Robert Hall Winery’s Regenerative Organic Trial: A Summary and Wine Tasting

In 2021 Robert Hall Winery started an exciting vineyard trial intended to prove whether regenerative organic farming practices would succeed in the winery’s estate vineyard. Regenerative organic practices require organic farming as a baseline — requiring certified organic inputs and prohibiting the use of synthetic herbicides and pesticides. Additionally, it uses ground cover along with no-till in the vineyard and requires animal integration.

The trial started with 48 acres surrounding the winery in Paso Robles AVA‘s Geneseo District. 43 acres were converted to regenerative organic and 5 acres remained as a conventional farming control, but with cover crops and compost added to the soil. Both the control and regenerative organic vineyards are planted to Clone 15 Cabernet Sauvignon. 

From the beginning the regenerative organic farming trial was intended to gather information to also share with it other growers and the interested public. I attended an early field day in the Robert Hall Winery vineyard in early 2021 that provided a look at what changes were being made in the test vineyard.

Robert Hall Winery not only recently announced the outcome of the trial with measurable results, but also announced the release of two Regenerative Organic Certified® wines. For the winery to become Regenerative Organic Certified® (ROC®) and release two certified wines, the winery went beyond the trial phase to the certification phase. It’s an important distinction. To achieve certification the winery has met USDA Certified Organic standards as a baseline, the Regenerative Organic Alliance (ROA) requirements for soil health, animal welfare and farmworker fairness, and achieved certification by ROA. They did the work and have the receipts. Congratulations on a job well done!

At the same time Robert Hall Winery is celebrating the one-year anniversary of the One Block Challenge™, which launched in Paso Robles in January 2025 with 46 growers who dedicated trial blocks to test regenerative practices together. The challenge is organized by the Regenerative Viticulture Foundation.

A Summary of Trial Results

• Water Retention: Water retention increased in the regenerative organic block by 13% in just one year — a significant finding in an increasingly warm and arid region.

• Soil Health & Biodiversity: Improved soil health and biodiversity in the regenerative organic block was demonstrated by more open, friable, alive soil with increased soil respiration, greater microbial activity and increased numbers of beneficial insects.

• Impact of Temperature: Cooler canopy temperatures were measured in the regenerative organic block during extreme heat spikes with a 7.8% decrease in temperature during one temperature spike. Lower temperatures prevent grapes from ripening too fast.

• Carbon Sequestration: Carbon sequestration increased by October 2023 in the regenerative organic block — it absorbed 192% more CO2 than the conventional block hinting at a role in mitigating climate changes.

• Yields: In three out of four years, the regenerative organic block produced increased yields, with a 15% increase in the 2024 vintage as compared to the conventional block. The regenerative organic vines produced 2.17 tons per acre versus 1.85 in the conventional block in 2024.

• Wine Quality: The regenerative organic block made wines with greater complexity, freshness, vibrancy and distinct Cabernet characteristics than the conventional block.

• Costs: Farming costs for the regenerative organic block increased an average of 10% annually, but Robert Hall Winery believes the increased yield and increased complexity of the wines the regenerative organic block made offsets the increased costs. The winery expects the regenerative organic vineyard to be more resistant to pests and disease, and climate unpredictability.

Let’s Taste

We received six Robert Hall Winery wines packaged in 187ml glass bottles by Master The World as tasting samples to compare the conventionally farmed wines and regeneratively farmed wines. We decided to challenge ourselves by tasting the wines blind–without knowing either the vintage or method of farming for the 2021 and 2022 vintage wines. We mixed up the four bottles, placed different-colored dots on the screw caps and poured them into wine glasses with the same-color dots, then tasted through them. I tasted first, made notes, then Pete tasted through them and I added his notes, without him seeing my notes. Our notes were surprisingly similar. Then we noted what vintage and farming method we thought each wine represented. Here’s what we tasted:

The Regenerative Farmed Cabernet Sauvignon from both vintages were more aromatic with generous fruit aromas and flavors that were also more complex and fruit-forward. The most complex wine of the group was the 2021 Regenerative Farmed Cabernet Sauvignon. The tannins were firmer in the Regenerative Farmed Cabernets. The Conventional Farmed Cabernets had good fruit flavors, but a different flavor profile — more leather and bramble with less complex fruit than the Regenerative Farmed Cabernets. All four wines had a medium body and good acidity, though the Regenerative wines tasted more juicy. What a fun tasting. We were definitely able to taste a difference between the two farming methods.

Then we tasted the final two wines from the 2023 vintage, both Regenerative Farmed, one Cabernet Sauvignon and one Petit Sirah also blinded just to see if we could tell the difference between the varieties. As you might expect, it was pretty easy to tell which was which just by the color in the glass.

2023 Regenerative Organic Farmed Cabernet Sauvignon — dark ruby in the glass with generous mixed berry aromas and flavors that include boysenberries blackberries, and a bit of earth with grippy tannins in a medium body. Great freshness with a juicy finish.

2023 Regenerative Organic Farmed Petite Sirah — ruby-violet in the glass with generous aromas and flavors of flowers, ripe blueberries and blackberries with a bit of sweetness. Tannins are very grippy in a medium+ body.

What’s Next?

Robert Hall Winery’s launch of their Regenerative Organic Certified® wines, a Sauvignon Blanc and a Cabernet Sauvignon available exclusively at Whole Foods (SRP $29.99), comes just in time for Earth Month and ahead of Earth Day on April 22. You will find more information about Regenerative Organic viticulture, farming practices and the two new Robert Hall Regenerative Organic Certified® wines on the Robert Hall Winery website.

Caine Thompson, General Manager at Robert Hall Winery who started the trial in 2021, will continue to share the results of the trial with interested members of the industry and public. Robert Hall is among six wineries in the Paso Robles AVA to recently become Regenerative Organic Certified® — Tablas Creek was the first winery in the world to become ROC in 2020. Thompson, who also manages sustainability across all O’Neill Vintners & Distillers’ properties, will integrate regenerative organic practices as part of the company’s overall sustainability efforts. When you consider O’Neill has winery estates in Sonoma and Paso Robles and a winery facility in Parlier, along with Ram’s Gate Winery, Robert Hall Winery, Line 39, Wines of Substance, FitVine Wine, Harken Chardonnay, Rabble Wine Company, Charles Woodson’s Intercept, No. 209 Gin, and BrandyLab, you can see the benefit could be quite significant within the company. O’Neill Vintners & Distillers is also a Certified B Corporation and received the Green Medal Leader Award from the California Wine Institute for its sustainability practices.

Thanks to Calhoun & Company for organizing our tasting.

Cheers!