Let me just say, this isn’t necessarily a recommended practise, do your reseach (as always) and decide if its for you.
I recently got 6 litres of milk for $1 each and decided to dehydrate them to make my own powdered milk. Most preppers order their powdered milk in #10 cans from various food suppliers in the US, however this is out of my price range and the tariffs Canadians have to pay on dairy are ridiculous.
To dehydrate my milk, first I had to make parchment paper containers to cover the screens in my Excalibur. I did this by cutting a square and folding up all the edges so they folded over themselves and then I stapled it just to be sure. Put the parchment on your screen and pour a small thin layer of 1% milk onto it. (I used 1% aka non fat milk because the more fat, the more likely it is to go rancid.
I cranked my dehydrator to 135′ F and left it over night. About 10 hours later it was ready. The milk turns into a crackly sheet in a sort of yellow color. At this point all you have to do it toss it in a blender or food processor and buzz it up until its a fine powder. Store it in a jar or mylar bag with an oxygen absorber.
To rehydrate, mix it with cold water and shake it until you get all the chunks out.