Foraging for Salinity

“Not without salt!” It’s the manifesto of many chefs. But for Brian Mercury, upon reading former Spago Pastry Chef Ashley Rodriguez’s blog of the same name, it turned out to be a calling. When Rodriguez posted an article about making homemade salt, Mercury wondered if he could incorporate such briny localism into the pastry kitchen at Harvest in Cambridge, Massachusetts.

He started on the southern tip of Maine, a big orange bucket from Home Depot in hand. “I was looking for a spot away from too much commercial action.” But Mercury soon found a beach a little closer to home in Gloucester, just across an inlet from … Salt Island. He makes the trip once a month and harvests 10 gallons of sea water, which yields 8 to 10 cups of salt.  

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In the kitchen, Mercury boils the water in 5 gallon batches. “The slower you do it, the larger the crystal,” he says. (If you’re looking for finishing salt, take heed.) In Mercury’s kitchen, however, they boil it hard for 5 to 6 hours in a clean, aluminum-free pot: “Any dirt or discoloration will give the salt a gray or brown look,” and aluminum causes a similar discoloring reaction. Another imperative: thoroughly strain the water to avoid a salt infused with sand, shell particles, seaweed, and stowaway sea creatures. He also says it’s important to closely monitor the process once the water reaches the 1 gallon mark to avoid scorching. And be careful of “sputtering,” says an all too wary Mercury, “boiling salt is hot!”

As for the salt’s applications, the proof is in the pudding—or rather in the crémeux. Though Mercury tried using his “White Gold” in breads, he says the nuances of New England salt’s heavy minerality and peppery-ness fell flat. It fared better when his team smoked it and whipped it into butter for a James Beard dinner; it also makes its way into the restaurant’s nut butters.

But the star that showcases his efforts best is Harvest’s Taza chocolate crémeux. Just a pinch goes into the crémeux batter, which hides a lush salted caramel core. The plate is finished with an Oreo cookie crust, brown sugar granola, gently sweetened mascarpone, malted milk chocolate sauce, and a finishing sprinkle of Mercury’s salt flakes. Since Mercury’s saline-forward dessert appeared on Harvest’s menu in June 2012, he estimates that the restaurant has sold more than 14,000 orders. They make 40 crémeux at a time, five days per week.

In addition to his Boston base, Mercury has foraged for saltwater in Florida, and has received salt parcels of varied origin from former employees. But, he says, “There’s more character to New England salt,” the rocky terrain lending greater nuance than Florida’s flat, sandy beaches. When presenting salt as an ingredient in its own right, one with such distinctive terroir, why not source it from your own back waterway?