Cottonwood Part 3.
Making Arizona Wine
An intern was expected to arrive knowing his job and all the chemistry from the get-go. The protocols were demonstrated once by the laboratory manager, a tall and bright young man who seemed more serious than his years. He exercised admirable patience with the transition between awkwardness and competence at the chemical analyses.
The senior winemaker, not so much.
Colleagues back East had warned the intern about harvest winemakers face. At this time of season, the head winemaker survived on minimal sleep for his fourteen-hour workdays, and was stressed to turn around fruit that may be good or third-rate, into high quality wine. So, expectations of friendliness or helpfulness go out the window.
There was minimal frivolous chatter while people were hauling stacks of barrels, each barrel at six hundred pounds, with forklifts, pressing grapes in a machine the size of an eighteen-wheeler, running chemical assays, rinsing and sanitizing wooden barrels, or responding to the daily flood of data from dozens of fermentation vats with a plan top accommodate great as well as marginal grapes.
The largest custom crush operation in the state supported a crew of about six specialists: a head winemaker; a laboratory manager also trained in business and wine chemistry; a lab intern reporting to the lab manager; a cellar manager who sees to logistics of pumping, vats, barrel management, equipment hygiene and cleaning and forklift operations and two experienced cellar interns.
None have enology or viticulture degrees save the senior cellar intern from Washington State. One of the cellar rats is a Texan most recently from Hattiesburg, Mississippi, a former doctoral student there in physiological psychology with some plant karyotyping experience. The cellar manager chose wine over law school. The laboratory manager was an artist trained in computer graphics, and the winemaker had done a 4-yrear internship at Morissette in Virginia.
Barrels were juggled daily depending on the chemistry results. If fermentation is too fast, they are moved top the chilled barrel room. If too slow, they may go out into the noonday Arizona sun. The logistics resembled three-dimensional chess with fifty-five gallon wooden barrels as chessmen. To locate some small lots of one or a few barrels, the intern may have to crawl to the top of the six-barrel stacks with a flashlight to scout out those that needed sampling that day.
The intern rolls his cart past what seemed to be four-feet high impact plastic bins each containing a steaming, bubbling mass of crushed grapes. Sometimes, the bins were covered with plastic covers, at times with cloth. Or, some may be open depending on the stage of fermentation and temperature of the slurry called grape must. Grapes were also fermented in containers the size of above-ground plastic swimming pools containing about nine hundred to twelve hundred gallons. Extreme caution must be exercised when leaning over the lip of such fermentations, especially for novice winemakers. It was easy to be physically overcome by the thick blanket of carbon dioxide and alcohol vapors rising from the must of the fermentation vat.
More than one intern had tumbled headlong into the ferment. The situation was also hazardous for cell phones worn carelessly in the breast pocket.
The grapes floated on their juice as time passed.
Earlier in an adjacent building, the newly arrived bins have been emptied by forklift into a machine with a massive rotary screw that separated grapes from their stems. For red wines, these were collected again in bins and forklifted across the driveway into the wine cellar (a warehouse for wine production), and the intern finds himself chasing the forklift for a grape sample top analyze for sugars, acids, pH and other parameters depending on the type of wine to be made.
For sampling, a kind of collander has been provided which is pressed down by hjand into the grape slurry, and skin-free juice sluices in. A measuring cup served to scoop up enough liquid into a polypropylene graduated cylinder and its temperature is measured accurately. Then, what looks like a thermometer with a sealed glass bulb below it, was carefully dropped into the graduated cylinder and displaced juice runs over the side. The bulb bobbed and floated a little before reaching density equilibrium: the meniscus of the juice was then aligned with a specific number on the stem of the device called a hydrometer.
Grape juice had a lot of sugar in it, both table sugar (a two unit compound called sucrose) as well as the two component six-carbon sugars called glucose and fructose. Grape leave in the vineyard manufacture sucrose from sunlight in the process called photosynthesis, and this was fractured into glucose and fructose on transport from leaves through the phloem plumbing system of the vine, for storage in the ripening, maturing grape on the vine.
The sugars dissolved in grape juice rendered its physical density greater than water and their approximate level can be read off the hydrometer either as densities greater than 1.000 (pure water) or alternatively in degrees of Brix units. The sweetest grapes have been measured at about twenty-six degrees Brix and ripe petit manseng grapes were a good example. Most came in at nineteen to twenty-four Brix, most years.
All grapes had white or colorless juice: it was the skins of the grapes that held the pigments to be extracted giving the wine its characteristic color. Whereas whites were immediately pressed and skins separated from juice before fermentation, redes are fermented with skins as their color and pigments were extracted during a two-week fermentation period.
For white grapes, fermentation is cool and long. For reds picked later in the season, fast and hot. Red grapes fermented about twenty to thirty degree Celsius (sixty-eight to ninety one degrees Fahrenheit). At the upper end of this range, if the ferments became too hot, cooling coils may be lowered into the ferment to chill it to acceptable levels.
Reds were fermented in open-topped vats.
Whites were fermented in massive stainless steel twenty-foot tall enclosed cylinders of a thousand gallons, often incorporating built-in cooling jackets attached to a cellar wide plumbing system flowing food-grade ethylene glycol as coolant. Whites were fermented at sixteen degrees Celsius (about sixty degree Fahrenheit) a much longer and cooler interval than reds.
More important in white than reds were the volatile aromatic compounds which evaporated from the white ferments if too hot. Such aromatics were what lent white wine its enchanting, memorable aromas in the bowl of the wine glass.
On the other hand, reds required more, but not too much, heat to extract color compounds form the red grape skins.
(…to be continued…)