A Glass of Wine at Petersen

28 December 2017 Written by  By Peter Petersen
Published in January 2018 Articles

My wife and I are owners of Petersen Vineyards in Knightsen, which is a family owned estate winery with an annual yield of about 2,000 cases of wine and we could go as high as 4,000.

We are almost the only winery in the area that grows, processes, and bottles our products right on site. We do a lot of the work ourselves. In case of crunch time problems, we ask friends, family members, and contract workers, as required. 

The Petersen Vineyards location is situated with a view from the winery of Mt. Diablo’s changing moods, which are always interesting, often lovely, and on many evenings beautiful beyond words. The vineyard retains some of its rustic character as a farm site. We are a family affair because my wife, our five children, and I manage the business and do a large part of the actual work. 

Twenty-seven-year-old Britany and 16-year-old Nicolai especially love working in the business. We do not yet have a public tasting room, but offer private tastings by appointment at our facility. We make this fun and unique. Our guests taste from the barrels, taste from the tanks, and of course from bottles. 

Our Petersen Vineyards wine club offers our products for a discounted price, as well as a number of other benefits including VIP level participation in release events and other winery sponsored special occasions including a mid-summer BBQ & Wine Event, a fall Harvest Event, a winter Holiday Festival, and others. We also offer tasting events held onsite and at local wine bars. Britney, our oldest daughter, has brought in the most wine club members. Our winery is open for private tasting parties plus private celebrations and festivals of any kind. Through our onsite services and special events we want to offer genuine winery experiences that emphasize the art of winemaking. 

We sell Valdepeñas wine, which is made from a grape found only in Spain. It was brought to California by some unknown winemaker and then neglected. For 120 years the story of the grape was lost until researchers at UC Davis conducted some DNA research and discovered its origins. They classified it as an official varietal and winemakers used it to make ports. We have also created a 2016 Petite Sirah. Even though it has barely aged for a year, the grapes were taken at exactly the right time and the wine is already delicious. 

We are also bottling a Knightsen Ruby dessert wine, which is an incredible port. Another port has the fanciful name Bombordo, which is the Portuguese word for Port Side. The name has a history because my great great grandfather and his four brothers left Denmark to sail the world. All five of them were professional ship carpenters and were sailing in the first boat they built themselves. 

My Danish parents were fans of port wine, and I am a big fan myself. A good port is more than a mere dessert wine. It doesn’t have to be sweet. Just as salt and pepper will bring out the flavor of a steak, a fine port will enhance the flavors and aromas of the grapes used in its creation. Creating premium port wines was an important part of my purpose in becoming a winegrower. I want Petersen Vineyards to become the Contra Costa go-to place for port wines. Portuguese port styles have unique characteristics from Portuguese varietals. We obviously can’t grow our grapes in Portugal but use customized plantings for our port products. We also mix them with some Spanish varietals to make some fantastic red blends. 

One of our most popular wines is a Chardonnay Port Wine that we created by accident. Our second oldest daughter, Sara, was getting married in 2015 right when we were supposed to harvest the grapes. She married a Hispanic man and we had a number of guests from Denmark and Mexico, as well as the United States. By the time the wedding was over and guests had departed we had missed the harvest, but made 100 liters of wine using the late grapes that by that time was yielding 28 percent sugar levels. We fortified the grapes to port and then watched as the blend seemed to assume a life of its own. One month it tasted of pear, the next month mango, and apple during the subsequent month. We finally put it into oak barrels. At cooler temperatures the resulting port had different characteristics than when it was warm. 

We named the final product Pura Vida, which roughly translates to the “pure life” or “all life,” and in Costa Rica is a line commonly delivered to a friend when departing. We were delighted with the results of our serendipitous adventure. For example Pura Vida can be poured over ice cream and fruit for an amazing treat. Fortunately, we kept careful notes on the progress of the “accident,” so we could replicate the taste and are doing a brisk business with the 2016 bottles. 

I learned during my research the dismaying fact that the mechanical processing equipment used by the factory size wineries includes significant amounts of MOG, which is the industry’s acronym for Material Other than Grapes. MOG can amount to as much as seven percent of the material in machine-based processes and is composed of stems, leaves, bits of bird nests, insects, and other materials that we wouldn’t like to think about. 

