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Macadamia Processing

 

MacNut Farms is not just New Zealand’s largest macadamia orchard but also the largest macadamia processing facility. We process all our own orchard’s nuts as well as macadamias from many other orchards in the North Island. MacNut aims to be the processor of choice to NZ growers by offering an efficient and competitive service.The processing operation is broken into the stages detailed below:
Dehusking
Once the nuts are picked they are loaded into the hopper which feeds the dehusker (right). The dehusker has two rotating rollers which rip the tough outer husk from the nut. The brown nut that emerges has a moisture content of around 25% and weighs only about 46 % of the total. The huskings are composted and mixed with chicken litter to be used as fertiliser the following year. The hopper & dehusker
Drying
Macadamias hung out to dry To allow the nut to be cracked and the crunchy taste to develop they must be dried from 25% moisture after dehusking to 3% before cracking occurs. At MacNut this is a two stage process. First the nuts are stored in a green house, which allows moisture content to be reduced to less than 10%, then they are moved to a heated container with temperature between 40 – 50 deg C for a week to reduce the moisture to 3%. As you can see (above) we store our nuts in onion bags to allow airflow and easy handling. Each bag contains about 15 kg of nuts
Cracking

The nuts leave the dryer and are put in the cracker hopper. The cracker consists of rotating knives that crack the nuts in a wedge shape.

The loose kernel and the nutshells then enter the trommel (shown below). The trommel is a rotating sieve with holes that get larger along its length. Small pieces fall out at the start and larger pieces further on, with any uncracked nuts rolling out the end to be re-cracked with the next batch

Once the pieces have fallen through the holes in the trommel the shell is separated from the kernel using air blowers. As the nut and shell fall down air passes upwards. The lighter shell pieces are blown upwards into collection bins while the denser kernel falls onto the conveyor belt for hand sorting.The trommel in action

The waste shell makes a beautiful and unique driveway surface at the orchard – always a source of interest with visitors. The local birds have developed a taste for macadamia scraps left in the shells on the driveway. We sell shell in bags or in bulk by special request.

On average we recover about 30 % of the nut weight as kernel the remaining 70 % is shell and waste.

The cracker and sorting operation is run on average 6 hrs a day, 5 days a week and can process around 500 kg of kernel each day. At the end of each day the equipment is cleaned and disinfected. Over a whole year MacNut Farms processes around 100 tonnes of nut in shell.

Sorting, Cooking and Packaging

The hard work starts once the kernel arrives on the conveyor belt. Here our staff separate the kernel into different types (chips, halves, wholes) and sizes. They also discard any bad or immature kernel and shell pieces.

The kernel is sold as raw, roasted and salted, chocolate coated, manuka honey coated, or our special Kiwimac. (half macadamia and half kiwifruit in chocolate). The chocolate coating is done under contract for us and returned packaged.

Hand sorting macadamiasTake a tip from us and taste our special large wholes in chocolate.  Most manufacturers who buy from us ask for small whole kernel so they can give you minimum kernel and maximum chocolate (which is cheaper) –  we give real value with maximum nut and enough chocolate … taste the difference!!

Another favourite variety is the roasted and salted nut, which is cooked on site. The bulk raw nut is lightly cooked in coconut oil in 2kg batches for 3 minutes, sprinkled with salt and excess salt and oil rubbed off to give a crisp and full flavoured product.

Each type is packed in bulk bins or boxes for shipment to our wholesale clients.

For our retail foil packs we carefully weigh and nitrogen purge to give you a long shelf life whether it be raw, salted or chocolate coated.

