CALM (Controlled Atmosphere Long Life Module)

- Storage System for Chestnuts and Other Nuts 

Postharvest Fresh has developed a system that enables nuts, such as chestnuts, to be stored in in high quality condition for up to one year, rather than the few months currently possible.


Chestnuts have a brief harvest period of a few weeks, but are sought after by consumers throughout the cooler months of the year. Unfortunately, chestnut quality during storage is compromised due to the occurrence of black surface mould.

CALM Technology

The basic principle of the CALM technology is storage under high carbon dioxide with sufficient oxygen levels maintained. Each CALM unit can be used to store 1-4 bins (400 to 1600 kg or 0.45 to 1.8 tons) of chestnuts. After harvest, excess moisture is removed and bins are sealed on a pallet base within a plastic sleeve. The CALM unit is then attached to the bag via an air-tight interface with an oxygen sensor and tubing going through the interface to provide adequate fresh air to the chestnuts and to maintain the ideal storage atmosphere (see photos). CALM is powered by l2V DC power, so that only safe low power cables occur within the cool rooms.  Besides Sydney Postharvest Laboratory, the technology is also owned by Horticulture Australia (on behalf of Australian chestnut growers).  It is recommended that the technology be used as part of a complete handling and storage protocol (Postharvest Handling and Storage Protocol for Chestnuts).

Current CALM module (V7)

CALM Module V7

Mould control

Chestnuts store well with very little mould development under the high carbon dioxide and low oxygen atmosphere controlled by CALM .  The CALM system is as effective as the best fungicide control, but without the use of any chemicals.  Storage of nuts for up to 12 months (in excellent condition) is now achievable, compared to about 3 months, previously found to be the commercial storage limit.

Further Information

Grower's Experience With CALM Unit  Ray and Carolyn Young, Allen Creek Farm, Washington, USA
 "the nuts were in excellent condition when we removed them from the unit on Nov. 25. We sent out well over 200 orders from that tote and received not one single complaint about bad nuts. This has never been the case before. 
Our goal was to pay for the unit with the savings achieved in having good nuts to ship in late November-December. It not only did that but paid for our trip [to Australia]
as well. 
...  We are sold on the CALM unit."

Postharvest Handling and Storage Protocol for Chestnuts

Article about development of CALM technology and results.

PDF   You will need Adobe's Acrobat Reader to view the PDF files.

CALM system (Version 6)

CALM in Coolroom

(The CALM technology is available most countries, with distribution restricted in some countries under the license terms with HAL. These restrictions are based on providing Australian growers with an advantage in the global market.
Purchase can either be completed via the PayMate Purchase basket below
    - or by requesting an invoice via email or fax (give postal and fax details).




Price A$ (ex GST)



CALM Basic System (CALM Unit including pump and oxygen sensor, pallet bag interface, pallet bag, internal tubing and connectors, DC power supply, pallet base sealing components minus wood, replacement pump)
CALM Module



CALM Unit (including pump and oxygen sensor) CALM Module



Pallet bag interface
Pallet interface



Pallet bag (4.5m x 2.5m plastic tube)
Pallet bag



Internal tubing and connectors Internal connections



DC power supply (can run up to 5 units) Power pack


6* (or 7)

Pallet base sealing components minus wood Sealing Components



Pallet base (wood base 1200x1200x12mm and sealing system) Pallet Base



Extension Cable for running 5 units from one power supply EXtension cable



Replacement oxygen sensor Oxygen sensor



Replacement pump



Extension power cable - 10 m (30 ft)  Staight extension cable



Packet of 10 Large Cable Ties




Side by Side Bin Connector (connects 2 stacks of 2 bins each) to run from one CALM  unit

Bin connector


Postage and packaging one Basic CALM System (to Australia) (for other countries please enquire)


Postage and packaging one Basic CALM System to USA (for other countries please enquire)


or Postage and packaging Basic CALM System (to Australia)and complete pallet base (Item 7) (to Australia) (for other countries please enquire)


The simplest way to purchase multiple units is to select one of each item you require, adjust quantities in the shopping basket, then select <Update Basket> to check quantities and total cost     

* For a basic unit, components required are marked with*, (you need one option from Item 6 or 7)

# For multiple units consider combinations of extension cable (Item 7) and DC power supplies (Item 5)

It is recommended, especially when running multiple units, that a spare pump(s) be purchased and also a spare  DC power supply.

If you have any queries please email or ring +6194908443 or +61410603170


TO HOME PAGE      Postharvest Fresh    Revised  June 2009  (S.Morris)