Transforming Flow into Flour

Like most migrants, our earliest colonial settlers missed familiar foods from home, and in addition, New Zealand’s native food sources were often difficult to procure in edible form. Dairy and meat supplies were relatively straightforward to establish, but staples such as bread proved more difficult.
In 1813, Northland Chief Ruatara became the first Maori to cultivate wheat, which was ground using a hand-mill provided by Reverend Samuel Marsden. Hand mills were portable but broke easily, and were often thrown away rather than being repaired.

Mill at Pipiriki

Mill at Pipiriki

Mechanised flourmills quickly became the most widespread industry in New Zealand, and remained one of the largest local industries throughout the 19th century. Wanganui’s first wheat was grown by William Bell in Wanganui East in 1844, and the first local flourmill was built by Tom Higgie at Putiki in 1845. By the late 1800s, a further five mills had been built at Pipiriki, Matahiwi, Jerusalem, Koriniti, and Kaiwhaiki. They were among the earliest mills in operation in the country. A millstone from the Jerusalem mill is currently on display at the museum.

Kawana Mill, probably early 1900s

Kawana Mill, probably early 1900s

Kawana Mill, near Matahiwi, is the only one of these mills remaining. It is also the oldest water-powered flourmill still in existence in New Zealand. Kawana Mill – full name Kawana Kerei Mill – was named for Governor George Grey who donated the millstones as a personal gift to the Nga Poutama people. There was also a Kawana Kerei Mill at Pamangungu near Rotorua, although like most early mills this one has not survived.

 

The Matahiwi mill was built in 1854 by millwright Peter McWilliam using salvaged totara logs, millstones from Australia, and machinery and bearings from England. Canoes were used to transport the heavy millstones upriver. In contrast, stones for a mill at Waitotara had to be rolled from Wanganui by hand.
Richard Pestall from France was Kawana’s first miller. His son continued to operate the mill after his father’s death until the mill closed in 1900 and was abandoned in 1913. The mill has a 5 metre iron-and-timber high-breast wheel, with water supplied at above axle height. Overshot wheels (where water falls from above the wheel) are more efficient, but they are also more difficult and expensive to construct.

Kawana waterwheel prior to repair in the 1970s

Kawana waterwheel prior to repair in the 1970s

The 1.2 metre diameter millstones are made from quartz pieces fixed together with a cementing compound (the French traditionally used plaster of Paris), and trimmed to interlock and work as a single stone of even quality. They are bound with an iron hoop around the outer edge.
The bedstone is fixed with a flat but grooved upper surface, while the runner stone above it has a concave lower surface and rotates via a central shaft geared to the waterwheel outside. The bedstone’s dressings are carved in ‘French burr’ (cheese segment) fashion and allow flour to flow via centrifugal force from the central eye where grain is fed from the hopper above, out to the stones’ skirt and through a chute to a sack below.

Dresser at Kawana with internal rotating brushes for grading the flour

Dresser at Kawana with internal rotating brushes for grading the flour

Stones are ‘dressed’ using a small pick to ensure grooves remain clean. Blunt or clogged stones produce poor-quality flour – and can cause machinery to jam. The stones are housed in a wooden tun, with a wood-framed ‘horse’ above to support the feed hopper. Wooden cogs in the cast iron wheel reduce operational noise, and a leather strap across bottom of the hopper rang a bell to alert the miller when grain ran low.

 

 
After grinding, flour was cooled before being returned to the upper floor for grading using a wire mesh cylinder with waterwheel-driven internal brushes. Kawana Mill had three dressers positioned one above the other – Grade 1 flour was collected from lowest level.
The waterwheel and millstones at Kawana are authentic, but the mill building is a replica designed by architect Chris Cochran and opened by Governor-General Sir Keith Holyoake, in October 1980.

 

Article by Karen Wrigglesworth, local engineer and writer.

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