Tua Nao: The centuries-old Thai condiment you need to try

A plant-based shrimp paste alternative from Northern Thailand

Tua Nao, which roughly translates to “rotten beans” are fermented soybean cakes that have been used as a seasoning in the north of Thailand, and Laos, for hundreds of years.

They’re made from cooked soybeans pounded into a paste and left to ferment for several days. They have a strong flavor similar to shrimp paste and have traditionally been used to add a sense of umami to otherwise simple dishes.

  • Tua Nao Kep (dry) — the cakes are pressed into disks and sun-dried.

Tua Nao has a distinctive, toasty and nutty smell and delivers a big hit of umami in whatever it’s added to — similar to shrimp paste.

The north of Thailand is an interesting melting pot of cultures and influences from the neighboring countries of Myanmar (Burma), China (Yunnan), and Laos.

Tua Nao has traditionally been used as a flavor enhancer, long before shrimp paste (Gapi) was prevalent in the north. For many people in the north, meat was scarce while growing up. Some ate it as little as once a year for Buddhist ceremonies or other special occasions, so Tua Nao was used to add bold flavor and umami to otherwise simple dishes.

“In the old days, people would grill those [Tua Nao] and crumble them over rice and I think that was pretty much what a meal was for some people, 80 or 90 years ago” — Austin Bush

These days, Tua Nao is treated much more like a seasoning, and you wouldn’t struggle to find it with chili, salt, and sometimes lemongrass.

Boil, mash, ferment, repeat

Making Tua Nao is simple and the majority of the process — cooking, fermenting, and drying — is passive. Including drying, it takes about a week.

The paste starting it’s 3–5 day fermentation journey | Credit: Alex Heery

You can even split the batch and ferment the two differently for some A/B testing.

Ferment your beans, or paste, in a well-sealed (and cleaned) vessel for 3–5 days, until there is a slightly sweet aroma with a noticeable hint of ammonia.

“If you drive around Mae Hong Son in the morning or the evening, you’ll definitely smell it. It’s still a fundemental part of the cuisine there.” — Austin Bush

My first attempt was a little rough — the disks didn’t quite work, so I ended up with chips.

The case for bad beans

Few names are as uninviting as “rotten beans,” but given the little effort required and return on flavor, it’s hard to look past Tua Nao.

So by fermenting soybeans, we’re producing a flavor that hints at the complexity of shrimp paste.

It’s worth noting that many dishes that call for Tua Nao also have shrimp paste, and some would argue that Tua Nao is not a reliable substitute — and maybe they’re right.

Cook and food writer based in Mexico City. Talking food and all its intersections | IG: https://instagram.com/_alexheery

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