S.O.R.E.L. Learn 6 is an interactive flavour-chemistry learning and comparison tool designed to help flavourists understand how changes in molecular structure relate to changes in odour and flavour perception. Rather than simply looking up individual chemicals, the user can select matched pairs, isomers, chemical families, predefined teaching studies, or build a custom set by sensory category. The underlying approach is to compare molecules systematically—holding as much of the structure constant as possible while examining changes such as chain length, branching, functional group, substitution position, unsaturation, or stereochemistry. This follows the S.O.R.E.L. principle of moving from identity → structure → physical transport → sensory tendency, rather than assuming that one property such as functional group or boiling point determines smell.
The tool then turns those selections into a visual structure–sensory comparison. Molecules can be inspected in aligned interactive 3D views so the user can rotate, zoom, overlay and directly see which atoms, bonds or stereochemical features have changed. Alongside the structures, the tool compares chemical identity and physicochemical information with organoleptic observations, including primary and secondary odour descriptors, retronasal aroma, basic taste and trigeminal effects where data are available. This separation is important because what we commonly call “flavour” is a combination of several sensory routes: orthonasal smell, retronasal olfaction during eating or drinking, gustation and oral/trigeminal sensations.
Most importantly, S.O.R.E.L. is intended as a learning workbench rather than an automatic smell predictor. The user can explore questions such as What happens when an alcohol becomes an aldehyde?, How does moving a double bond change a green note?, Why can two positional isomers smell different?, or How does methyl substitution alter a pyrazine from roasted toward another sensory region? The system uses matched comparisons to develop a local structure–odour rule, while also showing its boundary, nearby exceptions and evidence strength. This reflects the underlying flavour-chemistry data, where structurally related families can show useful sensory tendencies but also substantial exceptions—for example across alcohols, aldehydes, esters, acids, ketones, anthranilates and other families.
