MICHAEL KLEIN / STAFF

Vietnamese lotus root salad at Hello Vietnam.

Tri Tan lost her kitchen this summer with the closing of Nam Son Bakery in Ho Bin Plaza at 16th Street and Washington Avenue. One door closed, and another opened over the weekend in Northern Liberties with the debut of Hello Vietnam, a spare but comfy BYOB across from Green Eggs (722 N. Second St., 215-922-2800).

This time, chef Tan — who spent seven years there after decades at Nam Phuong — is an owner with daughter Julie Dinh and two business partners. Tony Ta, a former chef at Morimoto, Sky Asian Bistro, and Smith & Wollensky, is running the day-to-day.

First off, you’ll notice that the menu is not a phone book — just a half-dozen or so appetizers including rolls, glazed short rib, and fried tofu; a lotus root salad; pho; banh mi; broken rice platters; and vermicelli bowls, including Obama bun cha, which includes Hanoi-style meatballs. (This is what Barack Obama and Anthony Bourdain shared on a trip to Vietnam.)

Pay close attention to the tofu banh mi. Tan’s sauce makes the sandwich — and there are plans to bottle it.

Overall, you’ll notice clean flavors (nongreasy spring rolls, crispy vegetables, etc.), and the partners insist there’s something in the water. Specifically, they’re using a Kangen water-ionizing system that supposedly removes impurities not only from the ingredients and meats but also the drinking water.

722 N 2nd St Philadelphia, PA -19123 Northern Liberties-