Frequently Asked Questions

Please find some helpful frequently asked questions that give you a quick solution to any queries or question you may have regarding our products.

What types of ice pack does Hydropac offer?

Hydropac currently offer 3 types of ice pack, with another coming to the line up very soon!

These are:

  • Water Ice Packs
  • Gel Ice Packs
  • HydroFreeze Ice Packs
  • Enviro-Gel (coming soon)

See the full range here:

Does Hydropac manufacture inhouse?

Hydropac produce and fill each ice pack on-site at their Buckinghamshire factory in the heart of the UK.

To do this, Hydropac have their own unique in-house machinery, designed and built by the Hydropac team of clever scientists and engineers! This machinery allows them to offer an unrivalled dosing system that accurately fills each ice pack to capacity.

Hydropac also have their own “Seal through Liquid” technology. This innovative breakthrough system means that each ice pack is completely sealed and extremely durable; Hydropac ice packs (water and gel) can withstand over 200kg of weight without bursting.

What’s the difference between a courier box and a freezer tray?

Courier Boxes are small boxes suitable to deliver small orders of ice packs to you by overnight courier, perfect for those with smaller requirements. They are available with a low MOQ of just 1 box. If you would like a custom printed ice pack then the MOQ is 2 pallets per production run, but this requires a commitment to a larger volume of film.

Freezer Trays have been designed for larger volume orders, so the ice packs can be frozen on the pallet in bulk. There is a 1 pallet (48 Trays) MOQ on these or just 2 pallets for custom printed ice packs then the MOQ is 2 pallets per production run, but again this will require commitment to a larger volume of film.

Freezer Trays have strategically engineered air-flow holes. These allow for a uniform freeze to the centre of the pallet and ensures the sheets will not stick together, unlike traditional “Soak & Freeze” packs.

Which is the eco-friendliest option?

Water ice packs will always be the eco-friendliest option, especially as the water ice packs Hydropac offer are the purest, cleanest and safest ice packs available on the market.

But if it must be gel, then keep watch for a new launch coming very soon – ‘EnviroGel’

Why are Hydropac ice packs so safe?

Every single ice pack made at our inhouse facilities, whether that be gel or water, has to pass rigorous QC processes. These include a 3-stage filtration process, softening, chlorination and finally being treated with UV light.

Once this has happened, quality-controlled samples are sent from every single production run to an independent lab for microbiological testing. As such, a full cleanliness and safety certification is provided for every single order leaving the factory.

Hydropac water ice packs have even been granted accreditation as “safe to ingest” by an independent microbiologist.

Full certification for Hydropac water ice packs can be found here:

Can Hydropac ice packs be customised?

All ice packs are supplied in a transparent film as standard, with the Hydropac logo on one side so that you and your customers can see the contents are not harmful. Proud of our outstanding adherence to quality and the fact that all of our ice packs are certified food safe, Hydropac adds their logo for traceability purposes too.

More on this here:

Hydropac can supply any of their ice pack range in any colour and print them with your own logo/information if you prefer. Printed and custom sized ice packs are always made to order and unrivalled low minimum order levels starting from just 2 pallets per production run are offered, but this will require commitment to a larger volume of film.

Water Ice Packs

What are the size options available for the water ice packs?

We offer 8 different size options: But we can make any size Ice Pack, just ask!

  • 500g – 12 pockets
  • 500g – 4 pockets
  • 750g – 6 pockets
  • 1kg – 8 pockets
  • 500g – 1 pocket
  • 250g – 4 pockets
  • 500g – 8 pockets
  • 1kg – 16 pockets

What is the difference between a 1 pocket pack and 8 pockets?

The single pocket ice packs (500g-1 Pocket) were introduced because the trend was moving towards low-cost ice packs, however, the multi-pocket ice packs work better and are more economical for larger boxes!


If you have a box of food ready to post, ideally you should fill the footprint of this box with ice, add your foodstuffs and then fill the top layer with more ice packs. This helps to achieve even temperature coverage throughout the box and the food within. Covering all the area will ensure that the food maintains a constant temperature throughout with no ‘hotspots’.

If you use the single pocket packs (500g-1 Pocket) you would need to use a considerable amount of them to cover the footprint that it becomes uneconomical, so a multi-pocket pack is the best choice to ensure the food is evenly chilled or frozen and importantly maintained throughout the journey.

Will water ice packs be at higher risk of leaking than gel?

No – all of the ice packs, regardless of fill, are burst strength tested to 200kg.

Is the water colourless?

