He began to stop into Starbucks, and became friends with some baristas around Lakewood. Eventually, his barista network grew — “A bunch of my Facebook friends are Starbucks baristas,” he said — and now that network helps his Web site stay current.

Mr. Ort helpfully marks all Starbucks products with either a green light or a red light. The Frappuccinos all get red lights. The Tazo teas, green lights. Hot chocolate, green light — but white hot chocolate, red light. The Vivanno smoothie? It depends on the flavor. Mocha drizzle on top — yes! Caramel drizzle, no.

Yes to whipped cream.

Mr. Ort is not the only macher in this game. Rabbi Sholem Fishbane, the kosher supervisor for the Chicago Rabbinical Council, spent more than two years stopping into Starbucks stores all over the world, researching his definitive 2011 document, “Guide to Starbucks Beverages.” “I’d say I visited 50-plus Starbucks,” Rabbi Fishbane said, calling from his vacation house in the Catskills. “It’s safe to say I’ve been to three-quarters of the states. I’ve been to Japan.”

Rabbi Fishbane’s paper is a thorough, painstaking document. For example, he discusses at length the Starbucks dishwasher, which uses 180-degree water — a reassuringly sanitary temperature, but bad for Starbucks’s kosher status, because it is considered hot enough to absorb nonkosher flavors into a pot.

And he gives permissible ratios for nonkosher ingredients in a kosher food: “Even though it is possible that a tiny bit of nonkosher grease might be on the rag used to wipe the steamer wands and that grease might end up in my steamed milk, the milk remains kosher because the volume of the milk is more than 60 times the volume of the grease.”

Rabbi Fishbane is a full-time kosher supervisor, and his Starbucks visits were just side trips on his travels. Mr. Ort, by contrast, is part of the Starbucks community — and, he says, a more reliable guide than even some of the professionals.

“The large certifying agencies, such as the Star-K and the Chicago Rabbinical Council, are far too quick to simply say beverages in Starbucks are not kosher,” Mr. Ort said. They are thus “keeping themselves safe while inconveniencing thousands of people, when in fact, according to Jewish law, many beverages are completely kosher.”