I try to choose seasonal foods for our tests. After all, it doesn't make sense to buy fresh strawberries in December to freeze-dry them for a rainy day. Well, what could be more seasonal during the cold and flu season?
Note: This test was performed on an earlier model of the AMARU lyophilizer. We have made several improvements since then and today the capacity would be higher and the process faster.
Preparation
I should state right off the bat that preparing the horseradish for freeze-drying was probably the most painful freeze-drying preparation I've experienced. A quantity of 8 kg of horseradish is normally cut just right at a slaughter, and even here several people take turns at this activity. I had one helper and around the third kilo a crisis came upon me when I had to go to the street outside the workshop to breathe.
In the end we managed to load up 3 produce trays with shredded horseradish, one tray we tried to cut the horseradish into rounds with the idea that it would be blended after drying. Since we ran out of material and needed to fill all 5 product trays, we loaded the last one with scraps. We had exactly 1 kg of usable horseradish on each of 4 product trays.
Freezing
Thanks to the smaller quantity, freezing to the required temperature was relatively quick. 12 hours was enough. If a larger quantity was loaded in AMAR, I would not be afraid to add an hour just to be sure.
Drying
Drying was also relatively quick. Here, however, it certainly helped that the horseradish is crumbled and therefore the water leaves the product without any obstacles. We stopped the drying at 32 hours, but if I ever make sliced horseradish again (like, ever!), it would be worth a try to check the status after 30 hours.
Result and rehydration
This time I've combined the two chapters into one video. Several people questioned whether horseradish would still have its spicy charm after drying. It was enough to bite off a little of one dried slice and it was clear that the absence of water concentrates the effect.
This is especially the case when rehydrating. Only a small amount of water can be added and what I call wasabi-horseradish is created. Normally, I probably take horseradish in portions like normal mustard, but I can dispense freeze-dried horseradish with a smaller proportion of added water with just the tip of a knife.
Just to add, out of every 1000 g before drying, 355 g remained after freeze-drying, i.e. about 35%.
Usage
Whether in the chopped or blended version, horseradish can be used to create a deliciously spicy horseradish paste. I can also imagine it as a spice or directly as a dry powder for various spreads and sandwiches.
If you are going to consider freeze-drying horseradish, it is still advisable not to hide your diving goggles :)