Wines & Vines

February 2018 WINES&VINES 67 GRAPEGROWING WonderfulNurseries.com 661.758.4777 SERVING THE WINE, TABLE GRAPE, RAISIN AND PISTACHIO INDUSTRIES IF YOU WANT THE BEST, BUY FROM THE BEST. Every day, Wonderful Nurseries follows the philosophy that testing is believing. It's why we confidently offer the cleanest vines in the industry. In line with our "Growers First" philosophy, we have designed every element of our advanced processes & facilities to bring our grower partners peace of mind. This includes our intensive vine testing program, with 100% scion testing for internal mother blocks annually. Our in-house ISO Certified testing lab and built-in safeguards help accomplish this task. When it comes to getting the best in value, selection and cleanliness, Wonderful Nurseries delivers every time, vine after vine. RELY ON THE INDUSTRY'S CLEANEST VINES – 100% TESTED MOTHER BLOCKS © 2017 Wonderful Nurseries LLC. All rights reserved. WONDERFUL, WONDERFUL NURSERIES and the accompanying logos are trademarks of Wonderful urseries LLC or its affiliates. P.O. Box 279, 27920 McCombs Ave., Wasco, California 93280 infected grapes have matured ( s e e " Re d B l o t c h i s H a r d l y Noble"), the crew scatters across the vineyard equipped with nee- dle-nosed snips. "They recognize the difference between grapes infected with Botrytis and other fungi and molds," Allen says. "We discard the copper-colored ber- ries and raisins, looking for dim- pled fruit." If a storm threatens to destroy the crop, they pick the most dim- pled berries and leave the rest behind. "We harvest at an hourly rate of 15 pounds per person, with a yield of about 1 ton of fruit per acre," he says. How sweet it is At first, Allen picked by the num- bers, but he tossed out the refrac- tometer years ago. "It's a delicate balance," he says. "If we harvest the grapes too late, the juice may be both too concentrated with sugar and not have the acidity to offset the sweetness." Over time, the pH increases as acids are metabolized. While the mold consumes some of the sugar, ultimately the Brix in- creases as the berry dehydrates. Today, Allen and crew harvest to taste. "We sort the grapes in the vine- yard," Allen explains. "Berries that do not meet the day's harvest cri- teria are removed from the cluster. The crew places what's left into half-ton bins that they load onto flat-bed trucks and transport to the winery." John's Creek vineyard rewards those who wait. "The long hang time allows the grapes to produce many more metabolites, aromas and flavors than sweet wines made with rai- sins or distilled spirits that some winemakers add to stabilize the fermentation and balance the sugar-to-alcohol ratio," Allen says. By the time the grapes reach the winery, Botrytis cinerea has rewrit- ten the script. After evaluating three vintages from John's Creek vine- yard, Cantu discovered that noble rot induced Sémillon grapes to ex- press a unique combination of metabolic activities, some of which are more common to Cabernet Sau- vignon or Sangiovese grapes. History in the making A decade ago, scientists described the genome (or the complete set of genetic material) for Vitis vinif- era. They spelled out the chemical sequence of 30,000 genes found in 19 pairs of chromosomes, the rod-shaped structures containing tightly coiled strands of DNA. Within a single chromosome, millions of base pairs, which scientists abbreviate as a com- bination of A, T, G or C (ade- n i n e , t h y m i n e , g u a n i n e o r cytosine) join two strands of nucleotides to form a double helix. Each group of three nu- cleotide bases or triplet code (G-T-A, for example) produces a specific amino acid. Each se- quence of triplet codes or gene composes a precisely worded sentence that instructs messen- ger RNA (ribonucleic acid) and a ribosome to assemble amino acids into a protein that acts as a building block or catalyst for cell growth or fermentation. Unlike the Sémillon genome, which is fixed except for occa- sional mutations, a gene can vary the wording of transcripts based on details like soil moisture, vari- ety or whether a grape is infected with Botrytis cinerea. To understand how Sémillon grapes adapt to the fungus, Cantu explored the set of all transcripts or genetic instructions present in in- fected grape cells simultaneously. For Sémillon, Cantu's team de- tected an increase in transcripts from genes that regulate phenolic compounds including the red pig- ment anthocyanin. "Remarkably, " Berries that do not meet the day's harvest criteria are removed from the cluster." —Greg Allen, Dolce Winery

• Cover