Yes, Hydropac prefer the transparency of a fully clear ice pack, including the film covering.

Are pre-frozen options available?

Yes, see the Pre-Frozen Ice Packs available in both water and ice.

Why would you buy pre-frozen ice packs?

Pre-frozen ice packs are quite simply the pinnacle of convenience in the ice pack world, offering customers a quick solution if they don’t have the time to freeze down ice packs before shipping to their end customer.

They are delivered in full pallet lots on a 3-5-day service using frozen transport, so can be ready to send straight back out when they arrive.

Gel Ice Packs

What are the size options available for the gel ice packs?

The gel ice packs are available in 3 different size options: But can be made in any size required, just ask!

  • 500g – 2 pockets
  • 500g – 1 pocket
  • 500g – 8 pocket

What’s the difference between gel and water?

  • Water ice packs are made from pure, filtrated water that has been chlorinated, softened and UV light treated to be certified as food safe.
  • Gel ice packs are made from a unique, passive cooling, non-toxic polymer gel formula that is FSA & FDA approved. They are also completely food safe.

The only fundamental difference is that one is a gel and one is water; everyone has their own set of preferences, but the moral compass at Hydropac is firmly with the environmentally friendly water packs.

However! The gel (SAP – Super Absorbent Polymer) formula is a plastic derivative which is non-soluble and simply absorbs moisture, swelling in size when it comes into contact. The same SAP formula is used in babies’ nappies; for this reason, disposal is almost impossible and is most likely to find itself in landfill, polluting the water table or worst case in our seas at some point in its life. All of these reasons are why 95% of ice packs sold are pure water.

Hydropac’s mantra is to be as environmentally friendly as possible and they are set to launch a very new ‘patented’ gel ice pack which is being named ‘EnviroGel’ which will tick all these eco boxes and more – So watch this space!

Why are gel ice packs slightly more expensive?

Gel ice packs are slightly more expensive because of the cost of the formula that goes into them vs plain water. Simples.

HydroFreeze™ Ice Packs

What is ‘HydroFreeze™’?

Our HydroFreeze™ ice packs use a specially engineered phase change liquid that offers a Food Safe alternative to dry ice. They maintain a FSA & FDA approved product temperature of below -15°C when used with the insulated systems.

They must be frozen at a temperature at or below -25°C prior to use, to activate the phase change to a solid, so you must ensure your freezer is capable.

Why would you choose HydroFreeze™ over water or gel?

They have been specially engineered for use when transporting frozen food and will keep these goods at a constant frozen temperature.

Water or gel packs can also be used with frozen or chilled foods/goods, but you will need to use considerably more of them than HydroFreeze™ to provide the same effect… there’s science involved you know!

What are the size options?

HydroFreeze™ ice packs are available in 2 different size options, but can be made in any size to order; just ask!

  • 660g – 2 pockets
  • 500g – 1 pocket
  • 1.4kg – 8 Pocket

Are they colourless?

Yes, HydroFreeze™ ice packs are provided as a clear food safe liquid in a blue film. HydroFreeze™+ ice packs are provided in a white snowflake film.


How do I know which Hydropac products are most suited to my needs?

Selecting the right packaging for the shipment of food requiring temperature control is a critical element in delivering fresh produce with your customers time and time again. Hydropac can help all its customers with a “bespoke service” supporting them in the choice of the optimum combination of products.

Hydropac will need to know information such as:

  • Types of produce, i.e. meat, fish, cheese, etc.
  • Weight/Dimensions of produce
  • Shipment temperature required: ambient, chilled, or frozen.
  • Shipment duration
  • Existing packaging method
  • Customer information required on the outer carton
  • Estimated unit volume per month
  • Your projected monthly and/or annual demand
  • Interest in “post-it” back recycling bags

Are the Hydropac products easy to use?

What are the instructions for use?

Hydropac products are easy to assemble and use. To optimise the cooling efficiency, Hydropac recommends that its customers follow these simple instructions:

How do I know how many sheets/mats to use per customer order?

Hydropac have designed a unique interactive piece of software that enables calculation of the optimum number, size and weight of Ice Sheets to be used inside our Insulated Boxes, when tailored to your exacting requirements.
By entering as many variables as possible, Hydropac can provide the customer with a complete picture of the temperature controlled packaging solution.

Please call for exact details on 01494 530182.

