Fermented herring, or surströmming, has a strong, pungent smell that is often described as sour and fishy. The smell is a result of the fermentation process, during which the fish’s proteins break down and release a range of odorous compounds. The aroma of surströmming can be quite overpowering and may not be to everyone’s taste. Some people find it to be a fishy, briny smell, while others describe it as sour or fermented. The intensity of the smell can vary depending on the length of the fermentation process and the type of herring used.
It is important to note that the smell of surströmming can be released when the can is opened, so it is important to do so carefully in a well-ventilated area. Rinsing the fish in cold water before serving it can also help to reduce the intensity of the smell.