Instructables

Does anyone know how to dry a liquid to make a powder?

 I want to make stevia powder out of a concentrated stevia liquid? To store it longer and to use it in dry tea mixtures and so on.

grandpayum6 days ago

vacuum concentration/distillation may work. essentially putting the liquid under a vacuum causes the liquid to boil without having to heat it as much/at all. A rotary evaporator would do it but costs 2,000-15,000. alternatively you could hook a sidearm flask to a vacuum pump on a stirring hot plate for much less but it would probably take longer. A spray dryer would work but similarly costs a lot, however you can replicate the process with inexpensive tools (essentially the theory is that a slurry such as your stevia liquid is sprayed to fine particles into a hot chamber (350F+) and dried by the heat). It's touchy because too little heat will do nothing and too much will burn the powder but I've seen it done with a paint sprayer and a heat gun in an enclosed container (e.g. a pipe or trashcan depending on scale)

I believe that is called freeze-drying. I have always wanted to know how to do that but I never had the equipment to do it.
orksecurity3 years ago
The difficult thing is usually getting the liquid to evaporate quickly enough to keep it from being olonized by microbes (fermenting at best, getting moldy at worst), and without cooking the material or driving off essential oils you want to preserve, either of which could change its flavor.

Have you considered just freezing your concentrate into ice cubes, perhaps using one of the plastic trays which makes 1/2 inch cubes? You could then just toss an appropriate number of cubes into whatever you're using. (Credit for this approach goes to Ewel Gibbons, who used it to preserve jewelweed extract for later use.)

+1

As has been noted, making dry liquids is usually done using a vacuum process. Using conventional dehydration will evaporate all the aromatic oils from your Stevia, and it will potentially introduce harmful bacteria or simply result in spoil, so freezing in convenient measurements is probably the best you can hope for at home.
Just to evaporate it ? The big guys spray into vacuum chambers I think, so that flavours are preserved. Big open tray in the refrigerator, and mount a PC fan tray over it ?
hugenott (author)  steveastrouk3 years ago
You mean refrigerate the liquid? How do I have to mount the fan on the tray? Do you have a sketch of this idea? It sounds good.
iceng hugenott3 years ago
Take it ( your liquid ) down to the triple point.
That is what I think Steve was alluding to.
Takes a big sucking vacuum chamber :-)
Vyger3 years ago
Another thing that would work is one of those small food driers, the ones they use for fruits and berries and such.
hugenott (author)  Vyger3 years ago
Do you have any expereance with such food driers? Can I use a food drier for liquids? A food drier dries the inside stuff, by making the stuff warm inside and the liquid comes out of the stuff? What about an oven with an open door? The heat above 50°C and under 100°C so that nothing burnes inside?