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Macadamia Nut Growers’ Guide – MacNut Farms

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GROWING MACADAMIAS IN NZ… THE MACNUT GUIDE
  • Location
  • Varieties
  • Planting
  • Pruning
  • Weed & Pest Control
  • Fertiliser
  • Yields
  • When to Harvest
  • Husking
  • NIS Drying & Storage
  • Transport to Processor
We have written this to answer questions on the growing, harvesting and transport of macadamias in NZ.  We do not consider ourselves experts in this field, and you would be better to contact a consultant than ask us about specific problems.  The information contained is purely advice that has been compiled from our experience and documents written by others.  We accept no liability for the accuracy or results of application in your circumstances.Location

Macadamias require temperate to tropical climates that are frost-free.  Present experience suggests that plantings will be most successful in the Auckland and regions further North.Macadamias prefer soil rich in organic matter but can tolerate a wide range of conditions from clay to sandy loam.  Main requirements are good drainage, a pH balance of 5-6, plenty of light, protection from wind when young and average rainfall or irrigation if very dry.  Macadamias dislike frosts or sitting in pools of water but otherwise are very tough.Trace minerals such as magnesium sulphate, zinc, boron will help as will organic nitrogen.

Varieties

There are two main species of macadamia:

Macadamia tetraphylla comes from mid NSW and is more tolerant of cooler climates.  These trees tend to be vertical in growth and prickly with pink flowers and new growth.  Most rootstock is tetraphylla.

Macadamia integrifolia comes from Northern NSW and Queensland and prefers warmer climates, they are less prickly and rounder in shape.  The new growth is normally light green and flowers white.
Commercial varieties are inevitably hybrids, which show several of the characteristics of the above species.  In general NZ grows hybrids with tetraphylla characteristics.

Commercial macadamia trees are generally grafted from a good rootstock variety.

The main grafted varieties that have been planted in NZ are shown below.  These varieties have now been largely replaced by new and improved hybrids.  Advice should be sought from www.macnz.com for the latest types suitable for NZ’s cooler climate.

Beaumont
A good quality nut that does best on warm sites but is difficult to pollinate.  Must be handpicked and may have too much vegetative growth on cooler or fertile sites.

PA39
Matures early and tends to drop nuts, a tetraphylla like hybrid that crops well and combines well with Beaumont as a pollinator.  Easily infected with veggie bug.  May need pruning to remove denseness.

GT1
A good self or cross pollinator which can crop heavily with smaller nuts and may require extra feeding.  The tree is less dense and prone to wind damage.

Renown
An open tree with good crop and is a good pollinator.  A good variety for home use with large and at times irregular nuts.

Own Choice
Another good variety for the domestic garden with good self or cross pollination, large nuts and few prickles (Integrifolia characteristics).  Tends to crop inconsistently and year round which is not much use commercially!

Elimbah
Attractive tree with inconsistent crops and many pink flowers in season.

There are many more varieties about which specific advice can be sought from a nursery.

As ground collection is generally unsuitable for NZ’s wet condition trees with good cropping characteristics and suitable for hand picking are preferred in NZ.

No planting of a single variety is recommended as macadamias do better when the various types are mixed to allow cross-pollination, thus increasing yields.

Planting

Macadamias are best planted in spring.

Trees should be planted in rows with a 6m row spacing and minimum 4m spacing between trees allowing for ingress of light, air and insects for pollination and room to grow to maturity.

Young trees can be protected by shelter belts, which can be removed later.  Mature trees still require some protection due to their brittle nature but large shelter belts will effect light levels and a balance must be sought.

If dry months are predicted an irrigation system may be useful. Ensure the water is of hygienic quality.

Pruning

Some pruning is desirable after planting to reduce the tree to two leaders at each branching.

The tree should be manicured to allow for light, picking and air movement in the center.  The tree can be thinned to a minimum of internal branches without effecting production.  Height should be limited to picking height.  After pruning new growth may also need to be trimmed.

Weed & Pest Control

The main problem for NZ macadamias is the green vegetable bug, which can pierce the immature nut and stain the kernel brown, making it unsaleable.  We spray with Deltaphor 25 EC three times a season at intervals of three weeks, and 3 weeks after flowering (so pollination by bees is not affected).

After this period the nut should be hard enough to resist attack.  Towards the end of flowering (September) one preventative spray with Dipal for the Leaf Roller Caterpillar is advised.  Alternate measures for pest control include chickens or possibly wasps that will out-compete the veggie bug.

