pass, assess and work with their growers to get the irrigation and cultural practices timed perfectly, allow the vines to recover, wait for perfect physiological ripeness, and adjust the must as necessary with water or acid additions.

So in today’s Blog Post I hope to describe and explain a few things:

  • How heat-spikes impact vines, especially cool-climate varietals such as Pinot Noir
  • How rainfall does or doesn’t impact harvest decisions, disease pressure and wine quality.
  • How or if the heat and rainfall in the past few days will impact the 2017 vintage in Santa Barbara County, and Santa Maria Valley AVA specifically.

Santa Rita Hills, California;

Heat Spikes and Impact on Cool-Climate Wines, Pinot Noir:

Grapevines achieve maximum photosynthetic efficiency at 87 degrees F in full sunshine.  Vines close their stomata (leaf-pores that give off water vapor and oxygen), and fully shut down at 104 degrees F to avoid dehydrating and collapsing;  as well as heat stress and dehydration fears, the enzymes that carry out photosynthesis lose their shape and functionality at 90 degrees+.

But I can hear you, dear reader, asking for relevance:  “That’s very geeky, Wes, but I am just concerned about how my 2017 Pinot Noir is going to taste.”  No problem.  I have you covered.

Pinot Noir is very heat-sensitive, especially in the weeks leading up to a harvest decision.  In the heat-spike of 2010, which lasted almost 10 days, we saw 100 degree temperatures for nearly a week in the Santa Rita Hills and Santa Maria Valleys.  Wise viticulturists soaked their vines with a deep irrigation when the heat wave was forecasted, and continued to provide water to the vines throughout the event.  Even with deep irrigation, we saw Pinot Noir at Clos Pepe spike from 21.5 Brix (12.9% alc) to 25 Brix (15% alc) within 48 hours.  We went from expecting harvest in 2-3 weeks to full-scale picking within 2 days of the heat’s onset.

So did the 2010 Pinot Noirs show cooked, overripe character?  Some certainly did, but file it under irony that our 2010 Clos Pepe Estate Pinot Noir garnered mid-90’s scores and were the highest-rated wines we made at Clos Pepe.  Did the reviewers fall for the come-hither ripeness, dense color and flavors?  Of course they did.  The wine was super round and sexy, but lacked the depth and elegance I usually pursue in the craft of Pinot Noir wine-growing and making.

Fast forward to 2017 in Santa Maria Valley.  This has been the coolest, most wonderfully comfortable Summer in recent history, probably since 2009 or 2011 (two of my favorite vintages).  Without air conditioning in Santa Maria, we are very sensitive to heat, and before this last heat wave, we had not gone over low 80’s all Summer, and the average high temp was about 73 from June-August.

And here is the first vital take-home fact to remember:  Color, balance and flavor in Pinot Noir does not come from heat, it comes from cool temperatures and a long hang-time on the vine.  They do grow Pinot Noir in hot CA regions for cheap, awful plonk that can be accurately described by its varietal’s name.  But the greatest New World Pinots are all grown on the edge of ripeness–Sonoma Coast, Santa Rita Hills, Santa Maria Valley, Anderson Valley, Willamette Valley.  Extended, cool growing seasons produce the best wines in places where ripeness is almost guaranteed.

My belief (after 22 years of professional viticultural experience) is that heat spikes are like any human calamity.  When it’s happening, it can feel like the end of the world.  It pushes you to do unwise things in the moment.  But seen from the future, it’s pretty clear that Santa Barbara County can produce some pretty stellar wines in challenging years, and often these heat events produce dense and sexy wines that garner high critical praise.  Patience is a virtue, especially in the face of a weather event.

Heat damage in Pinot Noir, 9/3/2017, photo by Jasmine Hirsch

Heat damage in Pinot Noir, 9/3/2017, photo by Jasmine Hirsch

Summed up, heat waves in wine country have the following impact:

  • Sugar spikes due to dehydration and flavor development usually does not improve as quickly.
  • Winemakers, especially young ones, freak out and often bad decisions are made.
  • Wines picked before, in the midst and after the heat events are distinctly different, and critics generally prefer the wines that show higher ripeness, later picks, and wines that have been amended with water and acid at higher Brix (sugar).
  • Pinot Noir is the most heat-sensitive variety near harvest, and sugars can spike severely in temps above 90 degrees. (1 Brix a day)
  • Warm nights (in a region known for cold Summer/Fall diurnal shifts) can also rob Pinot Noir of acidity vis a vis respiration, so often times acidulation is necessary to replace the acid lost to night’s warmth.
  • Growers generally increase irrigation in vineyards to try to mitigate heat’s impact on the vines.
  • Other grapes grown in cool climates like Chardonnay, Syrah or Grenache can soak up a heat spike much, much better than Pinot Noir (without spiking sugars and plummeting acidity).
  • Picks tend to shift to night-time affairs, complete with miner’s headlights, lighted tractors and cooler fruit delivered.

