Feast. Green Curry with shrimp.
I always have to remember that green curries are not forest-green, but rather a yellowish-olive green, due to the coriander, jalapeños and kaffir lime leaves that all contribute to the final color. The yellow hue comes from the addition of lemongrass and galangal. In any case, the green curry here was flavorful. The ratio of warming components (jalapeño, galangal, onion) to cooling components (lime, coconut milk, lemongrass) was perfect; the right ratio layers the flavors nicely, whereas the wrong amount lands you hankering for something more authentic.
It wasn’t until I tried making green curry myself that I noticed that true green curries request the use of galangal. It’s visually and physically similar to ginger, but the taste profile is vastly different; in my opinion, subbing them in authentic Thai dishes would be a cultural crime. (I’m not a recipe Nazi, but achieving “the right taste” is paramount in precision cooking).
In some circles, ginger is an acceptable substitution, under the pretense that your dish would not be the same.
Galangal, on many accounts, is said to be more “woody, piney, and medicinal tasting” than ginger. Some even experience it in the opposite direction as “delicate, fruity, and cooling.”
This paper has found that “galangal extracts exhibited strong superoxide anion scavenging activity, iron (2+) chelating activity, and reducing power in a concentration-dependent manner.” (In layman’s terms; respectively, neutralizing free radicals as found in lipid membranes, recycling and neutralizing reduced iron, and acting as an electron-donor).
Bottom line: Ginger isn’t a replacement for galangal and vice versa. Galangal is kind of expensive, at “four to eight dollars per pound.” But it’s worth it. It confers a specific, special kind of taste to authentic Thai dishes. It’s got a host of natural benefits when steeped or eaten in its raw form.