Where chemical control measures are undertaken ensure these measures are in compliance with health and safety regulations for application and the possibility of the retention of toxic residues.

Rats can be a problem and an eradication program is advised.  The rats often reside in bird’s nests or piles of rubbish or weeds and these should be removed.

Possums will eat soft greens nuts and goats the whole tree in early years (although goats prefer other trees to macadamias).

Trees should be kept clear of weeds using either a herbicide like ‘Roundup’, mowing or sheep.  (We use sheep, which do not disturb mature trees but are not good for ground harvesting)

Accurate records of pest and weed control measures will allow optimisation in future years.

Fertiliser

Annual leaf and soil analysis should show up deficiencies and point towards a fertiliser program.

Applications of trace elements can be achieved in airborne sprays.

In addition ground based applications of superphosphate or organic manure or mulch can provide valuable nutrients.  In particular a good source of mulch will be the prunings and husks from the nuts.

Avoid heavy application of nitrogen in summer as this can promote vegetative growth at the expense of nut quality and quantity.
Accurate records will help determine the effectiveness of any program.

Yields

Top orchards in NZ have returned yields of 4-6 tonnes per hectare.

To estimate the crop sizes for a well-tended orchard use the following as a guide:

Tree Age Kg per Tree
5 2
6 5
7 8
8 10
11 15
25 55
Orchards not achieving above 2 tonnes per hectare could have basic location or nutritional problems.  Specialist advice should be sought.When To HarvestMacadamias in NZ tend to hand picked due to wet soil conditions, so it is important to pick between when the nuts are ripe and when the nuts drop.Normally the nuts are ripe by June and this can be assessed by observing nuts dropping, splitting on the tree.  To test for maturity: when opened the nut husk interior and the nut should both be brown (not white).Nuts are picked by pulling or cutting the racemes from the tree and may be collected efficiently by placing nets under the tree.The harvest of immature nuts will result in many small and hard kernels which must be hand sorted out and reduce the value of the crop.Husking

Nuts should be husked within 24 hours of picking to prevent respiratory heat in storage, which can in turn increase mould, rancidity and germination.  If the nut cannot be husked immediately the nut in husk should be well ventilated and dry.
Rocks and debris of a large nature should be removed from nuts before husking.  Husking machinery should be checked to ensure that the nuts are not being cracked or bruised in the process.

NIS (Nut in Shell) Drying & Storage

Moisture after dehusking is normally around 25% and must be reduced to around 1.5% for cracking.  Nuts should be crisp when fully dry and will rattle when shaken to indicate that the kernel has shrunk away from the shell.

Nuts should be hung in a well-ventilated place to reduce moisture content before transport to the processor.  The minimum moisture content that can be achieved without commercial drying is around 10%.  Failure to store in a dry well ventilated pace will lead to mould, rancidity and germination.

Contamination or wetting of nuts in storage should be of highest concern with special attention paid to ensure that no condensation in the storage area or leakage from outside can occur.

Avoid prolonged exposure to direct sunlight, which can increase rancidity and cracking of the shell.

If using heating in the drying process do not use temperatures in excess of 38 deg C if the NIS moisture content is above 10% as this can create browning of the kernel.

Do not store nuts for prolonged periods at moisture contents greater than 10%.

Transport To Processor

Take precautions to ensure chemicals, foreign debris or manure during transport does not contaminate the nuts.  Cover the macadamias during transport to ensure the nuts arrive dry and clean.

Avoid drop heights greater than 2m as nuts may be cracked or bruised in handling.

Delivery to processing should be immediate after removal from well-ventilated dry storage.  Transport times greater than 24 hours can result in increases in rancidity and mould.

Ensure adequate information about type, time of picking and storage conditions is provided to the processor to allow optimum processing.  Label any nuts to identify ownership and date of transport.

