The sensory profile of a cup of coffee varies according to a number of factors including: the type and blend of coffee beans; geographical source; roasting method, and method of preparation. The variation in these aspects will impact the overall sensory experience obtained from a cup of coffee during both the preparation and consumption of the coffee. Specific aroma and flavour profiles are described by sensory experts to differentiate different types of coffees and roasts. Aroma and taste are the overriding factors determining coffee preference. Coffee aroma descriptors include flowery, nutty, smoky, and herby, while taste descriptors include acidity, bitterness, sweetness, saltiness and sourness see Coffee Flavour Wheel. The level of roasting impacts aroma profiles. Research has suggested that lighter roasts preserve the herb and fruit notes, whilst smoky and burnt aromas are increased, and acidity reduced, in darker roasts. A study has suggested that the release of saliva can affect the aroma experience, with results differing according to brewing method. In addition, it has been suggested that larger sips of coffee appear to generate a stronger release of aroma.