Greg Tselikis knows exactly what goes into making the Holy Trinity Greek Orthodox Church’s festival such a success every year.

There are 650 pounds of lamb, about 4,000 grape leaves, 550 chicken halves, 10,000 cookies and an uncountable number of pastries and glasses of wine.

He said organizers just take Greek music and sweet early summer weather and stir.

“We serve basically the same thing, year after year,” he said as a line with hundreds of people snaked down Pleasant Street in Portland and the festival kicked into high gear Friday night.

“This is the benefit of having been accepted by the community. We’ve become kind of like an institution.”

The numbers back him up. Although the organizers don’t keep track of attendance at the festival, which is free, they can back out numbers from the amount of food consumed and estimate that about 9,000 people attend most years underneath a huge white tent next to the church.

Tselikis, who was baptized in the church and is president of the parish – which means he also is in charge of the festival – said his role is to not tinker too much with success.

He said the festival has added a few more vegetarian options in recent years to accommodate changing tastes, but otherwise it’s not too much different from when it started 35 years ago: some good Greek food, Greek wine, Greek music and Greek dancing.

Most of the folks in charge of the cooking, he added, are of Irish ancestry.

“The ambiance is kind of fun,” Tselikis said, adding that the low-key approach is part of what draws people. Essentially, the festival celebrates Greek culture by encouraging people to come out and eat and maybe take a tour of the church, he said.

Among those attending this year was John S. Nuveen, who spent a couple of years as a child in Greece when his father was an ambassador-level U.S. representative during the postwar Marshall Plan rebuilding of Europe.

He said he’s attended the festival most years since it started except for a time when he lived in California.

On Friday, he came with a group from a senior community center in North Conway, New Hampshire, and said what he likes most is a lot of people enjoying a culture in which he feels deeply rooted, despite his Dutch ancestry.

“It’s like being in a parade without walking in it,” he said as he waited for a seat at one of the communal picnic tables to open up.

Jill Reynolds, a worker at the community center, said she’s been going to the festival for years with friends, and decided to organize a trip for the seniors who go to the community center.

“I decided to see if anybody else would be interested, and they sure were,” she said.

Shawn and Cheryl McKinnon of Falmouth said they stopped in at the festival last year and it quickly became a favorite.

“It’s good food and it’s different,” Shawn McKinnon said. “It’s just community.”

Tselikis said that’s the kind of reaction he and other organizers aim for. A committee of about 20, he said, works on tweaks over the winter between festivals, but they mostly try not to mess things up.

The goal is to get a lot of people together for meals and mingling.

“Just come and enjoy,” he said. “Your ethnicity is irrelevant.”

The festival concludes Saturday, when the hours are 11:30 a.m. to 9:30 p.m.