At a riverside bar just outside Bangkok, a delicious revolution is underway.

Every Saturday, Chit Beer microbrewery opens for beer lovers and those who want to learn the craft of craft beer.

"It's getting very very popular now because when people know more about the concept, that yeah, we can make beer ourself at home, [they're] excited," said Wichit Saiklao, better known as Chit.

But these weekly classes are an act of rebellion.

Home-brewing is illegal in Thailand.

To get a beer-making licence, Thais must be able to produce 100,000 litres a year and have $400,000 in the bank, which effectively shuts out small players.

The 1950 Liquors Act also protects the two giant conglomerates that dominate the cheap lager market — ThaiBev with its Chang (and the infamous "changover"), and Boon Rawd Brewery's Singha and Leo beer.

Thai craft brewers are forced to take their recipes to breweries overseas and then import their bottles back into Thailand, paying hefty tax.

Most brew in Asia, but not all.

Home brewing is illegal in Thailand. ( ABC News: Liam Cochrane )

Phuket's Full Moon Breweries makes its fruity Chalawan Pale Ale in New South Wales and the logo for its Chatri IPA is a Muay Thai fighter with a koala head.

Melbourne's Red Dot Brewery produces oddball flavours from the Lamzing brewery, including Sticky Mango (pale ale), If You Like Pinacolada (saison), Morning in Monsoon (stout).

But the "imported" Thai beer is sold at premium prices.

So for the maverick of Thailand's rebel brew scene, defying the law is not just about tasty beverages, but freedom and self-sufficiency.

"When people feel they are empowered to do something, to rely on oneself, then I think many many good things will come after we can make beer ourselves at home," Chit said.

"That's my vision."

Chit's Beer overlooks a river in Koh Kret. ( ABC News: Liam Cochrane )

Don't be lonely, brew beer

Chit's "vision" started with two flops.

Thailand's evangelist of ales first tasted craft beer while studying in the United States.

He put the idea in the back of his mind, thinking it would be a good hobby later in life.

"I'm afraid I'm going to feel lonely, so if I can brew beer then friends are going to come over," he laughed.

"If they're having a party they remember that they have to invite Chit [because] Chit makes beer."

But five years ago, he decided retirement was too long to wait, and ordered a do-it-yourself kit on the internet.

His first two batches failed because he threw out the yeast, thinking the small packet was a deodorizer.

But the third batch was a success and sparked a passion that has proved contagious.

Thais must have $400,000 in the bank to get a beer-making licence. ( ABC News: Liam Cochrane )

When your drinkers are actually undercover cops

By mid-afternoon, the bar is packed.

While most punters sample the small-batch offerings on tap and watch the river pass from the sunny deck, a small group huddles around Chit taking notes, measuring out grain and asking questions.

"I didn't realise how many types of ingredients there are to make beer," said Dominic, a Bangkok resident from the United Kingdom.

"I've just tasted the first batch and it tastes amazing."

Chit Beer is located on the island of Koh Kret, about 20 kilometres north of Bangkok.

The classes are kept low key, but Chit has had his run-ins with the law, after undercover officers carried out a particularly thorough investigation.

"They drank a lot of my beer and played around in my brewery but I don't know who they are," he recalled.

"Then two weeks later they showed up with a badge and they know everything about me."

The risks are starting to pay off.

The scene is growing in Bangkok, with dedicated bars and the Craft Space Beer Week currently underway in Bangkok.

Chit hopes that if enough people start brewing at home, the law will have to change.

"We can have more power, more voice and I think this place plays a role to expand, to create the voice," he said.