A regular reader of our blog might almost think that we haven't posted anything for a while. Actually, our Lyon (the prototype of AMARU) has been under constant workload lately. Tests for customers have been interspersed with test crews trying out different parts, so there hasn't been that much news.
So I will use at least the last test set, when I asked Honza to provide something liquid for one test in the amount of 5 liters. I guess I was kind of expecting five cartons of milk, which would have been plenty, but my colleague solved it even a bit better - he brought five cartons of Eiskaffee (IceCoffee, EisCaffe, Icekaffe and a thousand other variations), specifically the German brand Hochwald.
Hochwald Eiskaffee contains a full 24% coffee ingredients, 70% is milk and over 7% is sugars. It is therefore more of a coffee milk with sugar (and no caffeine). However, it is worth mentioning that the coffee is indeed freeze-dried. In the production of instant coffee, the coffee extract is dried either in a spray dryer or in a freeze dryer, which is then one of the higher quality products.
Note: This test was performed on an earlier model of the AMARU lyophilizer. During 2019, we have made several improvements since then and today the capacity would be higher and the process faster.
Preparation
As with all liquid foods, the preparation is fairly easy and thus forms a counterpart to ice cream or cheesecake. Simply tear off the corner of the box and spread evenly onto the product trays. Of course, it's a good idea to have the trays already partially inserted into the shelving system in the chamber of the freeze dryer, as carrying a flat tray of liquid is one of the more advanced user's tricks :)
Freezing
The coffee was already at room temperature when it was poured, so it was up to the freeze-dryer to do the initial freezing all by itself. Lyon comfortably did the whole thing in 12 hours, when the entire contents of the chamber were below -25°C.
Drying
Due to the higher sugar content, there was a little concern that the test would end up like condensed milk or honey. We decided to stop the process after 29 hours.
Result
The result is not dissimilar to freeze-dried milk or yoghurt. The dried coffee has the texture of a moonscape, which when disturbed turns into flakes and these crumble into a fine powder. The sweet taste predominates considerably.
Rehydration
Even powdered milk can be rehydrated with milk :) However, I recommend using water, preferably in the original ratio (or even more water). Otherwise, you will get back a coffee drink, but an enormously sweet one.
Usage
Freeze-dried iced coffee doesn't have to be all that silly. In addition to the availability of iced coffee at any time from powder, just the powder can be used for various decorating or baking purposes. The concentrated powder could even replace sugar on any dessert, plus it would add the familiar coffee flavor.
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