For many families, alcohol is an integral part of life, especially in the biting winters, and a variety of local liquors thrive in Nepal's markets along with foreign beers, whiskeys and wines.
Thapa says he first tasted raksi - Nepal's strong-smelling local brew with a kick - at the age of 10. Since then, he has acquired familiarity with the different concoctions brewed by different communities, each with its unique flavour, ingredients and way of drinking.
In the 1970s, he went to Britain to study about birds, where he was introduced to wine and took an immediate interest in the new variety. He learnt the art of making wine and came back home with several ideas fermenting in his mind.
The final catalyst was pheni, the local hooch of Goa in India, a hit with locals and tourists alike.
An inspired Thapa decided that he too would make a wine with local ingredients and came up with the idea of using herbs.
He uses 15-16 kinds of herbs along with curd, ginger, honey and other ingredients to make his novel wine, Thapa told Kantipur daily. The herbs are brought from northern districts like Mustang and Manag, close to the Tibet border. Thapa says he doesn't use any chemicals.
There are nearly 1.5 million bottles of "Hill Hot" available in four flavours, ready to hit the market.
However, there's one fly in the concoction. He is yet to get a licence from the government.
Last year, he told the daily, he had repeatedly asked the government of King Gyanendra for permission to sell his product in Pokhara. But there was no response.
With unsold bottles bottling up an investment of almost NRS 15 million (about $20,000), Thapa is increasingly worried by the delay.
However, there's one silver lining.
He remembers how he was once offered a wine by an acquaintance in Kathmandu and was overwhelmed by the taste.
His friend told him the reason. "It's a 13-year-old vintage. With wines, the taste improves with age."
Hopefully, the licence delay will give an improved tang to the stock sitting in his warehouse.