Wine grape growing is not nearly so simple as plant a vine and watch it grow.

Think of a grapevine as a machine designed to produce a product. And “designed” is appropriate word. Vines that give us wine grapes today have been designed by human beings in same way breeds of horses, cattle, hogs, and dogs have been designed.

One of the most important instruments associated with this “grape machine” is a device called a “refractometer” that measures “Brix”—a number that represents the sugar content. One degree of Brix equals one gram of sucrose (sugar) in 100 grams of solution. Each gram of sugar will become about half a gram of alcohol.

In broad terms, the vineyard manager wants to achieve between 19 and 25 degrees of Brix. A Brix of 19 will produce an ABV of about 10.8%. A Brix of 25 will produce an ABV of about 15.1%.

Achieving the desired Brix is where a vineyard manager earns his keep.

There are myriad moving parts to hit the Brix target. Vine spacing. Water management. Trellising systems—cordon, guyot, pergola, lyre, goblet, basket, and more. Pruning is particularly important. You aim for 14 to 20 leaves for a two-cluster shoot. The proper number of healthy leaves (emphasis healthy), precisely aligned to sunlight is a critical component. Yes, it is that exacting.

Crunch comes as harvest nears. Vineyard managers scurry about, refractometers in hand, and make the most critical viticultural decision of the year. They load a small amount of grape juice into the refractometer. Raise it to an eye and see a refraction of light against a Brix scale. They also taste the grapes.

Then the moment. Like a military commander, the manager orders troops into the fields. For higher-end vineyards, the ideal window for harvest can be a single day. Often picking begins at night and finishes before heat of the day, but in any event will not end until all the grapes judged ready in a particular vineyard are in the winery’s crush facility. If all goes well, at the proper Brix.

Tasting notes:

• Nino Franco Rustico Valdobbiadene Prosecco Superiori DOCG: Great fruit, deliciousness, outstanding QPR (quality-price ratio). $18-20 Link to my review

• Stoller Family Estate Pinot Noir Dundee Hills 2018: Excellent aromatics. Very smooth easy drinker. $30-35 Link to my review

• The Prisoner Wine Company Eternally Silenced Pinot Noir 2017: Big, rich easy drinker. Velvety smooth in the mouth. Delicious. Vivid fruit. $45-60 (and can be discounted to mid $30s). Link to my review

Last round: I believe wine puns are in pour taste.