HERE'S THE dirty little secret about craft brewing:

Even though there are hundreds of world-class bottles available at the local distributor - beautifully made ales and lagers, beers that stretch the imagination with all kinds of unusual ingredients - you can still make your own just as well, if not better, and certainly cheaper.

Gone are the days when beer drinkers only turned to homebrewing as a desperate alternative to a pitiful selection of bland industrial American lagers. Today's homebrewer is more likely to have already sampled the new breed of exotic ales and discovered how to make his own knockoffs.

"Homebrewers are out there drinking as much commercial beer as they can. That's where they're finding their inspiration," said George Hummel, who runs Center City's Home Sweet Homebrew shop. "Then they just go home and figure out how to make their own version."

Homebrewing is hotter than ever. Hummel and other area shop owners say sales of both starter kits for newcomers and ingredients are up. The American Homebrewers Association says the hobby has been growing recently and estimates there are more than 500,000 homebrewers nationwide.

It's a trend that hop heads and yeast-pitchers will celebrate tomorrow with National Homebrew Day. Local shops and clubs will participate in a nationwide Big Brew, a daylong beer-making event in which scores of homebrewers will gather to simultaneously cook up tasty batches.

"It's a big party," said Jason Harris, who runs Keystone Homebrew Supply in Montgomeryville and Bethlehem. "It gives enthusiasts a chance to check out each other's systems. And newcomers get a chance to learn how to brew for the first time."

Harris and Hummel agree that the hobby increasingly attracts do-it-yourselfers who believe they can do it better.

"They're people who say, 'Yes, I can make beer and my beer is very good,' " said Harris. "Sure, they can go out and buy a perfectly good ale, but it's not quite the same thing as whipping out your own great beer."

Said Hummel: "People realize how much they enjoy the art of making their own, to have the hands on. It's all about the enjoyment of something that you made as opposed to something you select at a store."

But can you really make a beer that's as good as, say, Victory HopDevil or Rogue Shakespeare Stout?

As a guy who's sloshed his way through many, many beer festivals, I've gotta tell you that almost always, some of the most interesting, well-made beers are the ones they're pouring at the local homebrewers' table.

At the tasting hosted by Michael Jackson in March at the University of Pennsylvania Museum of Archaeology and Anthropology, for example, I heard the highest raves not for the microbrews and specialty imports, but for a Delaware homebrewer named John Greer, who knocked the socks off with his homemade imperial India pale ale.

Meanwhile, South Jersey's Bob Grossman, one of the area's most accomplished homebrewers, wowed everyone with his Belgian versions of barleywine and stout, as Hummel chimed in with something called multigrain Irish breakfast stout.

Yes, it takes time till you're winning medals.

But thanks to high-quality ingredients, including specialty grains, you can quickly mimic the best.

"Homebrewers are always interested in cutting-edge stuff, the latest hops or whatever Vinne Cilurzo [the guru at California's trend-setting Russian River Brewing] is doing," Harris said.

Lately, there's been much commotion over yeast, of all things - it's making homebrewers positively bubbly. (I suppose it goes without saying, there's a certain wild-eyed nerd factor in homebrewing. Don't let that scare you. Just learn how to pronounce "Brettanomyces" and you'll be safe.)

Suppliers have broadened their variety of strains, offering some that promise to duplicate the world's great brands, from Sierra Nevada Pale Ale to Westmalle Trappist Dubbel. Increasingly, homebrewers are experimenting with so-called "wild" strains that create complex, funky, soured flavors.

One yeast provider, responding to the trend, recently released a trio of strains that can mimic the tartness of Rodenbach, the sour aroma of Kasteel or the herbal richness of Saison Dupont.

Here's the kicker. Any one of those fine Belgian ales is going to cost you $80-$120 for a case. Do it yourself and you might spend less than $40.

And you can call it your own.

DIY

Want to make your own world-class beer?

You'll need a starter kit, consisting of large, reusable plastic tubs, tubing and other items, plus bottles and caps. The whole thing will cost you less than $100 for your first 5-gallon batch, including ingredients.

Many recipes are available on the Web.

The bible of homebrewing is "The Complete Joy of Homebrewing," by Charlie Papazian. Other recommended sources: "Extreme Brewing," by Sam Calagione, and "How to Brew," by John J. Palmer. Zymurgy magazine is an essential.

Check out the Big Brew tomorrow at Keystone Homebrew, 779 Bethlehem Pike, Montgomeryville, from 8:30 a.m. to 4 p.m. Info: 215-885-0100.

Hummel will run a homebrew demonstration tomorrow at the Old Eagle Tavern, 177 Markle St., Manayunk, starting at 1 p.m. Info: 215-483-5535. *

"Joe Sixpack" by Don Russell appears weekly in Big Fat Friday. For more on the beer scene in Philly and beyond, visit www.JoeSixpack.net. Send e-mail to joesixpack@phillynews.com.