Vacuum Cooling Mushrooms – What Is the Best Way to Chill Mushrooms After Harvest?
For commercial mushroom growers, getting mushrooms from harvest temperature to the correct storage temperature as quickly as possible can have a major impact on product quality, shelf life and customer satisfaction.
Mushrooms are particularly sensitive after harvesting. They contain a high percentage of water and continue to respire after picking. If field heat is not removed quickly, deterioration can accelerate, potentially resulting in discolouration, moisture loss and reduced shelf life.
This is why vacuum cooling mushrooms can be such an effective post-harvest cooling method.
Unlike conventional cold-room cooling, which relies on cold air gradually removing heat from the outside of the product, vacuum cooling removes heat rapidly and much more uniformly throughout the load.
For mushroom farms processing significant volumes every day, those minutes can matter.
Why Do Mushrooms Need to Be Cooled Quickly After Harvest?
Once mushrooms are harvested, they continue to respire.
The warmer the mushroom remains, the faster many of the processes associated with deterioration can continue.
Rapidly removing this heat can help growers maintain:
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Product quality
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Appearance
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Firmness
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Shelf life
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Consistency between batches
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Cold-chain integrity
The objective is therefore not simply to put harvested mushrooms into a cold environment. The objective is to remove the heat from the mushrooms themselves as rapidly and uniformly as practical.
This is where vacuum cooling becomes particularly interesting.
What Is Vacuum Cooling?
Vacuum cooling uses the relationship between pressure, water and temperature.
Fresh mushrooms are loaded into a sealed vacuum chamber. Powerful vacuum pumps then reduce the pressure inside the chamber.
As the pressure falls, the boiling point of water also falls.
A very small amount of moisture within and around the product begins to evaporate at a low temperature. The energy required for this evaporation is taken from the product itself, rapidly removing heat.
The result is extremely fast cooling without relying solely on cold air travelling around the outside of boxes or trays.
You can view the complete Cold Change vacuum cooling range.
How Quickly Can Vacuum Cooling Cool Mushrooms?
For suitable mushroom loads and correctly specified equipment, vacuum cooling can potentially reduce mushroom temperature dramatically in a relatively short cycle.
Based on previous Cold Change mushroom cooling applications, a typical commercial vacuum-cooling cycle can be approximately 12–15 minutes, although actual cooling time depends on several factors including:
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Starting temperature
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Required final temperature
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Mushroom variety
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Weight per pallet
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Packaging
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Pallet configuration
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Number of pallets
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Vacuum system capacity
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Refrigeration capacity
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Loading and unloading time
The machine therefore needs to be correctly sized around the farm’s actual production.
At approximately 12–15 minutes per cycle, a commercial mushroom vacuum cooler can potentially complete around 3–4 cooling cycles per hour.
Vacuum Cooling vs Cold-Room Cooling for Mushrooms
A conventional cold room is extremely important for maintaining mushrooms at the correct temperature.
However, using a cold room to remove large amounts of heat can take considerably longer because heat must transfer from the mushrooms into the surrounding cold air.
Vacuum cooling approaches the problem differently.
Cooling occurs throughout the load rather than relying entirely on cold air gradually penetrating boxes and pallets.
For a high-volume mushroom operation, this can create a major operational advantage.
Instead of harvested mushrooms spending a prolonged period pulling down in temperature, pallets can potentially be rapidly pre-cooled before entering refrigerated storage.
The cold room can then perform the job it does best: maintaining already-cooled product at its required storage temperature.
Can Vacuum Cooling Extend Mushroom Shelf Life?
Rapid removal of heat is an important part of maintaining fresh-produce quality.
For mushroom growers, even a modest improvement in saleable shelf life can potentially have significant commercial value.
Rapid pre-cooling followed by an effective cold chain can help:
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Reduce rejected product
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Reduce waste
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Maintain product quality
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Increase potential transport distances
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Provide greater flexibility for retailers
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Improve export opportunities
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Improve product condition when it reaches the consumer
For growers supplying supermarkets or exporting mushrooms over significant distances, the cold chain begins almost immediately after harvest.
