Together with Chef Kornthanut Thongnum, Khon Kaen-native Thanaruek Laoraowirodge has brought his Isaan roots to the capital in the shape of this somtam-focused restaurant whose objective is to steer our taste buds back towards Northern Isaan, and away from the sweeter flavors that Bangkokians so cherish. The space isn’t going for the requisite grungy street vibe, though. On the contrary, Somtum Der’s got a little mezzanine which lets in plenty of light, ably supported by the white walls and lots of blonde wood. A red accent wall, the central somtam bar and craft-inspired bamboo lamps add warmth and Isaan flavor to the mix. The kitchen’s only compromise to Bangkokian’s weaker stomachs is to pasteurize the pla ra (fermented fish sauce). Apart from that, you can expect full, well-rounded heat in the dishes that call for it. Of the score of somtam varieties available, standouts include the tam sua Sakon Nakhon (B65), which comes with freshwater crab and kratin beans, and the tam pla tu khao man (B85), which comes with mackerel and is served with a comforting side of rice cooked in coconut milk. In very different ways, they’re both exemplary of what Thai food does best: balancing a range of flavors and textures. Of course, there’s also a long list of usual suspects, from laabs to tom saep, all equally well executed. We’re less impressed with the deep-fried or grilled meats. The fairly small portion of crying tiger beef (B95) is good but not great, while the deep-fried chicken (B75) would be somewhat flavorless if it wasn’t for its addictive dipping sauce. As for drinks, we’re happy to report they have Beer Lao dark (B95) and tasty martinis (B120) made by infusing vodka with lemongrass or rosella. Lunch sees neighboring office workers who don’t mind paying a little extra for somtam with air-con, while dinner draws a lot more tourists, alongside boys headed to Silom Soi 2. There’s this psychological price barrier that one must overcome when eating Isaan food in a nice setting—and despite Somtum Der’s fairly small plates, bills here are definitely not at street food levels. But compare this to other restaurants with a nice décor and polished service and this is one affordable, friendly and tasty place. Corkage B200.