Introduction: Umami is a basic taste. However, practitioners often refer to it as a flavour, indicating that sensory interactions may affect the gustatory response. Dashi is a basic soup stock that can be made simply by extracting seaweed into water (Mouritsen, Williams, Bjerregaard, & Duelund, 2012). By creating a sensory diverse set of dashis, we can explore odour-induced umami enhancement by omitting the sense of smell in sensory characterization of the dashis. Methods: Dashis were made from 16 seaweeds (9 different species) collected from locations in 6 different countries, following procedures of Mouritsen et al. (2012). Samples were characterised by standard sensory descriptive analysis (with and without olfactory input), HPLC (Mouritsen, Duelund, Calleja, & Frøst, 2017) and GC (Juhari & Petersen, 2018). Results: Main effects of olfactory stimulation was found for the basic tastes umami (p=0.001), sweet (p=0.017), and the flavour roasted (p=0.01), with decreases in intensity when olfactory input is prevented. Similar effects were found for the aftertastes astringent, metallic and fatty. However, odour-induced enhancement, indicated by statistical interactions between olfactory input and samples was only seen for umami (p=0.018) and astringent (p=0.009). HPLC analysis demonstrated that three samples (table 1) with high umami intensity had very low glutamate content. Scrutinizing the aroma compound concentration by GC identifies a set of candidates that can have increased umami (table 1). Conclusions: Sensory interactions between basic tastes and aroma compounds were found in seaweed dashi. Odours that enhance umami were observed in three samples with very low glutamate content. A number of potential odour-induced umami enhancing aroma compounds is suggested (table 1). Odour-induced umami enhancement can be used to create more palatable foods with simple and sustainable means.