He started by saying "taste a carrot" and on stage he sliced some bright yellow and red carrots, piled them on a plate and passed them round the room.
Then he apologised that they had been out of the ground about four days and were not quite as good as they had been three days ago.
There are few chefs as dedicated to and passionate about vegetables as Schwass.
I remember the Savour volunteer who picked me up from the airport telling me about the chef who had brought his own carrots and other vegetables with him, and now I understood.
These were not just any carrots, but heirloom varieties grown by Schwass' gardener.
He believes, given the opportunity to taste a well-flavoured carrot fresh out of the ground and one that's travelled miles and been sitting on a supermarket shelf for ages, people can appreciate the flavour of the good, fresh one.
It took the Christchurch chef 12 years to cultivate a relationship with his gardener, whose name he wouldn't reveal.
His gardener is his inspiration, he said, "If you think I'm passionate about it, you should talk to him. He motivates me. He inspires the menu and drives the restaurant."
Schwass, who captained the gold medal-winning New Zealand Culinary team of 2004, started his own restaurant, Restaurant Schwass, in Ferry Rd, Christchurch, about six months ago.
His philosophy is to source the best products from local producers and use only what's fresh and in season, whether it's lamb from a local farm, fish landed nearby, or tomatoes and carrots from the garden.
His original inspiration came from the farmers' markets he bought produce from while working in the US and Australia.
Now, he and his gardener select the vegetables from a seed catalogue, the gardener grows them and when they are ready he sends them to the restaurant.
"Sometimes we don't know what's coming, but once we get everything, that's when we decide how we are going to cook it. Rather than writing a menu and recipes, we are very much inspired by what's around and the philosophy of not wasting anything."
With the price of food going up, especially when it's wrapped, packaged and often shipped halfway round the world, it makes sense to buy locally and not waste anything, he says.
He wants his food to be unpretentious and approachable, not elitist. He likes rustic cooking - slow braises and lots of root vegetables, but he serves them artistically in a modern style.
Needless to say, the menus change every day and the recipes he submitted to Savour New Zealand four months earlier were not those he cooked at his demonstration.
He cooked a leek and potato soup, but he used purple urenika potatoes and baby leeks, and made a stock by quickly cooking the potato peelings, green leek tops and a couple of fresh bay leaves in water, sweating the finely sliced leeks and diced potatoes in butter, adding the strained stock and cooking briefly, seasoning with salt and pepper and lemon juice, then pouring the hot soup over raw New Brighton crabmeat.
One of his signatures is to use several varieties of the same vegetable in one dish, and he revelled in the different colours of his beetroot - deep red, golden, and the remarkable red and white striped choggia.
He made a deep red purée with the red beetroot, a golden salsa with the golden beetroot, and served them with some fresh Nelson goats' cheese and toasted Canterbury hazelnuts, seasoned with local olive oil, salt and pepper, and decorated with thin slices of the red and white striped choggia beetroot.
