Nicholas and Mika Repenning, owners of go-en fermented foods in Whitefield, Maine. Credit: Courtesy of Chip Dillon / Blue Horse Photography

Miso is a fermented paste made from soybeans that serves as a staple of Japanese cuisine. With the rise of the foodie movement as well as health food advocates, the demand for miso has been on the rise in Maine.

One company has brought the time-honored process to the Pine Tree State, while some restaurants and other culinary experimenters have started dabbling in miso-making as well.

Mika and Nicholas Repenning started go-en fermented foods in Whitefield in 2015. The couple met while volunteering in Japan, where Mika is from, through the Worldwide Opportunities on Organic Farms (WWOOF) program in 2009. They had originally planned to live together in Japan, but their plans were derailed by the catastrophic earthquake, tsunami and Fukushima nuclear power plant explosion in 2011.

Instead, the couple moved to Maine in 2011, where Nicholas had family and had lived before volunteering in Japan. Mika liked Maine, but she was craving the flavors that made her feel at home — particularly miso.

“I couldn’t find authentic Japanese miso around,” Mika Repenning said. “It’s different from miso from the supermarket.”

The Repennings had some miso-making experience when they were working in Japan, so they decided to start making their own. The process of making miso starts with growing the koji fungus, which is also used to make soy sauce, sake and mirin.

Equipment used to make miso at go-en fermented foods in Whitefield. Credit: Courtesy of Chip Dillon / Blue Horse Photography

“That’s a process similar to growing mushrooms where we’re actually growing a culture on rice,” Nicholas Repenning explained. “When you’re talking Japanese flavor, it comes from koji, pretty much.”

The koji spores — which the Repennings order from a place in Japan that has been growing koji for centuries — are then added to the steamed grains. The whole process only takes a few days, but it is intensive.

“Initially, the koji needs to be kept warm [but] after it starts to grow it starts producing its own heat, and then it’s a process of keeping it cool so it doesn’t kill itself,” Nicholas Repenning explained. “We start with a big bundle of steamed grain, and then after about 24 hours or so that gets split up into wooden trays so I can disperse the mass into [smaller] amounts. Trays are stacked and that stacking order changes, check them every four to six hours. There’s one day a week I don’t sleep when we’re making koji.”

The equipment was somewhat difficult to acquire in Maine as well. When they started, the Repennings had to mostly make their own equipment, but they were able to piggyback off of some existing businesses in the state, like the now-closed Kittery brewery Blue Current that used to make sake.

“They showed me how they grow koji, they showed me how they do it at scale,” Nicholas Repenning said. “UMaine Orono actually created their steamer. I had the university duplicate those at a different size for me.”

Unlike traditional miso trays, which are made of red cedar, the Repenning made theirs out of white cedar, which was more readily available.

Equipment used to make miso at go-en fermented foods in Whitefield. Credit: Courtesy of Chip Dillon / Blue Horse Photography

“White cedar here is a really spiritual tree and using that wood kind of connects us to this place as well,” Nicholas Repenning said. “Its ability to maintain moisture and to have moisture come in and out of it without rotting is pretty essential because we are growing culture in these trays. We’re creating the perfect environment to grow mold so I need to be careful that I’m growing the mold that I want.”

Then, the koji-fied grains are added to cooked soybeans and left to ferment. They leave the barrel for a year at room temperature for a year and then harvest the miso — which Nicholas Repenning said raises the eyebrows of some food safety professionals at the state level — and then harvest the miso.

Starting go-en

The Repennings made miso for a few years for themselves, their friends and their community. Then, they saw an opportunity. They started selling their product at the local farmers market but soon demand was outpacing their homemade supply. Aside from Mainers who have visited Japan and seek out its unique flavors and foods — of which Nicholas Repenning said there are, in his experience, “more than you would think” — fermented foods like miso are popular in the health and macrobiotic communities.

“A lot of people’s doctors have told them they need to eat fermented foods, [so they] see our sign that the farmers market and say, ‘My doctor said I need to eat that, what is that?’” Nicholas Repenning said. “Once people figured out who we were, it wasn’t really hard to sell the product.”

There are other miso makers in the Northeast, but the Repennings saw an opening in Maine.

Miso from go-en fermented foods in Whitefield. Credit: Courtesy of Chip Dillon / Blue Horse Photography

“The commercially available stuff that you can get in packs are pasteurized,” Nicholas Repenning said. “Ours is not pasteurized [and] fits in the market you would see at a natural food store. The difference is a lot of those companies were looking to create a health food and we went for something that was more of an authentic Japanese taste. We can focus a little more on the intricacies of it.”

In 2015, they founded go-en fermented foods to spread the joy of artisan-made miso beyond their family and community. There are some challenges to making miso stateside, though, especially from a food safety perspective, despite the fact that miso has been healthily eaten for centuries abroad.

