Interview with Local Expert, Mr. Jon Rowley



















Jon Rowley is a gustatory polymath whose expertise includes wine, shellfish, fruits, vegetables, and more. We spoke with Jon about his work with local fruit and vegetable growers, high-end supermarkets, and the other clients he helps to maximize the quality and flavor of their produce.

There are plenty of ways to gauge the quality of fruits and vegetables, but in his work seeking out the best flavors, he finds the refractometer indispensable.

 Refractometers are devices that measure how much a beam of light bends when it passes through a substance, e.g. the juice of a peach or tomato. The more the light bends, the more dissolved solids are present in the substance. For fruits and vegetables these solids are an excellent indicator of the sugar content in their juice. This observation forms the basis of the Brix scale, which is widely used to gauge the sugar content of all kinds of solutions.

“Photosynthesis is a plant’s job. The resulting glucose molecule is the chemical foundation for everything manufactured in the plant. The refractometer measures the success of the plant.” 

The key take-away from this, as Jon succinctly explained, is that “high Brix means high varietal flavor.”


This simple rule is just the starting point for understanding Jon’s more nuanced work in which he profiles the broader relationship between Brix and flavor. Jon uses a refractometer and his expert palate to create charts that match a range of Brix values to the changing flavor profile of different fruits and vegetables.

The chart he prepared for yellow peaches is used during an annual promotional event at a chain of high-end supermarkets in the Seattle area to help customers know exactly how sweet the fruit on display will be. Peaches need to have a minimum of 13% Brix to even make it to the multi-week event, but their testing doesn’t end there. “We take samples from five peaches every day and post the results,” Jon explained, adding that customers can then refer to the prepared chart to see an enticing description of what they can expect the fruit to taste like.

For anyone interested in following Jon’s example, measuring Brix is something anyone can do. Anyone with a home garden or a love of cooking can use a refractometer to get the best from their ingredients, too. “I don’t understand why every kitchen doesn’t have one,” Jon mused. He noted that he has used different refractometers throughout his career, and quite simply he “came to ATAGO because the others kept falling apart,” adding that he finds the bright measurement display on his analog refractometer “much easier to see.”

By measuring a number of different tomatoes, for example, tasting them, and logging the findings, a clear picture begins to emerge of how the flavor improves as Brix increases. “A large tomato needs to be 5% Brix to taste like a good tomato. At 6% Brix a brightness comes into the flavor,” Jon explained.  “As the Brix level increases the flavor intensifies and the texture improves with higher density.


This method of experimentation can be applied to all sorts of produce, and can even be adapted to monitor how differences in sunlight, watering and soil quality can have an impact on flavor.

All it takes to get started is fresh produce, a log book, and a refractometer.


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