This is one of the major benefits of vacuum cooling mushrooms and vacuum chilling mushrooms.
What Size Vacuum Cooler Does a Mushroom Farm Need?
There isn’t one machine size that suits every mushroom farm.
A smaller grower may only need to process one or two pallets per cycle, while a large commercial mushroom operation may require multiple pallets every few minutes.
Cold Change therefore offers a wide range of commercial mushroom vacuum coolers.
Mushroom Vacuum Cooler Sizes and Potential Throughput
| Vacuum Cooler Size | Typical Mushroom Cooling Cycle | Approx. Cycles per Hour | Potential Capacity |
|---|---|---|---|
| 1 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 3–4 pallets/hour |
| 2 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 6–8 pallets/hour |
| 4 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 12–16 pallets/hour |
| 6 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 18–24 pallets/hour |
| 8 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 24–32 pallets/hour |
| 10 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 30–40 pallets/hour |
| 12 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 36–48 pallets/hour |
| 14 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 42–56 pallets/hour |
| 16 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 48–64 pallets/hour |
| 18 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 54–72 pallets/hour |
| 20 Pallet Vacuum Cooler | 12–15 mins | 3–4 | 60–80 pallets/hour |
Cooling times and throughput figures are indicative. Actual performance will depend upon starting temperature, target temperature, mushroom weight per pallet, packaging, loading and unloading time and system specification.
1 Pallet Vacuum Cooler for Mushrooms
A 1 pallet vacuum cooler can provide a compact entry point into vacuum cooling for smaller mushroom farms, specialist producers and businesses processing relatively small batches.
At approximately 3–4 completed cycles per hour, potential capacity could be around:
3–4 pallets per hour.
2 Pallet Vacuum Cooler for Mushrooms
A 2 pallet vacuum cooler or 2 pallet vacuum chiller can be particularly attractive for smaller and medium-sized mushroom farms.
At approximately 3–4 cycles per hour, a two-pallet machine could potentially process:
6–8 pallets per hour.
This allows smaller growers to benefit from rapid commercial vacuum cooling without installing a large industrial chamber.
4 Pallet Vacuum Cooler for Mushrooms
For farms requiring greater capacity, a 4 pallet vacuum cooler provides a significant increase in throughput.
At approximately 3–4 cycles per hour, potential throughput increases to:
12–16 pallets per hour.
This can make a four-pallet system particularly useful for medium-sized mushroom farms where freshly harvested product continually arrives at the pack house.
6 Pallet Vacuum Cooler
A 6 pallet vacuum cooler provides another step up in production capacity.
At approximately 3–4 cycles per hour, potential throughput becomes:
18–24 pallets per hour.
8 Pallet Vacuum Cooler
An 8 pallet vacuum cooler can potentially process approximately:
24–32 pallets per hour.
For larger farms, this can offer significant throughput without moving immediately to a 10 or 12 pallet chamber.
10 Pallet Vacuum Cooler
Large commercial mushroom growers may require significantly greater throughput.
A 10 pallet vacuum cooler operating at approximately 3–4 cycles per hour could potentially process:
30–40 pallets per hour.
This allows significant quantities of freshly harvested mushrooms to be rapidly pre-cooled before entering cold storage, packing or refrigerated distribution.
12 Pallet Vacuum Cooler
A 12 pallet vacuum cooler increases potential capacity to approximately:
36–48 pallets per hour.
For high-volume mushroom production, this type of capacity can help prevent the pre-cooling stage becoming a bottleneck during peak harvesting periods.
14 Pallet Vacuum Cooler
A 14 pallet vacuum cooler could potentially process approximately:
42–56 pallets per hour.
This size can be suitable for major mushroom farms and centralised packing operations processing substantial daily tonnage.
16 Pallet Vacuum Cooler
A 16 pallet vacuum cooler can potentially provide:
48–64 pallets per hour
at approximately 3–4 cycles per hour.
