Often considered vegetarian in Thai restaurants, fish sauce, oyster sauce, and shrimp paste readily feature in Thai cooking. Furthermore, even if you find a vegan restaurant that does not use shrimp paste and fish sauce, oyster sauce is still a strong possibility as many Thais consider it to be vegan.
So what are the options and how do you get around the issues?
Fish sauce, or nam plaa, is used with abandon in Thai cuisine. Luckily, since some of the country's cuisine is cooked quickly and often on the spot, it's easy to customise your meals by asking for condiments like fish sauce and oyster sauce to be left out of a dish.
But what about at home? The fermented umami punch of this ubiquitous ingredient helps to make Thai food taste, well, Thai. But of course it isn't suitable for vegans, so what are some cruelty-free alternatives?
Here is where I get on my soap box. If there’s one thing that angers me in Thai vegan cooking it’s the fish sauce substitutes that either exist pre-bottled or that vegan recipe authors create. They are as akin to fish sauce as water is to wine. A good vegan fish sauce is made from fermented soya beans and lots of salt. If there is sugar, vinegar, lime juice, chilli, or any bits floating around in a clear or pink-ish liquid then throw the bottle right into the pits of hell. If your recipe includes seaweed or any of the above ingredients, don’t bother. Fish sauce does not taste like any kind of seaweed.
I have found the odd few vegetarian fish sauce varieties that are suitable (the brands you will find are likely to be Vietnamese), but they aren't easy to come by. If you can’t find it, use a combination of light and dark soy sauce or all light soy sauce. Adding extra salt is also an option. Sometimes I add salt and a little bit of fermented white tofu for a hint of pungency.
There’s a running debate on whether or not oysters are vegan, which I won’t go into, but in Thailand oyster sauce is often considered fair game in veganism. A Thai friend pointed this out to me years ago, but it didn’t hit home until I was standing in the kitchen of one of my long time favourites in Chiang Mai, Pun Pun, to realise he was right. There are several vegan varieties, but take note if you’re ever in Thailand, even at a vegan restaurant, to specify no oyster sauce if it’s a concern.
There are many oyster sauce alternatives, which are gloopy in texture and usually made with mushrooms. If it isn’t labelled vegetarian oyster sauce, the bottle might be labelled as mushroom stir fry sauce. Use these interchangeably with oyster sauce.
That gorgeous curry stall with half a dozen varieties, including an all vegetable blend, is about as likely to be vegan as a bean is likely to transform into a bat. Shrimp paste (gapi) is a fragrant fermented mass used in most curry pastes and often added to various Thai dishes for a pungent and salty kick.
You might think it’s gross, but you’ve probably eaten it if you’ve ever ordered a Thai curry in a non vegetarian Thai restaurant. Always ask beforehand if the curry pastes are made with shrimp paste. Most people know to ask for no fish sauce, but shrimp paste is still likely to be lurking.
There are vegan alternatives, readily (ish) available in Thailand, made from fermented bean protein. They are not dissimilar to a dark miso. In my opinion, vegan shrimp pastes made in Thailand taste more similar to Korean doenjang than to any Japanese miso. Nevertheless, miso is a good substitution, or a combination of miso and fermented bean paste. Swapping shrimp paste out for doenjang or miso will mean you still achieve a tasty end result. Seek dark bean pastes, not white miso, from your local Asian grocer if you feel like you want to spend the time making your own curry pastes.