“I work in a gray area a little bit,” Nicholas Repenning said. “The food safety understanding of fermented products is complicated across the board federally as well as within the state. We’re working with living foods, and as long as these foods stay alive, they’re going to be safe, but we need to explain that to people. It doesn’t fit within the paradigm of food safety.”

Nicholas Repenning said that he has become something of an expert in food safety, taking a variety of classes and workshops to make his product as Food and Drug Administration-friendly as possible.

“A decade ago I didn’t even think I’d be doing this,” Nicholas Repenning said. “I’m a glass blower. Now I’m super nerdy about fermentation in general.”

Plus, he said that Maine’s food safety professionals have been willing to work with him throughout the process.

“The Department of Agriculture in Maine has been really supportive and they really want to see people survive at what they’re doing because that’s what Maine is,” Nicholas Repenning said. “I wouldn’t want to live anywhere else in New England.”

However, there are other factors about Maine that make the miso-making process challenging, like the environment and availability of raw materials for miso.

Mika Repenning preparing miso. Credit: Courtesy of Chip Dillon / Blue Horse Photography

“We get our soybeans from New England but specifically in Maine, it’s not particularly the climate for that bean,” Nicholas Repenning said. “We have a few varieties that we grow ourselves for small batches. There are people growing rice in Maine but the scale of production isn’t big enough or cost effective enough for us to maintain.”

The Repennings want to expand because they even have demand from out of state at this point, but there are things to consider, like the need for staff.

“When you scale up anything you lose pieces,” Nicholas Repenning said. “We want to do that without sacrificing the quality. If we were going to scale this up to a sustainable level it would involve bringing more people into the operation.”

Other miso makers

Currently, the Reppenings have the Maine miso-making scene pretty much dominated, but there are other people in the food space who have been experimenting with homemade miso.

Mike Wiley, chef and partner at Big Tree Hospitality, which owns Eventide Oyster Co., the Honey Paw and Hugo’s in Portland, said that he has experimented with house-made miso at some of his restaurants. He made miso for a collaborative dinner Hugo’s held with the restaurant Izakaya Minato.

“We made a special miso for that dinner, but it’s something that we’re not set up to do nose to tail,” Wiley said. “It’s one offs and we make some and we use it for a special. We’ve always been really excited at the prospect of trying to make everything from scratch, aside from Heinz 47 ketchup — don’t mess with ketchup.”

Wiley said that the process of making miso is challenging and might not be suitable for restaurants to do themselves.

“It’s a finicky process and cleanliness is absolutely paramount,” Wiley said. “I think it would be akin to like sourcing our own dairy, pasteurizing your own cream in order to make your own ice cream that you’re serving at your restaurant for dessert. It’s an impractical way to arrive at a product that you can buy and is totally delicious.”

Wiley said that maintaining the right moisture is probably the most challenging element.

“You want to cook the soy beans so that they’re just cooked,” he explained. “You don’t want them blown up. If there’s too much moisture in the system you end up inviting lactic fermentation [and] it’s going to go from sour to soured to spoiled to rotten and poisonous.”

Wiley sees the potential for miso in the Maine food scene, though.

“I love it,” Wiley said. “The miso world is as deep as the European cheese world. There’s so much out there. To build it into what we’re doing day to day, that would be step one to approaching the bubble.”

He thinks that foodies should experiment with miso if they are interested.

“It’s not as scary as it might sound,” Wiley said. “I would encourage people who are a little curious to do a little searching around, get some koji spores [and] give it a whirl. Our first whack at it I wasn’t totally blown away but the more we’ve done it the more we’ve learned. Families in Japan will make their own batch of miso every year. Not everyone in Japan is an expert and they’re doing it.”

The Repennings also see potential for miso to expand in Maine.

“I think that right now that market is expanding quickly and I think we’ll see a lot more stuff coming up in the realm of fermented foods [in general, as well as] Japanese ferments and seasoning,” Nicholas Repenning said.

The Repennings have also hosted workshops to try to expand miso making in Maine. They have not hosted any in the last year due to the pandemic but are hoping to get back on teaching people to make it themselves.

“We really feel like other people should make their own miso and other fermented food in general,” Nicholas Repenning said. “Normally we just make miso with people and they take it home and they open it up a year later. It leaves them in this dark area where they have to figure it out. We want to make more community events; traditionally, that’s how it would have been done.”

Beyond teaching people about the incredible health and flavor properties of miso, the experience of making it together celebrates the ethos of miso itself.

“Making miso together with people in the community is very good to really express what miso is,” Mika Repenning said. “It’s like a community, all different kinds of bacteria in the microorganism. Each person has their own microbiome and [with] homemade miso, your own microbes go into it and make a really well-balanced community.”

Watch more: