Burgers with a conscience

When it comes to fast food, hamburgers have always been the show dogs of the genre. They strut their meaty stuff while fans debate each patty's traits as carefully as if they were judging champion hounds at Westminster. Shape and size, tenderness and juiciness, char, and cut of meat are just the start of it. And now, there's one more criteria to add in: How eco-friendly is it? That's right, soon the question won't be just how pink your burger is, but how green.

In May, Grille Zone fired up its energy-efficient grill and opened its doors near Boston University. If all they did was churn out their oh-so-juicy all-Hereford chuck-and-sirloin burgers, they'd already deserve a mention. But the Zone goes the extra earth-friendly mile. Everything about this casual, self-service burger joint is eco-conscious.

All their major equipment is energy efficient. The cheery décor is mostly recycled, and the bulk of their ingredients are locally sourced. Meanwhile, all their paper and "plastic" products are biodegradable. So, it may look like you're using a typical plastic cup, paper plate, or throw-away spoon, but it's really a corn starch or sugar cane-based material that will decay within 90 days to garden-worthy compost.

Char-grilled, cooked-to-order, and dripping with juices, the burgers are a half-pound medium-thick patty with good sirloin flavor served on a fabulously light, crusty, toasted Portuguese roll ($5.95). In short, a flavorful burger on a substantial bun.

Fixing's are kept to the classics: lettuce, tomato, onion, etc., just like the menu, which features only eight items. Co-owner Ben Prentice explains they wanted "a laser-focused menu, where choices are limited but each item is superb." To create it, he and his college buddy and co-owner Barry Baker spent more than a year obsessively taste-testing ingredients.

In other words, these two avowed foodies are making fast-food with a gourmet attitude, and you can tell. Fries were fresh cut, skin-on delights ($1.95 /$2.95) that were crisp-edged, soft-centered, and not at all greasy. In a word: flawless.

The house-made vegan burger ($6.25) was surprisingly flavorful, if somewhat mushy, and unlike the usual bready patties, it was brimming with fresh vegetables you could actually see and taste.

A grown-up grilled-cheese sandwich ($3.95) came with gooey aged cheddar oozing out from between thick, tasty slices of grilled farm bread, and the juicy beef-and-pork hotdog ($4.50) made by Smokehouse in Mattapan was just as good. Thick-as-knockwurst, not too salty, mildly smoky, and with a good snap, it's likely to make a few favorite lists.

But the chicken breast sandwich ($6.50), a menu item I've come to dread, deserves the blue ribbon. All too often, dry meat and dull buns make this "healthy alternative" about as tasty as eating a foam shoulder pad. But here the never-frozen meat was moist, piquantly seasoned, gently charred, and served on that same hotshot Portuguese roll.

Buffalo wings ($7.25) suffered from water-logged celery and carrots, but drinks and dessert had no faults. Our Herrell's ice cream chocolate frappe ($3.95) was rich and creamy, and a lime Rickey and squeezed-to-order lemonade ($2.95 each) were refreshingly tart and not too sweet.

When we were done, everything, from our straws to our ketchup cups, went in the compost bin, which makes the location fitting. It's on the Green Line.

(Correction: Due to a reporting error, the size and price of Grille Zone's burger was incorrect in the Aug. 9 Cheap Eats review. The burger is a half-pound burger for $5.95.)