You can choose either mild or hot gochugaru. For some things I will use the less spicy flakes so I can use more, and make the dish redder!
“Maewoon gochugaru” means very hot spicy hot pepper flakes and “Deolmaewoon gochugaru” means milder hot pepper flakes. Try to buy the ones that are made with sun-dried peppers, which will be labeled as 태양초 on the package. After opening a bag flakes, keep it in the freezer to maintain its freshness.
Buying hot pepper flakes can be difficult if you don’t read Korean because many Korean manufacturers will mislabel the product in English. But take a look at the product in the package if at all possible. Hot pepper flakes are always coarse and chunky.
This one is tricky because in English it says “Red Pepper Powder,”and underneath that it says “Piment” which is French for “red pepper” or “spice,” and then there’s another label that reads “Coarse.” But this is really a bag of hot pepper flakes. You can tell by looking at the big flakes through the transparent part of package. Red pepper powder is something different. They’re a lot finer and mainly used for making gochujang, so you need to be careful of what you’re buying.