From sap to syrup

maple syrup collection
On a slow day, Horner’s Corner in western Wisconsin can still collect 650–700 gallons of sap from 2,500 taps connected between 8 miles of tubing. Photo by Jenny Heck

Surface tension, glaciation, barometric pressure, evapotranspiration and UV degradation aren’t necessarily terms you think of when talking about a Wisconsin family farm. But at a recent visit to a Horner’s Corner maple syrup operation, we learned all about the science going on in the maple woods this time of year.

Stephen Horner and his wife, Sandy, own Horner’s Corner, a 120-acre farm in western Wisconsin that consists of maple woods and a diverse orchard. Although as Stephen puts it, “It’s not farming, it’s an obsession.”

If you don’t remember from scouts or an arboretum field trip, for sap to “run” out of the trees, night temperatures need to be below freezing (but not too cold — ideally around 24 degrees) and day temperatures need to warm up to 10–15 degrees above freezing (but not too warm!) in order for sap pressure to build and cause movement inside the trees.

When we visited, it was a slow day. Stephen estimated they would be collecting 650–700 gallons of sap from 2,500 taps that are connected between 8 miles of tubing.

Once sap is collected, they remove 85% of the water through reverse osmosis before boiling it down into syrup. This high-tech, optional step reduces boiling time by roughly the same 85%, saving time and firewood.

Throughout our visit, Stephen lit up when describing his equipment, data and processes. His detailed care and knowledge of each element, from soil to bottle, can be explained, at least in part, by his previous career as an engineer. Despite his self-described “obsession” with maple syrup production, Stephen got into the work innocently.

“It all started for me 33 years ago on a Sunday morning,” he said, “back when there weren’t as many kids programs so [our family] was watching a PBS special on how to make syrup. That afternoon I decided to drill some holes, put some plumbing fittings in and see what happened.”

His experiment inspired a new business, which launched over 20 years ago when the Horners moved to New Haven Township. Stephen and his daughter Finley sell their Grade A maple syrup every Saturday from 8 a.m. to 1 p.m. at the Mill City Farmers Market along with seasonal fruit syrups, maple sugar, maple cream and even maple vinegar. These products are for more than pancakes; enjoy them as a natural and local sweetener for tea, coffee, baking, and cooking — like in the Maple Miso Dressing below. Learn more at

horners corner maple syrup
Photo by Mill City Times

Spring Greens with Maple Miso Dressing

Recipe courtesy of the Mill City Farmers Market. Serves 4–6.

Ingredients for the greens

  • 1 tablespoon olive oil
  • 1 tablespoon toasted sesame oil
  • 1 medium onion or 1 washed leek, sliced
  • 3 cloves garlic, minced
  • 1/2-inch piece of ginger, minced
  • 1 pound assorted greens (such as arugula, kale, mustard greens or spinach), washed and dried
  • 1 cup sliced or crushed almonds or other nut, toasted

Ingredients for the dressing

  • 1 tablespoon toasted sesame oil
  • 2 tablespoons olive oil
  • 1/4 cup miso paste
  • 1 tablespoon maple syrup
  • 2 tablespoons rice vinegar
  • 1 tablespoon stone ground mustard
  • 1 teaspoon soy sauce


In a saucepan, heat the oils over medium heat, add onions and sauté for two to three minutes until soft. Next add garlic and ginger and saute another minute. Add the greens handful by handful, stirring constantly. Saute until all the greens are added and they have wilted into a bright green — about two minutes.

Remove immediately from heat and place in a large bowl. Allow the mixture to cool, add the toasted almonds.

In a small bowl, whisk together all the dressing ingredients, then toss with greens and serve.