It's Friday afternoon, the sky is blue. Some wine would be nice, but you can't afford an import and don't understand all those years and foreign names, anyway.

Gallo's Vin Rose is supposed to be inexpensive and good, but isn't it made with the blood and sweat of exploited migrant child-laborers? You want to be a good citizen, and even Walter Mondale supports the United Farm Workers, so you decide against buying a Gallo wine.

Some Boone's Farm instead? Maybe a bit more class with Andre Cold Duck? Ripple, Thunderbird, Madria Madria Sangria, Tyrolia, Carlo Rossi, Red Mountain or Josef Steuben?

If your liberal consciousness has been raised you check the label, see Modesto, California (most California wines don't list the winery or put a UFW seal of approval on the label), hurl the bottle at the wall and scream that Gallo cannot deveive those who are aware! All Modesto wines are produced at Ernest and Julio's family winery.

How do you explain your violent antipathy to the police? "Well, officer, in 1973 the Teamster goons came in and..."

Or maybe you quote, from a 1975 UFW advertisement headlined "There's blood on those grapes: This isn't a fight between two unions. It isn't even a fight between labor and management. We're fighting for our lives. Because we need our union to survive. And we think the Gallos and the other grape-growers are guilty of union-busting."

The officer still isn't convinced. He begins to jingle his handcuffs. You start to explain away your outburst, but you find you have to go back to the beginning of the story.

Gallo, the world's largest winery, produces one-third of all the wine sold in this country. Because the winery is privately owned it does not publish financial statements or release statistics, but a UFW source estimates that Gallo sells at least $250 million worth of wine and reaps profits of at least $35 million each year.

In 1967 the UFW organized the field workers and signed one of the nation's first union farm-workers contracts. That three-year contract was renewed in 1970. Even today, fewer than 50,000 of the country's 2.2 million agricultural workers are unionized.

In that 1975 advertisement urging consumers to boycott Gallo, the UFW said that they established "the beginnings of health and safety protection," prohibited the use of DDT and other possibly dangerous pesticides, prohibited the illegal hiring of children, got toilets and drinking water and washing facilities in the fields, and "stopped forced migrancy by introducing hiring halls and eliminating labor contractors" in the six years after they won their first labor contract in 1967. The implication is that they did all those things at Gallo.

But Solomon says Gallo had a medical plan for its workers for several years before the UFW came along, and that was the plan used between 1967 and 1969 until the UFW came up with their own. He adds that Gallo has never used labor contractors because they are a large enough company to run their own employment office.

"It's important to distinguish between Gallo and the other 62,000 growers in California," Dan Solomon, a Gallo spokesman, says. "There were problems with the labor contractors at other farms, but Gallo has never used them. If you want to talk about the Gallo boycott, you should talk about Gallo," he says.

Although the second contract expired in April 18, 1973, two persistent problems dragged the negotiations to a halt in June. Ernest Gallo said at the time that the "inefficiency" of the union hiring hall and problems with the UFW's methods of union discipline blocked the discussions. Solomon says the hiring hall was poorly run, adding that the union was having problems all over the state with their hiring halls.

Mark Johnson, the Boston UFW representative, says it is true there were problems with the unions' halls at first but they have been cleared up. For example, workers had to report to the hall daily and go to the fields from there. Now UFW members report directly to the fields.

Gallo spokesman Solomon says the union fined workers who refused to take time off from work to attend union meetings or picket other fields, and fined workers $5 for just missing a union meeting. "I don't think we've ever required workers to attend meetings. That's not our policy," Johnson says.