By Amie Nemec
Last Saturday, my husband and I geared up in jeans, boots, hats, and long-sleeved shirts and drove up the road to Rustic Spur Vineyards. We were prepared to help out with removing the bird netting from their Tannat vines. If you don’t already know Ranae Mills and Jim Mills, they are an adorable couple from Central Texas who decided they wanted to retire and grow wine grapes. They first planted in 2013 and after their first harvest, they realized they didn’t want those little baby grapes to drive away and never see them again. So, they decided they should have their own wines made from their grapes. And what’s more, they opened a tasting room to not only sell their own wines but also showcase wines from small producers around the state. When you find yourself in downtown Fredericksburg, be sure to stop by Vintner’s Hideaway to try Rustic Spur and at least six other boutique producers making 100% Texas wines.
With the guidance of John Rivenburgh in the vineyard and his expertise in the winery, Rustic Spur wines were born. Their four acres of vines are planted in Tannat and Souzão bold reds with Semillon and Albariño whites. The weekend I was there, it was time to harvest the 1-1/2 acres of Tannat. The grape clusters were covered with netting to protect the fruit that was ripening from being eaten by birds. The nets are much easier to get on the vines than they are to get off. As the vines continue to grow their leaf canopies, those long shoots and their leaves can grow into the netting and tangle things up.
We started the project at about 6:30 p.m. with the Mills, their daughter, and vineyard manager Sherah, plus Ranae’s father, James, a family friend, and my dear friend, Laurie Ware. Laurie actually spent most of the day harvesting grapes in the hot August sun at another winery and still somehow mustered the energy to join us for some extra work that evening.
We had 12 rows to work on and by 9:30 p.m., it was a dark night and we had removed the nets from the 11th row by headlamps. Ranae threw some patties on the grill, and we nourished ourselves with burgers and wine. It was interesting to walk the full length of a row and see how the vines and the clusters compared to the previous row. As we relaxed after our field work, we discussed the rain clouds that were blowing in and the probability of rain that would affect the harvest planned for the next morning. Make no mistake, farming is no retirement plan! There is so much work and worry that goes into growing a vineyard.
On Sunday morning, Sherah and her grandfather got up early to get breakfast tacos for the family and promptly finished removing the bird netting from the 12th and last row of Tannat. By 9 a.m., the harvester was moving along the first row of grapes and efficiently shaking the grapes from the vine. The Pellenc harvester is state-of-the-art and quite a piece of machinery with a price tag that starts at over $300,000 for a basic unit. This particular tractor was owned by a local winery who makes themselves available for custom harvest work when they are not harvesting their own grapes. Sherah and her grandfather rode on the top of the machine looking down on the rows as leaves flew into the air and grapes dropped gently into the reservoirs on the machine.
As I arrived at 9:40 a.m., they had a full load after harvesting eight rows. Sherah ran the reservoir dump arm and emptied the grapes into the picking bins waiting on the trailer ready to be transported. Some other family friends were watching the fun and got to ride atop the harvester for the next four rows. There was even a professional photographer on hand producing images for the Texas Hill Country Wineries association. The air was full of excitement and anticipation as the grapes filled the bins and we all imagined wine in our future. Or maybe the feeling was simply the imminent rain, which the vineyard narrowly avoided.
Once the picking bins were safe and securely strapped down to the trailer, Sherah drove the truck to Kerrville Hills Winery. I followed behind just in case. It was a good thing too because she had a couple of issues with the brakes of the trailer locking up. Don’t worry, no grapes were harmed in the drive!
At the winery, the bins were weighed, and we took samples of the juice to get some beginning readings. From the 1.5 acres of vines, 4,560 pounds were harvested. A ton is 2,000 pounds, so we’re talking 2.28 tons of grapes. While this amount is quite a bit less than last year’s harvest, it’s nothing to bat an eye at considering the weather issues of this tough year. This initial testing of the juice showed 3.3 pH and 24.3 Brix. Back on August 8th, the fruit in the vineyard tested at 3.1 pH and 23 Brix. If this sounds a bit science-y, it is!
Brix is a measurement of sugar that ultimately determines how much alcohol the finished wine will have. In the vineyard, the grower or winemaker will use a device called a refractometer to identify the Brix in the grapes on the vine and determine if they are ready to harvest. The sugar level is determined by the specific gravity of the grape juice. Water has a specific gravity of 1, so Brix can be expressed as a percentage of sugar in the liquid. If a juice measures 20 degrees Brix, that means the liquid is 20% fermentable sugar. Remember, fermentation is where yeast eats the sugar to create alcohol. One way to determine if grapes are ready to be harvested is to measure the sugar levels. Roughly, the Brix number can be multiplied by 0.55 to determine what the final alcohol amount will be if a wine is fermented. As a general rule of thumb, white grapes are harvested at 20 to 24 Brix to yield wines of 11-13% alcohol. Red wines tend to be slightly higher in alcohol and we look for 22 to 26 Brix. If a grape’s Brix is too low, the final wine will be low in alcohol and higher in acidity. And the opposite is true. If a Brix reading is too high, the end wine will be high in alcohol and low in acidity, which may present issues with fermentation in the beginning staging of winemaking. The decision of when to harvest should never be based on Brix alone, but instead, it should be considered in conjunction with the pH and the actual taste and texture of the grapes.
And what about pH? Measuring the pH of grapes will provide a clue to the acidity and character of the finished wine. Acidity is vital to wine as it contributes freshness, acts as preservation and helps with microbial stability. The Potential of Hydrogen, or pH, and the Total Acidity, or TA, are both measured in grams per liter and tell us about the acidity in a wine. While TA measures the concentration of acid, the pH measures the acid strength. Acidity is quite important in the overall feel of the wine. Plus, a liquid with a high pH of 3.8 or more can be more likely to have bacteria flourishing and will affect the steps the winemaker takes in the cellar.
In a nutshell, the Tannat came in with pH and Brix levels that are within what a winemaker is looking for. And it tasted yummy! It was sweet and tart at the same time with no bitterness from the seeds within. From there, Sherah prepared the selected yeast to add to the grapes so they could ferment in the bins over the next couple of days.

Sherah Mills and Amie Nemec
After a full day of wine-ing, I was ready to head home but thoroughly enjoyed my day with the Mills and their 2021 Tannat harvest. This wine won’t be complete for nearly two years, but with the quality of these grapes, I have no doubt it will be a wine well worth waiting for.
About the Author
Amie Nemec is a longtime wine lover, Sommelier, and founder of Perspective Cellars tasting room in Fredericksburg, Texas. She is now venturing down the path to learn winemaking, so, along with wine writing and food pairing posts, be on the lookout for Amie’s wines in coming years!
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