BRUNSWICK — Green Bee Soda, the all-natural beverage start-up launched at Fort Andross in 2011, is adding unsweetened, flavored sparkling water to its product line.

The introduction, in partnership with the Maine-based, international restaurant chain Luke’s Lobster, has founder and Harpswell resident Chris Kinkade buzzing with excitement.

“We’ve seen demand now, and we think it’s going to be really big,” he said, speaking last week about the rising popularity of seltzer. “We have a lot of hope for sparkling water.”

He was sitting in the company’s 3,000-square-foot production facility in the basement of Fort Andross, where all the soda and seltzers are made in large, stainless steel tanks.

Kinkade said the new line of fizzy drinks isn’t too much of a departure from what Green Bee has been doing all along: making drinks from natural ingredients “with names you can pronounce.”

“One thing that drives me nuts,” Kinkade, said, is a bottle of colorless, flavored sparkling water.

“I don’t know of any blueberries that are crystal clear,” he said, “so how could that be all natural?”

Green Bee will initially produce waters with three flavors: ginger, lemon, and Maine blueberry (which is purple).

Most of them have about that many ingredients, too, Kinkade said, holding a bottle of his favorite flavor, ginger, and pointing to pieces of grated ginger that had sunk to the bottom.

Luke’s Lobster, which is based in Tenants Harbor, will be the only carrier of the seltzers at first, although Kinkade said Morning Glory, the natural foods store on Maine Street, will also offer a limited quantity.

Morning Glory was the first retailer to sell Green Bee’s honey-sweetened soda.

That was nearly seven years ago, when Kinkade, whose hobby was beekeeping, started making the soda for his children in his kitchen as an alternative to sugary commercial brands.

When the soda sold out, Kinkade, who had recently moved from his job on Wall Street to Harpswell with his wife, Lori, in search of a better quality of life, knew he had discovered what he was looking for.

The business has grown steadily every year, and while Green Bee is primarily in New England markets, the soda can be found as far away as Nevada.

Kinkade declined to share the company’s revenue, but said his small team makes “a couple thousand-gallon batches a week.” At one time products were shipped by the pallet, he said; now deliveries are made by the truckload.

Kinkade expects growth will accelerate with the introduction of sparkling waters.

In six years, Green Bee has only made soda, but Kinkade was inspired by the rising popularity of seltzers and his desire to provide a sugarless option to customers.

“We’re building the company to scale quickly,” he said. “(Seltzer) is where all the growth is happening in the market.”

He said there’s a segment of the population who appreciate what Green Bee is doing – “giving more authenticity to beverages” – but still “running from all things sugar.”

Kinkade’s honey-sweetened sodas tend to have fewer calories than some of their commercial counterparts, but some of the sparkling waters have as few as five.

“That way,” he said, “we have something for everyone.”

Callie Ferguson can be reached at 781-3661, ext. 100, or cferguson@theforecaster.net. Follow Callie on Twitter: @calliecferguson.

Chris Kinkade, co-founder of Green Bee Soda, left, with Director of Operations Randy Stevenson at their Brunswick facility Oct. 6. The 6-year-old company, known for its honey-sweetened, all-natural sodas, has announced it will start making flavored sparkling waters.

Ginger-, lemon- and wild blueberry-flavored sparkling waters are joining the product line at Brunswick-based Green Bee Soda.