On August 18, during a veraison green-thinning pass through the upper vineyard, we collected 260 pounds of partially-purple, but still unripe grapes.

It's called green-thinning because the grape clusters that are not as far along in their color development (there are still green and light pink berries throughout the cluster) need to be cut. Since the harvesting of winegrapes takes place all at once, it's important for all of the grape clusters throughout the vineyard to be evenly ripe. The clusters that we cull from the cropload would not be as ripe as everything else. At left is an example.

Thankfully, we have come up with a fabulous use for a portion of these clusters that would otherwise rot on the ground: verjus!

The process of making verjus is similar to winemaking -- pick grapes, crush, press, rack, and bottle. But instead of being stretched out over the course of 12-18 months, since verjus does not need color extraction, fermentation, or barrel aging, we completed the production (except for bottling) in about 8 hours.

We washed and lubed the grape crusher/de-stemmer, setting it atop a 30 gallon bucket set outside the winery and vineyard tool bay of the garage.

John shoveled the grape clusters into the hopper, while Deb operated the hand crank, crushing the grapes into the bucket.

With a press borrowed from farmer and winemaker and neighbor Dan Sanchez, John added the crushed grapes and their juices by shovelsful into the press.

John cranked the press, and you can see the juice starting to flow from the juice tray's spout into the catch basin.

There was one noticeable difference in this year's batch compared to our very first production last year: the color of the free run juice started as green. This makes sense since the inside of the berries is green and the juice had minimal contact time with the dark red skins of the grapes. Last year, the juice sat with the skins a little longer so all the juice was pink immediately.

You can see in the second photo that even a little contact time lent some color, so the later juice was pink.

The 260 pounds of grapes produced 12 gallons of verjus after the initial pressing. This photo shows the progression of color as we got further down in the batch, and the juice had more and more time in contact with the skins.

Our plan was to blend them all together in the first racking, scheduled for two days later after the solids had a chance to settle to the bottom.

On Monday morning, we pumped from the 4 carboys into a large bin, leaving the inch of sediment (grape solids) in the carboys.

John measured out a few grams of potassium sorbate, which he dissolved into the liquid to stabilize the juice and prevent fermentation. And for you data-freaks, a few measurements in the chemistry lab in our home winery told us that the brix (sugar) level was at 12, and the pH, 2.8.

The verjus was then pumped back into 3 carboys, with the total volume reduced to 11 gallons with leftovers of a bottle-and-a-half, which went right into our refrigerator for immediate use!

With the blending, the color was a uniform pink. We'll do another racking to remove another layer of solids, and then we'll bottle.

• Fill a short cocktail glass with ice cubes
• Add 1.5 ounces Campari, 1 ounce of verjus, and top with sparkling water
• Stir, garnish with orange peel

John uses it in place of wine or other liquids in cooking, especially if it's a vegetarian dish. Add a quarter cup to a stovetop saute for the last five or ten minutes of cooking. The verjus adds a touch of sweetness, a light acidity, and a great depth of flavor.

Terra Sonoma Food Company: www.terrasonoma.com

Epicurious (Gourmet and Bon Appetit magazine site): www.epicurious.com

And of course, the Food Network site: www.foodnetwork.com