AT DINNERTIME LAST WEDNESDAY EVENING, East Hampton’s Rick Rinaldo told a caller that he couldn’t talk at the moment. He was otherwise engaged.

Making soap.

He was in the basement of his family’s Flat Brook Farm home, his daughter Kim, 22, explained a few hours later. Specifically, he was mixing milk from one of the goats on the farm with lye and a combination of coconut, olive, and palm oil, adding a fragrance, and pouring the concoction into a block mold.

His family’s soap making demonstration at Saturday’s Harvest Day at the Dudley Farm will be a treasured memory by the time the mold has solidified enough to cut it into blocks, and those blocks are cured for a minimum of three weeks, and then packaged and labeled as hand-crafted Flat Brook Farm Goat Milk Soap.

As will the candle making techniques of Colonial tradesmen and housewives re-enacted by Norwich’s Bob and Melodye Whatley which are also slated for Saturday’s celebration. Not to mention their answer to the burning question they guarantee to pose: whether lighting elements of the past are as energy efficient and environmentally friendly as today’s sources.

And while the soap that Rick Rinaldo was making last Wednes-day night will take only weeks to mature, it was all the way back in May that Janet Dudley and her husband Mark were planting corn on the fields of Dudley Farm.

Unlike seed commercially developed to ensure uniform size and ripening time, with taste and flavor secondary considerations, the so-called heritage seed is meant to be harvested by hand, not by machine and, as it happens, is the same variety that was grown at the farm in the late 1800s.

It’s all of a piece with the larger mission of Dudley Farm, a nonprofit 19th-century farm museum and educational center located at the intersection of Routes 77 and 80 — to honor and sustain Guilford’s rich agricultural past while affording its visitors a chance to experience first-hand the simple farming life of two centuries ago.

As with earlier generations, Harvest Day, falling on the second-to-last farmer’s market of the season, is an opportunity to stock up for winter with jams, jellies, pickles and maple syrup, as well as wool blankets made from Connecticut sheep.

Hence, the focus of this year’s celebration, according to Janet Dudley, president of the Dudley Foundation - to bring to life the domestic necessities farmers and their families prepared during the harvest season for the cold, dark months ahead.

That includes staying warm, as Dudley herself will exhibit, with the basic hand spinning techniques employed on both an 1860 wool wheel and an 1830 flax wheel in order to process fiber from raw fleece into yarn for blankets and clothing. In accordance with “the hands-on, living museum” that is Dudley Farm, she said, visitors can try their hand at carding wool and using a drop spindle.

Not so with draft animals Bob and Dave, though Mark Dudley and his son Evan promise to make introductions to anyone interested in meeting a pair of strapping 4-year-old Brown Swiss oxen trained from the age of 2 weeks to respond to voice commands and listen attentively to a discussion on their historical importance to a farm.

Whether Bob and Dave will make their way through the peddlers peddling amid the lively bluegrass tunes of the Dudley Farm String Band to the Rinaldo family’s goat milk soap making demonstration has yet to be determined.

If they do, the two beasts of burden will learn of the benefits of goat milk soap for dry or sensitive skin or conditions such as eczema; that’s because it contains lactic acid which helps remove dead skin cells from the skin’s surface, Kim Rinaldo said.

Sure, goat milk soap might not have been part of a 19th-century farm wife’s provisions for the winter—or her beauty regimen, for that matter. But it’s still a “way of getting back to nature,” as Kim Rinaldo put it.

Not to mention, in keeping with Harvest Day, an occasion to enjoy the fruits of one’s labors.

Harvest Day at the Dudley Farm, will be from 9 a.m.-2 p.m. on Saturday at 2351 Durham Road in North Guilford. For more information, visit www.dudleyfarm.com or call 860-349-3917. To learn more about goat milk soap, visit www.flatbrookfarm.webs.com.