Fans of prefab pina coladas can learn from reading the label that such a product contains nondairy creamer. But those who sip California wines will not learn without a special letter to the vintner that the product contains sulfur dioxide in addition to grapes and yeast. Even with a letter, the producer might not reveal total contents. They are not required by law to release that information.

The Center for Science in the Public Interest, a Washington-based group that watches technology and its relation to the food supply, has addressed the alcohol labeling issue for more than a decade. Concerned not only that the public has a right to know what's in food, but that some of its additives might indeed be harmful, CSPI is suing the government to require labeling of alcoholic beverages.

In a 10th-anniversary revision of its book, "Chemical Additives in Booze," CSPI chronicles the organization's fight with government and industry to require ingredient labeling on beer, wine and hard liquor. The book, says CSPI director Michael Jacobson, "gives the detailed story on how the alcohol industry and the Reagan administration have fought alcohol labeling."

Chemical additives in liquor present certain health hazards, Jacobson says. Many people are allergic to sulfur dioxide, a common additive in wines and beers; others report hives, headache and nausea. Yellow dye No. 5, which the FDA singles out for color labeling on food packages because it causes allergic reaction and which is present in liquor, is not required to be listed on liquor containers. Other federally approved additives have never gone through testing as components of alcoholic beverages, according to the book.

Worst of all, says Jacobson, were the deaths of several individuals in the 1960s, apparently from an overdose of an additive (cobalt sulfate) in beer. The book reports that had the victims' doctors known about the additive, they might have known to administer the antidote. (Cobalt sulfate is no longer added to beer.)

The Carter administration established liquor labeling regulations after conducting research to test consumer acceptance and industry costs. These regulations were scheduled to take effect on Jan. 1, 1983, and would have required the label to reveal additives, preservatives and enzymes or, at the very least, an address to which someone could write for that information.

The regulations were an early casualty of President Reagan's "regulatory relief" plan, however. According to a spokesman for the Treasury Department, under whose jurisdiction alcohol control falls, the department was "unable to conclude that the benefits to consumers of ingredient labeling for alcoholic beverages outweigh the costs that would be passed on to them. . ."

The book's appendix compiles the information presently available about the contents of alcoholic beverages supplied by manufacturers, labels and scientific tests.