Just across the river from the old Grain Belt Brewery, Kevin Welch has wedged what he calls a glorified home-brew setup into a tiny warehouse space. His bottling equipment is still in his garage; he personally welded and retrofitted some of his tanks.

But this Chinese-speaking, concert French horn-playing brewer has a secret weapon to help him make waves in the ever-expanding Minneapolis beer scene. He’s culturing multiple strains of yeasts personally imported from breweries across Belgium.

The result is a quartet of traditional, bottle-conditioned, Belgian-style ales. Welch released his two core ales at Pig & Fiddle last Thursday, and as of this morning, it’s the only place with Boom Island Brewing on tap.

Silvius, a 5.5% ABV pale ale, delivers a crisp rush of apple and mild spice flavors. Malt and yeast mingle on the light finish, creating a clean, autumnal flavor where the hops take a backseat. Thoprock, on the other hand, is a burly, deep amber-colored IPA that smacks you right away with a distinctive hop and earthy spice flavor. A healthy dose of alcohol (it’s 8% ABV) rounds out its full-figured profile. Batches of a Dubbel and Tripel (named Hoodoo and Brimstone, respectively) are currently in the works.

Bottles of both Silvius and Thoprock will be available at Four Firkins on Monday, and more tap and retail accounts will be added shortly. We headed to Welch’s glorified home brew shack to learn more.

HEAVY TABLE: Tell us about the conception of Boom Island Brewing.

KEVIN WELCH: About five years ago we [Welch and his wife] lived in China and built a little one-and-a-half barrel home-brew setup. We traveled around, experimented with Tibetan spices and cool stuff. We came back and pursued the classical thing, playing with Minnesota Orchestra and St. Paul Chamber, while coming up with the plan for Boom Island. I’ve been a Belgian freak ever since I tried my first one, a Westmalle Tripel. We did two summers of travel around Belgium, visiting small family breweries, learning tricks and techniques.

HT: What is it about Belgian beers that really turned you on?

KW: I was a huge hophead, I mean, I still am. But when I had that first Tripel, it had all of these, what I learned later were, esters and great yeast flavors that come from the high fermentation temperature. I couldn’t put my finger on it at the time so I started studying them.

HT: You are, to my knowledge, one of the only commercial-scale breweries around here that cultures all of its own yeast.

KW: I have a good friend at the University of Minnesota who’s a microbiologist. He’s offered to take the slants and keep them under perfect laboratory conditions. I learned plating and slanting myself, and then I bounced a lot of ideas off of him.

HT: And how many unique strains do you have under culture?

KW: Thirteen. That was part of my trips, to go research which breweries were using which strains. It wasn’t always possible for me to grab some out of their primary fermenter, but when it was, I carried 25 autoclaved test tubes.

We were very happy to get them, including the one very special strain that you can’t get anywhere but at one monastery. That’s the secret for the Dubbel and Tripel. Without naming any specific names, that’s the special yeast. You can draw your own conclusions on where that is. [Editor’s note: It seems likely that the beer being alluded to here is the famous Westvleteren 12 of Belgium’s St. Sixtus Abbey.]

HT: Compared to the other brewery startups in town, your fermenters are tiny. You’re doing really small-batch stuff.

KW: On a weekly basis, we can do about 500 gallons running them simultaneously. But all the small batches will always go in this one – 100 gallon, two and a half barrels – that’s for the Thoprock, Dubbel, and Tripel. And those were intended to only be bottle-conditioned beers, but Mark [van Wie of Pig & Fiddle] was excited to get it going and asked for kegs of the two [Silvius and Thoprock]. The hoppy beer ended up selling better than the pale, so that’s when we decided to start doing big batches of Thoprock here and there to keg.

HT: How would you compare your IPA to everyone else’s around town?

KW: It’s hopped in a similar way, I don’t want to go completely in your face, which is more of a Belgian approach. The one notable difference is I do a candy sugar addition the same way I do the Dubbel. It brings the alcohol up to 8 percent. I heard a lot on Thursday, “This is great. I get the hops, and I don’t have to drink four of them.” It’s a Belgian way of getting the ABV up without thinning out the body.

And all the hops in the IPA through batch four will be grown right here in Minneapolis – Cascades and Centennials. I was talking to Omar [Ansari of Surly] and he said, “Really nice hop aroma on this. You mind me asking?” I said they’re Centennials. “I knew they were!” he said. “Where did you get them? Everyone’s sold out for the year!” Well, I grew them myself and for that aroma I’m going to stretch them as far as they can go.

HT: And what batch are you on now?

KW: Three. At some point I’m going to have to regroup and figure out the strategy like everyone else. I keep thinking I’m going to archive some of it, but hop aroma and flavor degrades by 50 percent over the course of a year. You have to drink hoppy beer fresh.

HT: Would you recommend laying down your Dubbel and Tripel when they come out?

KW: Yeah, those could lay down three years. The first few batches, we will archive those and release some as vintage.

HT: And you won’t be kegging them?

KW: The Dubbel and Tripel will only be bottle-conditioned and Four Firkins is likely the first place you’ll find them. But all the kegs are unfiltered too, which makes it living beer. In Belgium, it’s a big thing, if there’s not something in there growing, it’s not worth drinking.