The couple - the Earl and Countess of Strathearn when in Scotland - sipped a cask-strength single malt at Glenturret distillery near Crieff as they carried out a series of engagements.
They were given a tour of the country's oldest working distillery before bottling their own Glenturret whisky.
They tried the cask strength (57 per cent abv) malt, with William admitting it had "a bit of a kick to it" and Kate declaring it "delicious".
It was the couple's first joint engagement since their tour of Australia and New Zealand last month and their first official visit to Scotland, where they studied at St Andrews University.
They were greeted by crowds of hundreds of excited locals, including many schoolchildren waving Saltires and Union flags.
The royals opened the new-look Famous Grouse Experience visitor attraction. Established as a single malt distillery in 1775, Glenturret is also blended with other grains and malt whiskies to create The Famous Grouse.
General manager Stuart Cassells said: "It has been a real privilege to have them here. They said they liked whisky, both Prince William and Kate. Kate said William drinks more than her and does seem to prefer more peaty whisky.
"We were quite surprised at how many different whiskies they tried. Everybody in the team has been incredibly excited to have them here."
Kate also tried the Queen Mother's favourite tipple, gin. She approached David Lang, from Strathearn Distillery, to sample a heather rose gin. He said: "She came over and said 'Oh, I see you have some gins here. I shouldn't really try it because I had some whisky at lunchtime, but I'm going to.' She said it was absolutely delicious. I think she's a fan."