Summer wine drinking should be easy - nothing too complex or heavy or expensive in hot weather.

Therefore, picking a wine should be easy, too. But it's not. From bottled sangria and kir through jug wines to sparking rose, the options are many and competition is fierce. Labels don't tell the whole story, so the only substitutes for guesswork are advice from the wine merchant or evaluation through tasting.

These approaches were combined recently in hopes of finding wines to moisten what may be a hot and dry summer.

The results were disappointing and left some doubts as to how useful expert advice is at the lower end of the price scale. Knowing the price range but not the names of the wines, the majority of a panel of tasters assembled by The Washington Post voted to buy only five of the 18 wines. Eleven were rejected, two of them unanimously. Feelings were ambiva lent about three.

This doesn't mean local wine salesmen have not tasting ability. There are stores without wine knowledgeable clerks, but in others the wine personnel are excellent and some are superb. Nonetheless, with the enormous stock and quick turnover in this city's leading wine shops, it is virtually impossible for them to taste every wine that passes through, so they probably cannot personally endorse every wine they sell. Also, the salesman is very price conscious. If he has found a wine of pedigree he can offer at an attractive price, he sees it as a good value - whether or not the wine in the bottle lives up to its reputation.

Here is how the tasting was organized: The guidance of a wine expert was requested specifically in nine local shops. Each was asked to recommend two wines of quality for backyard or picnic drinking. The only stipulation was that they not cost more than $3 per bottle.

Of the 18 bottles suggested, half fell into the dry white category. Another five were German, wines that traditionally are light and fruity (somewhat sweet). Three were red and only one was a rose, although these pink wines are often associated with outdoor dining in warm weather. Only eight of the 18 were the maximum cost, $2.99. But none was less than $2.29.

Somehow the so-called rules about matching wines with food don't survive the transition from the soft candlelight sun of the dinner table into the bright sun of the out-of-doors. Like picnic food, summer wines should not be too complex or ambitious. Generally one of two will do at any gathering. Few persons have the will or the desire to concentrate on tasting. There are too many distractions.

Consider young, light, dry red wines of any nationality. Contrary to superstition, red wines such as these benefit from being chilled somewhat, especially when nature's outdoor "room" temperature is in the 80s or 90s. Beaujolais was the red picnic wine before it became so full, so high in alcohol, so expensive.

Once out of the jug category, Bardolino or Valpolicello can be a good choice, or try a zinfandel of the light style, or a Bordeaux regional blend. Whites from Eastern Europe and German or California rieslings tend to be less dry - and perhaps more pleasant for drinking without a meal - than chardonnays from Burgundy or California. Rose has been wronged, dismissed completely by snobs and with some justification by those who have become impatient at tasting so much alcholic, flat sugar water. A fresh, well-balanced rose is a good choice for outdoor drinking. The French make a few and there are worthy examples from New York and Washington states as well as California.

"Why do you have to take a cheap wine to a picnic?" asked one of the tasters during the course of Teh Post's tasting. "I like picnics." Yet even accounting for inflation, $3 is not an inconsiderable price to pay for a bottle of wine. The purchaser is unfair to expect a wine in the $2 to $3 range to provide the same sensory stimulations as a great wine, but it should have distinctive characteristics and it should look and taste crisp and clean. In short, it should be well made.

Off odors or color, tastes of chemicals or unripe grapes are not to be excused. Beware, as well, of excessive age. If there is a vintage date on the bottle, check it as carefully as the price tag. Most of the world's wine is drunk less than a year after it is produced. Only a few wines, made ferm-aristocratic grape types, improve with age.

No one quality is indispensable in a summer wine. Wine glasses aren't essential for drinking it. But if heading for the countryside or boarding a boat don't forget a corkscrew.

The tasting results are in the accompaning box. The wines were tasted "blind" in the groupings indicated. The point scale would award 20 to a "perfect" wine.