NILES — Iron Shoe Distillery employees arrived to work an hour before opening Saturday morning to find a line of people at the doors of the business. They wanted its limited liquor, to be released at the distillery’s 11:30 a.m. opening.

The supply of Iron Shoe Distillery’s first whiskey, a year in the making, immediately began to diminish once the doors opened.

The liquor’s launch was proof that there is nothing risky about the bourbon whiskey business. Howard Tuthill, co-owner, said whiskey, bourbon especially, is in an upswing of popularity. His appreciation for it was why Tuthill started distilling, and now others are enjoying it, too.

“Laura and I are really excited about this,” he said, referring to his wife and co-owner. “Just in general, we’ve had so much support from the Niles community, but I know that there have been a lot of people anxiously awaiting the whiskey. I’m excited to see that it’s finally available.”

The bourbon whiskey’s release is the first in a now-continuing series of single-barrel whiskey releases that Tuthill expects will occur every one to two months.

Before, the distillery only made and sold vodkas, rums, cream liqueurs, organgecellos and limoncellos. Rye, two-grain and three-grain whiskeys are on the horizon, each aged in a single barrel for months after being distilled next to Iron Shoe’s bar and eating area at 3 N. Third St., Niles.

For now, customers can purchase Tuthill’s bourbon in bottle form for $48 or through an Old Fashioned or Manhattan — that is, if Iron Shoe did not sell out of its bourbon by time of publishing. Tuthill expected it to.

The bourbon contains corn, barley, rye and chocolate malt. It aged in a 30-gallon tank for one year, Tuthill said, gaining the charred barrel’s vanilla- and caramel-like flavoring and its wood’s brown tone.

Once water was added to cut down on the bourbon’s alcohol by volume to 40 percent, 43 gallons of bourbon was ultimately created. That is about 3,670 standard drinks of 1.5 ounces, although most of the bourbon was bottled for sale, not for in-house drinks.

Tuthill said craft distillations like his bourbon whiskey offer a unique experience for customers.

“From me, you’re never going to get this flavor profile of whiskey again,” he said. “I may make the same Nashville (the same recipe), but there’s so many variables going into it. With it only being a single barrel, the chances are this exact flavor profile will never be the same.”

Ingredients, barrel surface area and aging time are all variables that could make his next single batch of bourbon entirely different, he said.

This method differs from big brands of whiskey, such as Jack Daniels, Maker’s Mark and Knob Creek. These brands want to keep their flavor consistent, Tuthill said, so they mix the contents of multiple barrels aging at once to create a close flavor each time.

Tuthill’s next release is a three-grain malt coming in late winter or early spring. He is also looking forward to a collaborative whiskey with the incoming Niles Brewing Company.