WHEN THE subject is barbecue, the rabble is rife with opinion. Be it ribs or minced pork, barbecue arouses the passions. It incites, like chili, perhaps, great and eternal food debates.

A passing comment can become a mild discussion; mild discussions escalate to enraged discourses. Friendships and marriages are imperiled. Such are the powers of ribs.

Everyone, it seems, can tell you where to get the best barbecue . . . even if it is half a continent away. But too often that leaves the question still burning closer to home.

As many Americans will celebrate the Fourth of July with some kind of barbecue, eight tasters, seized by patriotism and civic spirit, bravely set to a blind sampling of 37 versions of the sacred sauced pig.

The ground rules were fairly simple. Ribs and/or minced pork were picked up from 23 restaurants and carryouts. We aimed for lunchtime, but some leeway was demanded because the geographic area ranged from Charles County in the south to Gaithersburg in the north in Maryland; all over the District; and Alexandria, Fairfax and McLean in Virginia. Represented were nine places in the District; seven in Virginia; and seven in Maryland--an even but not all-inclusive sampling.

The foods had to be available for carryout but we made no special requests, except to order ribs and minced pork when available. Not everyone included sauce separately.

The tasters were greeted with an awesome assortment: slabs of ribs, sandwiches of every description, containers of minced pork, bright sauces, accompaniments of bread, vegetables, french fries. And napkins, many napkins.

The assembled ribs--all marked by numbers only--were rated as to meatiness, texture, flavor and seasonings; the sauces and the minced pork were judged separately. Each entry was also given a final rating on a scale of 1 to 10.

When all the sauce had settled, the results held only a few surprises for local barbecue aficionados.

The best and the worst were relatively easy to describe. But most fell into the middle--not great, not awful--and were hard to differentiate. Many would make a good meal. Rib It sent beef ribs instead of pork but several tasters liked them equally. And, in fact, despite a couple of entries that elicited "I love it" and "I hate it" simultaneously, both the range of opinion and the gap between most liked and least were not extensive. What did become obvious was that the group divided sharply on the questions of soft versus chewy ribs and sweet versus spicy sauces. Many tasters also had various physical reactions that suggested that a considerable quantity of MSG is involved in some of these recipes.

Penny's in Charles County, Maryland, placed first. Second place was a three-way tie among Randy's and Johnny Boy's (both also in Charles County) and Bare Bones in Gaithersburg. There was also a tie for fifth place between Scott's and Thrifty Carryout in the District.

These results prompt one to wonder about southern Maryland's secret. And open pit could be it.

Open pit cooking usually refers to an outdoor structure of cement block or fire brick with a grill area over an open wood fire. Although most area jurisdictions either prohibit or closely regulate such cooking techniques, Charles County, at least in some instances, does allow them.

The District and Arlington, Alexandria and Fairfax in Virginia allow open pit cooking in such short-term situations as carnivals, fairs or church events. And several jurisdictions mentioned that there are commercial-grade indoor smokers that, with proper hoods and vents, meet local regulations.

In Arlington, Glen Rutherford of the Environmental Health Department said that the two major considerations in open pit cooking are how the food is protected from contamination and the safety of people around it. In Prince George's County there are no operating open pit restaurants but, according to Alan Taylor at the Directorate of Environmental Health, anyone who cares to meet the regulations is free to apply. He thought, however, that satisfying these conditions would be too costly to make it profitable.

Richard Helfrich of the Montgomery County Health Department said that they try to enforce regulations on both commercial and noncommercial concerns in an even-handed manner, but added that it was difficult.

The best barbecuers say their "secrets" start with using good quality meat and end with good secret sauces. But of course that's no secret at all. Pat Penny would be no more specific than to say that at Penny's, which has been in operation on and off for the last 25 years, "secret" seasonings go on top-quality meat that is smoked with hickory and oak and then sauced. At Randy's, Randy Keeton, and his father Don, emphasize the importance of not overcooking the ribs, but are equally vague describing their "secret" to success: quality meat, well cooked and well seasoned.

And at Bare Bones in Gaithersburg, where the ribs are seared and baked rather than smoked, Roger Reese reveals only that terrific sauce and, of course, a good grade of meat are the keys.

But at least one ribs purveyor feels that the real secret of barbecue goes beyond these basics. At Johnny Boy's, which got its start in 1966 in the District and then branched out into two locations in Charles County three years ago, owner John Katsouros said he agrees on the vital ingredients of quality meat and good sauce. But he believes the atmosphere and informality of the country and the aroma of the fire combine to evoke a mood that makes a trip to any of the several Charles County rib shacks an event in and of itself.

He may be on to something.