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Cultivation of Macadamias

GROWING MACADAMIAS

Macadamias thrive in the following conditions:

  • High rainfall
  • Well drained soil
  • Warm and frost free climate
  • Some wind shelter

Macadamia trees are extremely tough – in fact they’re quite hard to kill. They produce economic quantities of fruit after 8 years, although fruit will be borne in small quantities as early as two years. Trees live for 70 years or more, reaching a height of 20 metres. At MacNut Farms we have the ingredients for a successful orchard, although a little more warm weather wouldn’t go astray.

The growing year at South Head is broken into the following phases:

Flowering and Pollination: OctoberThe trees flower during October with long white and pink racemes making this the best time of year to visit the orchard. At this time of the year the orchard is home to beehives to assist in pollination and ceases picking operations to minimise disturbance to the flowers. The Beaumont hybrid that dominates at MacNut Farms has been planted with other varieties to improve its poor self-pollination.
Pest Control and Weed Removal: late Spring to AutumnOver the warm summer months the picking is finalised and the trees are sprayed with liquid fertilisers and veggie bug control agents. At the same time the prolific growth of weeds is controlled by sheep and maintenance around the trees. Further fertilising with mulch from the husks, chicken litter and some chemical fertilisers is completed at this critical stage of growth as the new nuts set and grow on the trees. Macadamia trees are biennial, alternating heavy and light cropping years.

 

 

Picking, Pruning: Winter and Early SpringAt the start of June the picking season begins. Picking in NZ is done by hand as the Beaumont hybrid does not drop it’s nuts.  In Australia mechanical harvesting from the ground is the norm. The racemes of nuts are clipped from the trees and are collected in nets placed on the ground.
It is common practice to have a pruning gang working just in front of picking gangs. In this way access to the trees is improved and high branches can be cut and left on the ground for picking. Over the past two years we have pruned the orchard to allow better air flow for pollination, more light ingress, better access for picking and allowing the trees to put more of their growing effort into fruiting.From 1997 to 1999 MacNut Farm production has increased from 20 tons to over 40 tons of nut in shell.

 

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Growing Macadamias

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Macadamias thrive in the following conditions:

  • High rainfall
  • Well drained soil
  • Warm and frost free climate
  • Some wind shelter

Macadamia trees are extremely tough – in fact they’re quite hard to kill. They produce economic quantities of fruit after 8 years, although fruit will be borne in small quantities as early as two years. Trees live for 70 years or more, reaching a height of 20 metres. At MacNut Farms we have the ingredients for a successful orchard, although a little more warm weather wouldn’t go astray.

The growing year at South Head is broken into the following phases:

Flowering and Pollination: OctoberThe trees flower during October with long white and pink racemes making this the best time of year to visit the orchard. At this time of the year the orchard is home to beehives to assist in pollination and ceases picking operations to minimise disturbance to the flowers. The Beaumont hybrid that dominates at MacNut Farms has been planted with other varieties to improve its poor self-pollination.
Pest Control and Weed Removal: late Spring to AutumnOver the warm summer months the picking is finalised and the trees are sprayed with liquid fertilisers and veggie bug control agents. At the same time the prolific growth of weeds is controlled by sheep and maintenance around the trees. Further fertilising with mulch from the husks, chicken litter and some chemical fertilisers is completed at this critical stage of growth as the new nuts set and grow on the trees. Macadamia trees are biennial, alternating heavy and light cropping years.

 

 

Picking, Pruning: Winter and Early SpringAt the start of June the picking season begins. Picking in NZ is done by hand as the Beaumont hybrid does not drop it’s nuts.  In Australia mechanical harvesting from the ground is the norm. The racemes of nuts are clipped from the trees and are collected in nets placed on the ground.
It is common practice to have a pruning gang working just in front of picking gangs. In this way access to the trees is improved and high branches can be cut and left on the ground for picking. Over the past two years we have pruned the orchard to allow better air flow for pollination, more light ingress, better access for picking and allowing the trees to put more of their growing effort into fruiting.From 1997 to 1999 MacNut Farm production has increased from 20 tons to over 40 tons of nut in shell.

 

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