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This amount of rain (5″+) could be devastating to a vintage, the .75″ we got was a refreshing drink after a hot spell.

Rainfall and It’s Impact on Winegrape Harvest

Last night was the first time in 23 years I saw measurable rainfall over .5″ in a single night in Santa Barbara County between June and October.  As far as worrying about rain during harvest, this is likely the best dry climate on the planet for bringing in sound, dry fruit.  So when I saw this morning that Santa Maria Valley vineyards received about .75″ of rain last night, initiating the end of our heat-spike in dramatic and thunderous fashion, I was more than surprised.  Worried?  Not so much.

I have said many times that rainfall under .5″ around harvest has a negligible impact on vine physiology.  It can increase fungus pressure, botrytis cinerea (noble rot) being the main culprit, as powdery mildew cannot grow on clusters after veraison (fruit softening).  But generally if you have your sprays down and you are watching the crop, a short rain event will not reach the soil depth necessary for it to become available to the vine.  3/4″-1″ of rainfall will reach the vine’s roots and will likely impact the vines by diluting grape flavors minutely.  A deluge, say 2″+ in a single day can certainly cause the grapes to take on water, flavors can be diluted and skins can even crack due to bulging. Most vineyards were likely watering through the heat event, so a little extra water won’t matter.

How is the Heat and Rain from the Last Week Going to Impact Vintage 2017 in Santa Maria Valley?

To sum up:

  • Even though no heat waves are always preferable for wine quality, Labor Day traditionally does usher in a spike in temperatures that usually last a few days to a week, can happen as late as November, and have an influence on style and ripeness in a vintage, but rarely threaten to ‘ruin a vintage’.
  • 2004 and 2010 are vintages strongly influenced by chronic heat-spikes.  2004 was more negatively impacted, with some cooked, overripe flavors in many Pinot Noirs from the region.  Most well-made Pinots from 2001, 2002, 2003, 2005 are still drinking well, but find a 2004 vintage and you may get some stewed fruit and tomato-skin characters that do not show in the other, cooler vintages.  2010 handled the heat much better because the ‘spike’ came almost a month later, the flavors were already developed and the wines became thick, jammy and dark–just what the critics love.
  • The short heat wave in Santa Maria in 2017 will serve to push harvest up a week or two for Pinot Noir, and will have a negligible impact on Chardonnay, Syrah, Grenache and other vine varieties that aren’t as heat sensitive as Pinot Noir.
  • Some Pinot Noir (and all the Pinot Blanc) were harvested for J Wilkes before the heat event, so we will have those as base blending wines to make sure if the other fruit comes in ripe to ultraripe we will be able to blend the wines into balance with minimal intervention.
  • The 2017 vintage has been marked with excellent Winter rainfall, good flowering and set, a beautiful moderate crop-level and minimal pest and disease pressure.  Four days of heat, followed by a refreshing night’s rainfall, will add more drama for the winemakers than change in the final quality of the vintage.  My backyard is already dry in the lovely 79 degree sunshine outside.   I expect vineyards to dry out completely this afternoon and this week we will expect to see Brix drop a smidge due to the rain, and then start recovering sugar to be picked at the perfect moment to make excellent wine.  Many folks were already irrigating through the heat spike, so a little water at root level should not make that much of a difference.
  • My sense is that 2017 will be the best vintage since 2012, as the good rain, longer hangtime and cool Summer will show clearly in the wines of Santa Maria Valley.  And I’m very happy to see normal, cool Summer temps return to my beautiful home in the Santa Maria Valley!

If you have any questions, comments, or arguments please leave them in the comments section!

Happy Harvest!

4 Comments

  1. Denise

    Posted at: Reply

    Thanks for such a sensible and informative article, Wes. I’ve been asked by several folks about the heat spike and its effect on this year’s harvest. this is very helpful!

  2. Jules Reuter

    Posted at: Reply

    A friend forwarded me this article. I was like, wow, this is helpful and well-written-sounds like something Wes hagen would write! Thanks Wes-love the blending of the geeky techie info with the practical “here’s the bottom line” info. As always, you rule-thank you.

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