18 Pallet Vacuum Cooler
An 18 pallet vacuum cooler could potentially process:
54–72 pallets per hour.
This type of system is designed for very high-volume commercial cooling operations where throughput and turnaround time are critical.
20 Pallet Vacuum Cooler
For the largest applications, a 20 pallet vacuum cooler could potentially process approximately:
60–80 pallets per hour
when operating at approximately 3–4 completed mushroom cooling cycles per hour.
Cold Change also offers a 20 pallet Eco Model vacuum cooler for customers considering alternative high-capacity configurations.
How Do I Choose the Correct Size Vacuum Cooler?
Buying the largest machine available is not necessarily the best solution.
The correct mushroom vacuum cooler should be selected around the actual harvesting and packing operation.
Important factors include:
Peak hourly production – rather than simply average daily production.
Pallet weight – two farms producing the same number of pallets may have very different tonnage.
Harvest temperature – mushrooms entering at a higher temperature require greater cooling duty.
Required final temperature – this directly affects refrigeration capacity.
Working hours – a farm operating one shift may require a different system from a facility processing continuously.
Future expansion – allowing additional capacity can avoid replacing the machine as production increases.
Loading method – pallet trucks, forklifts, conveyors and automatic loading systems can all influence machine selection.
Cold Change can therefore manufacture the chamber and cooling system around the actual application rather than forcing the grower into a standard configuration.
Example: A High-Volume Mushroom Farm
Consider a mushroom farm harvesting several tonnes of mushrooms during a production shift.
If mushrooms arrive at the pack house faster than the cooling system can process them, a cooling bottleneck develops.
Increasing chamber size alone does not necessarily solve the problem.
The complete system needs sufficient:
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Vacuum pumping capacity
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Refrigeration capacity
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Condensing capacity
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Chamber volume
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Loading capacity
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Controls
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Product throughput
This is why Cold Change systems can be configured around the customer’s actual production requirements.
Why Packaging Matters When Vacuum Cooling Mushrooms
Packaging is an important consideration.
The vacuum must be able to act effectively throughout the pallet.
Boxes, trays, films and pallet configuration can therefore influence the cooling process.
Before specifying a commercial mushroom vacuum cooler, Cold Change can consider the customer’s existing:
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Mushroom trays
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Boxes
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Pallet dimensions
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Pallet weights
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Wrapping
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Daily production
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Harvest temperatures
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Required dispatch temperature
This allows the cooling system to be designed around the farm rather than forcing the farm to work around the cooling equipment.
Does Vacuum Cooling Cause Mushrooms to Lose Water?
Vacuum cooling works through controlled evaporation, so a small amount of moisture loss is inherent in the process.
However, this needs to be considered in the context of the entire post-harvest process.
Mushrooms can also lose moisture during prolonged conventional cooling and storage.
The objective is therefore to achieve the required temperature reduction efficiently while carefully controlling the process.
Correct vacuum control, refrigeration capacity and cycle programming are important.
A properly engineered system should not simply pull the deepest possible vacuum. It should control the process according to the product being cooled.
Why Refrigeration Capacity Matters
A vacuum pump alone does not make an effective vacuum cooler.
When moisture evaporates from mushrooms under vacuum, that water vapour needs to be managed.
Commercial systems therefore require correctly selected refrigeration and condensing equipment as part of the overall process.
For large mushroom farms, undersizing the refrigeration system can compromise cycle performance.
The system should be engineered as a complete cooling process rather than simply as a vacuum vessel with pumps attached.
Automatic Vacuum Cooling for Mushroom Pack Houses
Modern mushroom pack houses increasingly depend on automation and repeatability.
Cold Change vacuum coolers can incorporate automatic operation, automatic doors, PLC controls and conveyor systems depending on the application.
A typical automated process could therefore be:
Harvest → Pack → Palletise → Vacuum Cool → Cold Store → Dispatch
For larger facilities, pallets can potentially enter and leave the vacuum cooler automatically as part of the pack-house material-handling system.
