To some, a good whisky can taste like honey and spice with a hint of smoky peat.
Yet others can taste like battery acid mixed with ash from the fireplace.
Why?
It is one of many questions which will be answered at this year's New Zealand International Science Festival (July 5-13) in Dunedin.
Meenan Wines and Spirits Ltd managing director John Eckhoff will give whisky enthusiasts a chance to learn about the science behind the taste and smell.
''The science is connected to why whiskies taste the way they do.
''It comes down to what the French would call `terroir'. It's a term they relate to wines.
''Even though they are made the same way, they can taste completely different.''
The diversity of taste and smell came from the water and type of barley used; how it was malted and kiln dried; the shape and size of the still; the ageing process; the size of the barrel it was processed in; the type of wood the barrel was made from; and what the wood was used for previously.
The science festival tasting session would be accompanied with food made by Otago Polytechnic students.
Food was an important part of the tasting process because it ''switches on receptors in the brain and helps you taste the whisky'', Mr Eckhoff said.
The tasting evening will be one of many events held during the festival, which include expos, stunts, street science, debates, interactive demonstrations and inspiring workshops with world leaders in science innovation.
New Zealand International Science Festival associate director Rieke Lamb said the exciting programme aimed to show why science mattered - from the everyday to the big questions.
''As well as being a science festival, it is a playground.
''Science is amazing. You don't have to exclude anything; you can go in any direction - everything in our lives has a link to science.''
Festival director Chris Green said the catchphrase for this year's festival was to ''leave boring behind''.
''We have always been about showing why science is great, why it matters and why it is fun.
''But this year, more than ever, boring is out, and exciting interactive events which showcase discovery, creativity and the really cool places science can take you are in.''
