Twenty-eight-year-old Alex Irvine is pasteurising and bottling A2 milk from his family's farm and delivering it to the door, just like his grandfather did.
"He was a milkman back in the day, delivering raw milk before milk was pasteurised and then he went into dairy farming."
The milkman wasn't in such great demand once supermarkets were authorised to act as milk vendors in 1987, but now the service is making a steady comeback.
Alex's company, Canterbury's Choice, started delivering fresh milk in reusable glass bottles in 2019, to customers in Christchurch and as far a field as Nelson.
"Back then I was doing the pasteurising, the bottle washing, the filling, the deliveries, so yeah, I was doing some pretty big hours."
Now Irvine has several staff and, as well as delivering more than 2000 bottles of milk a day to homes, he's also locked in some big commercial customers.
Canterbury's Choice beat out Synlait for the contract to supply milk to Canterbury University.
"Ultimately, the sustainability side of it pulled it through for us and we've got other places, like the Convention Centre and the Lyttelton Port, that go through a lot of volume."
Some of his business customers receive their milk in 10-litre steel kegs.
"So they'll hook it onto a small fridge and then just like you see down in the pub, you've got a tap and you can fill your milk up."
The Irvine family own four dairy farms, three in Springston and one in Leeston.
The cows that provide the A2 milk live on the first farm Alex's father, David, purchased in 1984.
"The three other dairy farms have got A2 cows in them but we filtered all the A1 protein cows out and put them at the other farms, so we could have 100 percent A2 milk."
A2 milk is a type of milk that has one protein different from the conventional A1 form, which may help some people who have trouble digesting cow's milk.
As Alex has mentioned, sustainability and environmental stewardship is a big focus on all the farms, that are home to about 3500 cows.
Chicken litter and mushroom compost are replacing chemical fertilisers to feed the soil and about 15,000 native plants have been planted in partnership with the Department of Conservation (DOC).
"We've also got a bioreactor in one of our waterways and we're pretty proud that, as dairy farmers, we can say that the water quality entering our property is dirtier than when it leaves our property and there are not many people who can say that," Alex says proudly.
The 150-metre strip uses woodchips to filter out nitrates from the water. The project was another on-farm partnership with DOC.
"We do different trials for them and Lincoln University to help out and it gets us to be at the forefront of the industry with the new technology that's happening."
Alex's father has taken a step back from day-to-day farming due to health reasons.
David had some initial reservations about his son's plans but he says he and his wife Carey are proud of what their son has achieved.
"We thought - a university graduate having his dream. Let's support him as you do for your children, but we didn't actually envisage what it was going to grow into and we're really impressed and really proud of what he's done."