Guide Purposes Only – Insulated Shipping Systems and Ice Sheets

Chilled Goods

30% ice of shipped goods
4-6 Kg Boxes require 2 – 4 x 500g Ice Sheets
6-10Kg Boxes require 4 – 6 x 500g Ice Sheets
10-15Kg Boxes require 6 x 500g Ice Sheets
20-25Kg Boxes require 6 – 8 x 500g Ice Sheets

Frozen Goods

50% ice of shipped goods
4-6 Kg Boxes require 4 – 6 x 500g Ice Sheets
6-10Kg Boxes require 6 – 10 x 500g Ice Sheets
10-15Kg Boxes require 10 – 15 x 500g Ice Sheets
20-25Kg Boxes require 10 – 14 x 500g Ice Sheets

How long do Hydropac products last?

At what temperature do the sheets/mats guarantee?

Ice sheets must be frozen to -18ºc in order to deliver optimum cooling performance during shipment. They are then guaranteed to keep produce below +8ºc during shipment as long as the correct numbers of ice sheets are used per Kg weight of produce.

How long do ice sheets stay at the required cooling temperature?

Ice sheets should not be removed from the freezer until you are ready to pack and seal your produce in an insulated box. Hydropac guarantee at least 24 hours cooling performance but can offer bespoke products to achieve in excess of 48+ hours where required.

How can I maximise the effectiveness of each sheet/mat/box?

To maximise the effectiveness of each product, Hydropac recommends that its customers:
1. Keep products at the lowest temperature before packaging, recommended, just above zero.
2. Wrap products in an insulating material such as “bubble wrap” to prevent Ice Sheets from freezing the produce.
3. Remove the ice sheets from the deep freeze (-18c) just before packing.
4. Place the ice sheets evenly across the top and bottom of the insulated box. If there is an odd number of ice sheets place the higher number at the bottom of the Insulated Box.
5. Add “dunnage” (e.g. bubble wrap, Void Fill) to prevent the products from moving around during transit. Do not use an excessively large box.
6. Once packed, ensure that the insulated box lid is fitted snugly and taped securely.

Can Hydropac products be recycled?

What materials are used in the manufacture of Hydropac products?

  • The foam liners within the Insulated Shipping Systems are made of closed-cell, non-cross linked polyethylene; a material that is fully recyclable through your normal household recycled collections; almost indestructible, waterproof, wipe clean and totally reusable. Please check your local authority if they collect LDPE. If not, you can dispose LDPE at your local supermarket plastic bag collection points.
  • Hydropac’s Thermal Postal Pockets are made entirely of LDPE materials and can also be recycled through your normal household recycled collections. Please check your local authority if they collect LDPE. If not, you can dispose LDPE at your local supermarket plastic bag collection points.
  • Hydropac’s Ice Packs (gel and water) are made entirely of LDPE material which is completely recyclable through your normal household recycled collections, but don’t forget to empty the water contents down the drain or even water your plants with it – remember, our water is the purest there is, your plants will love it! The gel however cannot be disposed of down the sink, it will need to be disposed of in your general waste! Please check your local authority if they collect LDPE. If not, you can dispose LDPE at your local supermarket plastic bag collection points.
  • We are also releasing an environmentally friendly, compostable version of the film that surrounds our ice packs. More on this to follow….
  • Carry Home Bags – what can we say, these also totally recyclable through your household recycled collections.
  • Reflective Air Bags – Unfortunately, despite being made of totally of recyclable materials, most recycling centres in the UK are not quite ready to separate the materials for recycling, but due to the very low weight ratio compared to other systems, the effective disposal costs are minimal.
  • The Polystyrene Boxes/Systems (made from EPS) can be recycled at any one of the following recycling centres throughout the UK.

Which of Hydropac’s products can be reused?

All of Hydropac’s systems are totally reusable, just wipe them clean and use them again. Even the ice pack range can simply be re-frozen and reused.

How many times can Insulated Boxes be reused?

All of Hydropac’s systems can be reused time and time again; provided the structure remains intact, the thermal protection will remain as good as new.

If end-users are encouraged to recycle Hydropac’s systems up to 5 times, then our customers can save around 29% on their packaging costs – it means, of course, less business in the long term for Hydropac, but as part of its commitment to the environment, this is more than outweighed by creating valuable customer relationships.

How do I handle Hydropac's Ice Packs

Hydropac’s ice packs are the toughest around, but when frozen they are vulnerable for a short time. Please read the Safe Handling Instructions For Ice Packs ; we are very precious about our little creations at Hydropac, so please play nicely with them!

Do you have another question?

Simply fill out the form below with your query and we will get back to you asap.

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