NEW YORK ( TheStreet) -- There's no doubt the U.S. service economy -- especially bartenders, waiters and waitresses, hairstylists and other "hands-on" service professionals -- can be sensitive, and even hostile, toward bad tippers. Otherwise, websites such as LousyTippers.com wouldn't exist. The website takes no prisoners in outing consumers who throw nickels around like manhole covers. If you undertip or, worse, don't tip at all, there's a decent chance your name will wind up on it. As the website says to its audience of service professionals who rely on gratuities for a living, "If you provide this service and get nothing in return, usually all you can do is complain to your co-workers. Now you can complain to the world and expose those who take advantage of your hard work." Fair enough, but fresh data out on who tips well and why suggests alcohol is a prime motivator for a more generous gratuity. That isn't to suggest non-restaurant service professionals such as hairstylists and massage therapists should begin plying their clients with wine, beer and spirits (although nobody is saying it isn't worth a try). But if you really want that big tip, priming the gratuity pump with alcoholic beverages is the way to go. At least, that's the sentiment from Restaurant Sciences, a Newton, Mass.-based restaurant industry analysis firm. The firm studied 4 million guest checks at dining establishments across the U.S. from February to November and ranked generous tippers in its Hey Big Spender survey. In it, Restaurant Services analysts conclude that, on average, beer, wine and spirits imbibers tipped just over 20%. Digging deeper, waiters, waitresses and bartenders may want to really start making sure the wine list is the first thing customers see after settling into their seats. The survey says the average check for wine tipplers was $69.05, well beyond the $38.74 for beer drinkers and still well ahead of the $55.19 accumulated by spirits drinkers. That would seem to make tipping a clear "volume issue," Restaurant Sciences says. But hold on, bar and restaurant professionals. If you dig even deeper, you can earn more cash by focusing on specific adult beverages. For example, the best tippers, according to the survey, were bourbon drinkers, followed by blended whiskey drinkers, cider, gin and vodka. Somewhat surprisingly, cordial drinkers, who usually stick around for that extra cocktail after dinner, are the cheapest tippers, followed by rum and scotch drinkers. "Guest checks with only wine sales are 25% higher than checks with only spirit sales and 78% higher than those checks with only beer sales," explains Chuck Ellis, president of Restaurant Sciences. "Whether consumers ordered beers, wine or spirits, they generally tipped an above-average amount of more than 20% per check." Maybe a looser persona also tends to loosen the wallet and pocketbook. Or maybe consumers who indulge in a few cocktails are more generous customers. Either way, the path to fatter tips for restaurant professionals isn't on the platter. It's behind the bar.