Judges have sniffed, swirled and sipped more than 100 of WA's finest olive oils for this year's Perth Royal Show.
WA Olive Council executive officer Pauline North said 18 judges sampled 125 oils from 71 producers at the weekend.
There were entries from regions as far apart as Geraldton, the South West, Mid West, Peel and the Great Southern.
The judges, including Marek Kwiecien-Fisher and Isabelle Okis, followed similar practices to wine tasters.
The oils were first subjected to chemical analysis to test levels of polyphenols, peroxide and free fatty acids at the Department of Primary Industry in NSW.
Mr Kwiecien-Fisher, who produces oil near Gingin, said judges looked for faults such as rancidness, mustiness and mould and then assessed bitterness and pungency.
Depending on the variety - delicate, medium or robust - a top oil could have bouquet notes such as cut grass, fresh-cut hay or morning dew.
"There could also be artichoke and herbaceous flavours on the palate," he said.
"You don't want any notes like peanut, which could mean it's rancid, wet dog or mushroom."
Mr Kwiecien-Fisher said some samples in the fruitier oils had strong tropical notes, such as passionfruit, melon and banana.
As in wine sampling, judges used a spittoon after the tastings.
The winners will be announced next month.