Salmon Stress Test for the AMARU Freeze Dryer

When we first started sketching out the concept of the AMARU freeze dryer years ago, we imagined the ideal batch load would be around 5 kg of raw product. We drew the chamber, tried fitting five product shelves inside, and 1 kg per shelf seemed “just about right.”

It soon became clear, however, that each shelf could hold more than just 1 kg of food, and we began routinely testing 7.5 kg loads. It is worth mentioning here that some of our customers were actually well ahead of us in these stress tests, with some of them already running loads of over 12 kg on a regular basis. Preparing, loading, and unloading the product are tasks that require at least one person, whereas once AMARU is freeze-drying, the operator can focus on other work.

Then YOGGIES came along — a Czech manufacturer of dog and cat food, which at the time was already operating 8 AMARU freeze dryers. They wanted to find out what the maximum possible load would be while still maintaining product quality. So for the test, I loaded 2.5 kg of poultry offal onto each product tray and started the process using the standard 5-shelf system, which was the standard setup at the time. The test went well, everything dried successfully, and the analysis carried out by the customer also confirmed excellent results. But by then, we already had a prototype of the 7-shelf system, so naturally one thought kept running through my mind: “What if...?”

Then, when 2026 began, all the necessary circumstances finally came together, and YOGGIES once again delivered product to my test room in Prague 6 — this time a full 20 kg of salmon pieces. When loading the same 2.5 kg onto each tray, you have to be careful not to let the product rise above the height of the tray frame. Once frozen, it becomes hard as rock, and any contact with the tray pressure plates — which in AMARU ensure perfect contact between the tray and the product shelf — would only create a mess.

This is what 2.5 kg of salmon on a single product tray looks like.

I will not keep you in suspense: the freeze-drying of the salmon once again went through without the slightest problem. From a total of 17.5 kg of raw product, almost exactly 6 kg of dried product remained after freeze-drying. That is not bad at all for a freeze dryer that was originally designed for a capacity of around 5 kg, is it?