"We sold our stock online and couldn't believe the response. Because they're rare, they're only going to become even more sought after," Mr Phelps said.
"I'm chuffed we've reached the semifinals of the Steak of Origin ... these are great lifestyle block animals and their meat is brilliant. It's well marbled, tender and full of flavour. When you taste it you know it's something special, it's 'wow'."
Despite having full time jobs - Mrs Phelps is a teacher at Weber School and her husband runs his own business in Dannevirke - the couple are determined to boost the breed in New Zealand.
"Currently our Hinterwalds are 7/8ths pure-bred, the highest in New Zealand and we have to be very selective," Mr Phelps said.
The couple were drawn to the breed because they can cope with hilly ground and are good at foraging for grass. "They're easy to manage," Mr Phelps said.
And with the farmlet run on organic principles, although not organically certified, the herd grazes on pastures of herbal lay, including chicory, tonic plantain and lucerne.
"Our neighbours look over the fence and think the animals look good, considering they're in a weed paddock," he said.
"Our animals have never seen a chemical drench or antibiotic. We buy in non organic hay because there's a huge cost for the organic variety, but we've only had the vet out once in the eight years we've been here and our calving rate is 100 per cent," Mr Phelps said.
The couple receive a good price for their stock's meat, sold mainly to friends, well above the beef schedule, Mrs Phelps said.
"Our friends get very good quality meat at a price much less than what they would spend on mince," she said.
With faith in their breed and the knowledge a Hinterwald beast took out last year's supreme Steak of Origin award, the Phelps are quietly confident they will be in the finals.
Their animal, 18-month steer Pierre was fed well, but received no special treatment and is definitely no "designer" cow, Mrs Phelps said.
"We're just interested in rare breeds. Our chickens and turkeys are all rare breeds too," she said.
The semifinalist steaks have all been through rigorous scientific testing at Carne Technologies and tomorrow a panel of judges, comprising chefs and food writers will make the difficult choice of deciding which 20 beef sirloin steaks will go through to the grand final at the Beef Expo in Feilding next month.