TL;DR: Winemaking produces significant organic byproduct, primarily pomace, the skins, pulp, seeds, and stems left after pressing. At Etude, pomace is composted with carbon-rich materials and applied to vineyard soil using no-till farming practices, feeding a thriving microbial ecosystem that improves vine health, water efficiency, drought resistance, and ultimately contributes to the flavor and terroir of the wine. Etude is Certified California Sustainable Winegrowing (CCSW), independently audited annually across more than a dozen criteria. March 18 is World Recycling Day.
The Most Important Thing We Throw Away
We will be honest: talking about winery waste does not have obvious glamour. But once you understand what actually happens to the leftovers from winemaking, it becomes one of the most interesting parts of the story.
This is a closed loop, and it is working.
The Numbers: What a Bottle of Wine Leaves Behind
| Winemaking Fact | Detail |
|---|---|
| Grapes per bottle | Approximately 600 to 800 grapes |
| Bottles per vine | Approximately 10 |
| Primary byproduct | Pomace: skins, pulp, seeds, and stems after pressing |
| Key nutrients in pomace | Nitrogen, phosphorus, potassium, calcium |
| Composting materials added | Straw, shredded vine clippings, waste wood chips |
| Application method | Surface applied under no-till farming practices |
It takes somewhere between 600 and 800 grapes to fill a single bottle of wine. That works out to roughly 10 bottles per vine. What remains after pressing the juice is called pomace, and if you farm for a living, it is one of the most valuable things in the winery.
What Is Pomace and Why Does It Matter?
Pomace is the collective term for the grape solids left behind after juice extraction: skins, pulp, seeds, and stems. In many wineries, it is treated as waste. At Etude, it is the beginning of the next vintage.
Pomace is naturally rich in nitrogen, phosphorus, potassium, and calcium, the essential nutrients plants need to grow. It also contains organic compounds that support the bacteria living in healthy soil. When combined with carbon-rich materials like straw, shredded vine clippings, and waste wood chips, pomace composts quickly into a well-balanced soil amendment that is, in effect, purpose-built for growing grapes.
The result is a nutrient cycle that starts in the vineyard, moves through the winery, and returns directly to the soil. What the vine produces feeds the vine again.
No-Till Farming and the Microbial Ecosystem Beneath the Vineyard
At Grace Benoist Ranch, Etude practices no-till farming. Rather than plowing or turning the soil between growing seasons, we leave it undisturbed. At the surface level, this reduces erosion and allows vine roots to grow deeper, which increases drought resistance in a region where water management is an ongoing priority.
The more interesting story is underground.
The composted pomace is applied to the top of the soil rather than mixed in. This surface layer does two things simultaneously. It holds moisture at the soil surface, reducing the need for irrigation. And it slowly filters nutrients downward into the living community of microorganisms in the soil below.
Those microorganisms, bacteria, fungi, and other microbial life, are among the most important contributors to what makes Etude's wines taste the way they do. While consuming the compost themselves, these microbes convert the nutrients into forms the vines can more readily absorb. A thriving, diverse microbial ecosystem helps vines use water more efficiently, protects them from harmful pathogens, improves drainage and airflow through the soil structure, and contributes directly to the flavor profile and character of the wine, what winemakers call the vineyard's unique terroir.
Soil health is not separate from wine quality. It is where wine quality begins.
Certified California Sustainable Winegrowing: The Accountability Framework
Beyond composting and no-till farming, Etude participates in the Certified California Sustainable Winegrowing (CCSW) program, an independently audited, third-party certification that holds member wineries accountable across a comprehensive set of sustainability criteria.
The program functions, as we have described it internally, like a sustainability workout partner. It is a network of vineyards and wineries that believe sustainability matters and hold each other to international best practices for growing and crafting quality wine while protecting the environment and being good neighbors and employers.
The annual certification and recertification process is rigorous. Independent auditors verify performance across criteria that include:
- Water efficiency
- Energy efficiency
- Soil health
- Waste management
- Wildlife habitat
- Employee experience and wellbeing
- Pest management
- Community giving
- Year-over-year improvement
- Supply chain accountability
Audit results are published in the program's annual report. The process asks a great deal of the Etude team each year. The benefits to the land, the community, and the quality of the wines make it worth it.
World Recycling Day: What You Can Do
March 18 is World Recycling Day, and the simplest sustainability contribution most households can make is also one of the most overlooked: make a grocery list and stick to it.
Thoughtful shopping reduces waste at every point in the food supply chain. If you have leftover ingredients from the week's meals, challenge yourself to use them before buying more. Soups, grain bowls, and improvised pizzas are some of the most satisfying things to make with what is already in the kitchen.
For food waste that cannot be avoided, check whether your community offers a composting pickup service. Many municipalities in California now do.
And of course: put your Etude empties in the recycling bin. Wine bottle glass is 100% recyclable and can be reprocessed indefinitely without any loss of quality.
FAQs: Winery Waste, Composting, and Soil Health
What is pomace?
Pomace is the organic material that remains after grapes are pressed for juice: the skins, pulp, seeds, and stems. It is the primary solid byproduct of winemaking and is rich in plant nutrients including nitrogen, phosphorus, potassium, and calcium.
How does Etude use pomace?
Etude composts pomace by combining it with carbon-rich materials such as straw, shredded vine clippings, and waste wood chips. The resulting compost is applied to the surface of vineyard soil at Grace Benoist Ranch as part of a no-till farming program.
What is no-till farming and why does Etude practice it?
No-till farming means leaving soil undisturbed between growing seasons rather than plowing or tilling. At the surface level, this reduces erosion and allows vine roots to grow deeper, building drought resistance. Below the surface, it preserves the structure and diversity of the microbial ecosystem that is critical to soil health and wine character.
How do soil microorganisms affect wine flavor?
A thriving, diverse microbial community in vineyard soil converts nutrients into forms vines can more readily absorb, supports water efficiency, protects against harmful pathogens, and improves the physical structure of the soil. These factors collectively influence the flavor, aroma, and character of the wine, what winemakers refer to as terroir.
What is the Certified California Sustainable Winegrowing (CCSW) program?
CCSW is a third-party sustainability certification for California vineyards and wineries. Member wineries are independently audited annually against criteria covering water and energy efficiency, soil health, waste management, wildlife habitat, employee wellbeing, pest management, community giving, and supply chain practices. Results are published in an annual public report.
Is wine bottle glass recyclable?
Yes. Wine bottle glass is 100% recyclable and can be reprocessed indefinitely without any loss in quality. Place empty Etude bottles in your curbside recycling bin.
What can individuals do to reduce food and packaging waste?
Shopping with a list reduces over-purchasing and minimizes waste throughout the food supply chain. Using leftover ingredients before buying more, composting food scraps where possible, and recycling glass, paper, and cardboard consistently are among the most impactful individual actions.
Learn more about Etude's sustainability certifications and practices at etudewines.com/pages/sustainability.
Pour & Protect.