John and his partner Louise Strong have begun selling Baba's Relish at Kaitaia's Saturday market, and, if it's as popular as they hope it will be, they plan to ship consignments to John's daughters, Camryn and Cailie, who are establishing careers in Wellington and Auckland respectively, in the hope that they will be able to sell it at their local markets to help pay their eye-watering rents.
It will also remind them of their great-grandmother.
"It's hard for me, and no doubt even harder for my daughters, to imagine what life must have been like back then," he said.
"My grandmother couldn't go to school because she had to cook for the gumdiggers. These days kids don't even have to make their own lunches."
He had been enjoying the relish all his life, he added, thanks to his parents, Ian and Helen (the main cook in the family) Stewart, who had been faithfully following Ian's mother's recipe for years. John started making it this year, and didn't find it easy to adapt the recipe from family-sized baches to 120 jars at a time using a commercial kitchen, but he cracked it.
His handful of tomato plants at Waipapakauri Ramp were never going to produce the 45kg he needed per bach, however, so Walter Masters has provided the main ingredient.
What else, apart from tomato, was in there he wasn't saying - "Just call me the Colonel," he said - but he knew he had got it right when he began hearing people comment on the home-made texture that stood it apart from all and any opposition. Not that 96-year-old Maria Stewart had tried it.
She now lives in a rest home in Auckland, and whatever accolades Baba's Relish receives, they won't match John's pleasure in seeing her smile when he gave her a jar.
"She was so proud to see her face in the label. I will never forget that," he said.
"She hasn't opened the jar yet, but I suppose she doesn't have to. She knows exactly what's inside it."