This can reduce manual handling while helping the grower maintain consistent cooling cycles.
Monitoring the Mushroom Cooling Process
Data is becoming increasingly important throughout the fresh-produce industry.
Rather than simply knowing that a cooling cycle has finished, growers increasingly want to know what happened during that cycle.
Modern vacuum cooling systems can provide monitoring of information such as:
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Cycle times
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Product temperatures
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Vacuum levels
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Energy consumption
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Cooling performance
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Service requirements
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Fault conditions
For larger growers, this information can help identify changes in cooling performance and production bottlenecks.
Energy Efficiency and Mushroom Cooling
Cooling fresh produce requires energy regardless of the technology used.
The important question is how effectively that energy removes heat from the product.
Vacuum cooling is particularly attractive where rapid cooling is required because the process directly exploits evaporation from the product to remove heat.
Correct equipment selection remains essential.
An oversized machine may create unnecessary capital cost, while an undersized machine can create production bottlenecks and excessive operating hours.
The objective should therefore be to match the vacuum cooling system to the farm’s real production profile.
Can Existing Mushroom Farms Retrofit a Vacuum Cooler?
Yes.
A vacuum cooler does not necessarily need to be incorporated when a mushroom farm is originally constructed.
Systems can potentially be installed alongside an existing pack house or cold-storage facility, subject to space, services and product-handling requirements.
Important considerations include:
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Available floor space
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Electrical supply
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Refrigeration arrangement
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Drainage
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Pallet access
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Forklift routes
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Conveyor integration
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Condenser location
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Service access
Cold Change can also manufacture customised solutions where standard dimensions do not suit a particular installation.
Vacuum Cooling Mushrooms in New Zealand
For mushroom growers in New Zealand, product quality and efficient cold-chain management can be particularly important where mushrooms must travel significant distances between the grower, distribution centre and consumer.
Rapid vacuum pre-cooling can be incorporated directly into a mushroom pack house, allowing harvested mushrooms to be cooled before entering cold storage or refrigerated distribution.
Cold Change supplies vacuum cooling equipment internationally and can design systems around local pallet dimensions, production capacities and site requirements.
Vacuum Cooling Mushrooms in Australia
Australian mushroom growers can face substantial distribution distances and high ambient temperatures in some regions.
Rapidly removing heat after harvest before product enters refrigerated storage can therefore be particularly valuable.
A commercial mushroom vacuum cooler can form the first stage of the post-harvest cold chain before cold storage and long-distance refrigerated distribution.
Vacuum Cooling Mushrooms in Canada
For mushroom growers in Canada, rapid pre-cooling can provide the same advantages.
Despite Canada’s cooler climate during parts of the year, mushrooms still require carefully controlled post-harvest temperatures.
A mushroom vacuum cooler can provide a repeatable cooling process regardless of outside weather conditions.
Vacuum Cooling Mushrooms in the UK and Europe
The UK and Europe contain significant commercial mushroom-growing industries supplying supermarkets, food-service companies and wholesalers.
Retailers increasingly demand consistent product quality and shelf life while growers simultaneously need to minimise waste and maximise production efficiency.
Rapid pre-cooling can form an important first stage of that cold chain.
Cold Change is a UK-based cooling-equipment supplier offering vacuum cooling systems internationally.
Is Vacuum Cooling Only for Mushrooms?
No.
Vacuum cooling can be used for a range of suitable fresh produce and other products.
Applications can include:
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Mushrooms
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Lettuce
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Broccoli
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Cauliflower
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Asparagus
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Spinach
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Herbs
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Celery
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Flowers
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Turf
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Bakery products
This can be particularly valuable for growers and packers handling several different products throughout the year.
Vacuum Cooler for Sale – What Should Mushroom Growers Look For?
Growers searching for a vacuum cooler for sale should consider more than the number of pallets that physically fit inside the vessel.
