The art of seasoning
It was said that spices is the secret of Vietnamese cuisine. Food is always better when properly seasoned. Your foods will taste better, smell better once you've mastered the herb and spice basics. Let's start with some common elements.
Monosodium glutamate (MSG)
MSG is a widely-used flavour enhancer. But it may be harmful to your health if isn't used wisely. You shouldn't use MSG to marinate foods, nor putting it in while cooking on high heat, because this causes decomposition of toxic substances. A tip is only adding MSG when foods are done, or when the heat just went off.
Salt is the most essential spice for every dish. It makes foods taste stronger. The amount of salt you need depends on what meal you're preparing. For soup, it's better to wait until foods are stewed. But for caramelized fish and fried dish, salt should be added before you start cooking, to make sure the "sweetness"/ “natural fresh taste” of meat and fish remain. When you boil foods, it's ideal to add salt before vegetable and meat, when water is boiling. This helps to keep the vegetable green and the meat won't turn to brown.
Sugar is sweet, it helps your dish taste better. However, keep in mind that sugar is burn on high heat. If you add sugar when foods are almost ready, it takes time to melt and makes the disk sweeter than expected. For caramelized dishes, sugar needs to be added at the beginning to marinate foods. And it's OK to put more sugar latter on. Regarding soup and stir-fried dish, remember to add sugar after salt, to remain the foods' sweetness.
Vinegar is sour and it will destroy your dish if you put it in during the cooking. Depends on your dish, vinegar should be added before or after the cooking.
Peppers is aromatic and lightly spicy. Its aroma will lose over high temperature. Many people add peppers as a cooking habit, but it's not a good practice. A trick is to add peppers when the foods are cooked, or to sprinkle peppers on the surface of the dish for flavouring.
Fish sauce owns a distinct flavour, but it will be changed during the cooking. Thus, attention need to be paid on the point of time: put fish sauce in porridge, soup or stir-fried dish when the foods are done; add it in caramelized dish after other spiced added. Don't add fish sauce 30 minutes before cooking, otherwise it will ruin the taste.
Broth mix is a newly-manufactured seasoning that is commonly used these days. It's salty and has a "like-meat" taste. Add broth mix to marinate foods or during cooking. You shouldn't add broth mix when the foods are cooked because it cannot melt any more.