Chef Neil Perry commented: "No words xx".
"So so sorry for your loss. Sending you all my love and support in this difficult time," French-born chef Guillaume Brahimi said.
Fellow chef Kylie Kwong wrote: "Your beautiful, special, darling Sassy-girl … I am just so, so sad for all of you, I loved Sassy so much and hold you all very, very closely in my heart XXX."
Saskia Beer, the eldest of Maggie's two daughters, married Petar Jercic in April last year in South Australia's Barossa Valley.
"Thank you to everyone that made our country wedding beautiful, and to all those that sent their best wishes," they said in a post on Instagram at the time.
Mr Jercic shared a similar post to Maggie's tonight on his farmer, chef and caterer wife's page, Saskia Beer Farm Produce.
"It is with broken hearts we need to let you all know that Saskia, our beautiful, extraordinary daughter, sister, wife and mother died unexpectedly yet peacefully in her sleep on Friday night. The business Saskia grew and loved will continue on with me, her loving husband," Mr Jercic wrote.
"We ask for time and space as we grapple to come to terms with our loss and appreciate all the support we have been given."
The quality produce sourcing business was established in 1997, with Saskia "employing knowledge gained from her parents" Maggie and Colin, and carrying on her family's tradition.
"Saskia Beer grew up surrounded by the principles of good farming and honest cooking through mother Maggie's restaurant, The Pheasant Farm, and father Colin's game bird farming," her website states.
A post on the Adelaide Showground Farmers Market Facebook page on Sunday night read: "Vale dear Saskia".
"We have lost a dear member of our market, we must sadly share the news that Saskia Beer passed away unexpectedly but peacefully in her sleep on Friday," the post reads.
"The whole market community will miss her and we send our love and sympathy to her husband, children, parents and sister at this dreadful time.
"We know our market members and stallholders will do everything they can to support her husband Petar and the team at Saskia Beer Farm Produce as they try to imagine a future without their visionary founder."
Saskia is survived by her husband Petar, her three children, her sister Elli and their parents.