I was put off by the discovery so I designed a five-stage process using appropriate equipment that removes nearly every bit of MOG, leaving only the grapes themselves to be processed into wine. Knowing that our wines contain none of the debris included in many other wines appeals to our senses but, even more importantly, the purity of the material at the front end of the process removes some of the harsh, bitter, and biting tannic qualities that would otherwise be present. As a result, our wines have a smooth quality with a pleasant mouth feel. 


I grew up on a Danish dairy farm and might have spent my life milking cows in Denmark. However, my father told me that I could do anything with my life that I chose, as long as it wasn’t dairy farming. So I studied electrical engineering and spent a few years designing Danish cell phones. Of course, Silicon Valley is the heart and soul of the electronics revolution that was changing the face of civilization, so I moved to California and got involved in a couple startups. 

Someone said that only one startup out of seven becomes a stable business. I beat the odds because after riding one company down in flames, I joined the initial team in a company that set out to design test equipment for the new Wi-Fi technologies that were coming to market. We were LitePoint and became the world’s leading Wi-Fi test equipment manufacturer and the main supplier for big players such as Apple and Intel. In 2011 we were sold to Teradyne. 

I made enough cash from the transaction to follow a long-time dream, to do something that would involve family and agriculture. In 2011 I purchased the Knightsen property and was drawn to growing grapes. The first batch was bad, and I was determined to make it better. That was when I became a winemaker. Some people might have imagined becoming a winemaker to be a foolish ambition because I had no experience in the wine industry and knew absolutely nothing about how grapes are grown or about the processes by which they are then transformed into wine. However, I am a lifelong learner and a firm believer that any intelligent person with sufficient entrepreneurial passions can utilize the rich resources available in our Information Age to learn to do anything he/she makes up their mind to do. I have a lifelong love for learning, so I was eager to master the entire vine-to-wine range of the winemaker’s art, beginning with preparing the ground for new grape plantings all the way through wine-marketing techniques. It helped that I was able to approach the challenge with a regard for getting details right that I carried over from my profession as an electronics engineer. 

We became Petersen Vineyards, which now sits on 20 acres — three acres of which are cherry groves and 12 acres of vineyards. I designed a public space, which is a volume room with interior decorations including faux windows and walls on the upper level of the space and lower walls decorated in elaborate patterns created from 14,000 pieces of used tile that I purchased for $700. I did almost all of the designing and decorating work myself. 

One of the realities creating opportunity for small winery success is that winemaking is more art than science. Of course, winemaking involves chemical equations that, with my engineering background, I could easily understand and manipulate. However, the finest test equipment or most complicated algorithms can never guarantee a premium product. As a result, small wineries like Petersen Vineyards have the potential to deliver wine of superior quality compared to the large factory-size wineries that rely on cookie-cutter “by the book” winemaking processes because their products are often mediocre and, in some cases, are failures in the opinion of any discriminating palate.

Successful winemaking involves a number of things that can’t be learned from a webpage, so I enlisted the aid of a good friend and an amazing mentor, Alan Lucchesi, who taught me to grow and manage the wine plants. I joined his teams of hardworking skillful Mexican farmhands in the field who taught me necessary techniques for planting, training, pruning, suckering, and caring for vines. They were generally patient teachers who taught me a lot about the trade, and even taught me a bit of Spanish.

The next part of the learning was actually making the wine. You can find accurate how-to information on Google and YouTube for almost anything, and I learned a lot of details about harvesting and processing wines, plus I picked the brains of any winemakers who would talk to me. 

In 2014 I made a Petite Sirah and Zinfandel blend. We wanted to brand it with a name and logo that would suggest our location. One of the kids came up with the perfect name, Diablo Sunset. The label features an actual Mt. Diablo sunset scene as it was painted from pictures taken from the door of our winery on a fine March evening. We were all excited by our first success. 

Our friends praised our beautiful label. More importantly, they also praised the taste of the wine. We also bottled our first port-type wine that turned out to have an amazingly light taste and was so good on the palate that some dessert wine enthusiasts have pronounced it the best they ever tasted. 

We were bonded in 2015 and began retail wine sales in 2017. We obviously hit the ground running because our wines have already won some awards. 

We plan to continue building a reputation for fine wines here in Contra Costa and grow in size as people learn about our premium products. 

Call and make an appointment for a tasting at the winery or sample our products at Brentwood’s Co. Co. County Wine Company, Zephyr Grill and Bar, or Back Roads in Discovery Bay. You Can learn more about Petersen Vineyards from our website: www.petersenvineyards.com

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