Did you know that Fish Sauce can be a little like wine or olive oil? Yes, the vats used to age the fish sauce matters. The vats act like “oak to wine” and impart a special flavour. Premium fish sauce is defined by numbers that look much like the following: 40, 30, 20 and 15°N/L. The darkest-colored bottle is labeled 40°N/L and comes from the first extraction of liquid. The higher the number, the greater the concentration of fish protein. This combination give Red Boat that elusive fifth umami flavour. Although it's more expensive you use less as it's more flavoursome and concentrated. Use the Fish Sauce this is approved by Whole30 and used by favourite Paleo Community chefs like Melissa Joulwan, Michelle Tam and Tom Denham.