The important question is:
How many kilograms or pallets must be cooled to the required temperature every hour?
Pump capacity, refrigeration capacity, chamber dimensions, controls, loading method and cycle time all need to work together.
A machine capable of holding many pallets but taking considerably longer to cool them may ultimately provide less useful hourly production capacity than a correctly engineered system.
Cold Change offers individual machines covering:
or growers can view the complete Cold Change vacuum cooling range.
Is Vacuum Cooling the Best Way to Chill Mushrooms From Harvest?
There are several effective methods of cooling mushrooms.
Cold rooms remain essential for refrigerated storage, while forced-air and blast cooling can provide practical pre-cooling solutions for many growers.
However, where the priorities are:
Speed + Uniform Cooling + High Throughput + Product Quality + Cold-Chain Performance
vacuum cooling can offer significant advantages.
With mushroom cooling cycles potentially around 12–15 minutes, vacuum cooling can provide commercial growers with an extremely fast method of removing heat following harvest.
For high-volume growers, exporters and producers supplying demanding supermarket and food-service markets, vacuum chilling mushrooms immediately after harvest can therefore be an option worth serious consideration.
Frequently Asked Questions About Vacuum Cooling Mushrooms
What is vacuum cooling?
Vacuum cooling is a rapid pre-cooling process in which pressure is reduced inside a sealed chamber. This allows a small quantity of moisture within the product to evaporate at a low temperature, removing heat and rapidly reducing product temperature.
Can mushrooms be vacuum cooled?
Yes. Mushrooms can be particularly suitable for vacuum cooling because of their high moisture content and physical characteristics.
How long does it take to vacuum cool mushrooms?
Based on previous Cold Change mushroom cooling applications, approximately 12–15 minutes per complete cycle can be achievable with correctly sized equipment.
Actual cooling time depends upon starting temperature, target temperature, pallet weight, packaging and system specification.
How many vacuum cooling cycles can be completed per hour?
A 12–15 minute mushroom cooling cycle can potentially allow approximately 3–4 completed cycles per hour, depending upon loading and unloading arrangements.
Does vacuum cooling extend the shelf life of mushrooms?
Rapid removal of product heat followed by an effective cold chain can help maintain mushroom quality and contribute to a longer commercially useful shelf life.
Is vacuum cooling faster than cold-room cooling?
Vacuum cooling is specifically designed as a rapid pre-cooling process, whereas a conventional cold room is normally intended primarily to maintain already-chilled product at its required storage temperature.
The two systems can therefore work together.
What size mushroom vacuum cooler can I buy?
Cold Change offers 1 pallet, 2 pallet, 4 pallet, 6 pallet, 8 pallet, 10 pallet, 12 pallet, 14 pallet, 16 pallet, 18 pallet and 20 pallet vacuum coolers.
Can an existing mushroom farm install a vacuum cooler?
Yes. Vacuum cooling equipment can potentially be integrated with existing harvesting, packing and refrigerated storage facilities.
Can Cold Change build a custom mushroom vacuum cooler?
Yes. Vacuum cooling systems can be configured around specific pallet dimensions, production capacities, temperatures, loading arrangements and site requirements.
Find the Right Vacuum Cooler for Your Mushroom Farm
The objective of pre-cooling is simple:
Remove product heat as quickly and efficiently as possible and establish the cold chain immediately after harvest.
For commercial mushroom growers, vacuum cooling mushrooms and vacuum chilling mushrooms can provide an extremely rapid route from harvest temperature towards the required storage temperature.
With correctly selected equipment capable of approximately 3–4 cycles per hour, systems can be sized for everything from smaller farms using a 2 pallet vacuum chiller to major commercial mushroom operations using 10 pallet, 14 pallet, 16 pallet, 18 pallet or 20 pallet vacuum cooling systems.
Cold Change can assess your:
Pallet weight + mushrooms per pallet + harvest temperature + required final temperature + pallets per hour + operating hours
and recommend an appropriate cooling system.
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