I love to dehydrate things like vegetables and mushrooms. They'd be more convenient to me if I could turn them into powders so that I could easily add the powders to soups, or teas, or casseroles.
However, I run into a problem of not having the proper equipment to grind them...
I have a flour mill that does great with grains, but it doesn't work well with things like dried squash or dried garlic that have more sugar in them. It doesn't do well with anything that is very fibrous.
The meat grinder didn't work because it just augered more and more stuff into the barrel until it bent the blades.
The blender just tosses huge chunks of dried vegetable around and around.
The spice grinder blade broke rather than chop up chunks of dried garlic.
The holes in the coffe grinder are too small to handle chunks of dried squash, and it gets overloaded with more fibrous things like Turkey Tail mushrooms.
A mortor and Pestle, or a metate pretty much suck. They mostly just squish the squash chunks and flatten them out...
Is there a technique that I am missing? What would the proper equipment look like to make garlic powder out of dehydrated garlic? Or squash flour out of dehydrated squash?
I am just starting to experiment with this, and if I have enough surplus garlic to play with this year, it will be the first such surplus for me.
But I did make about a quart of oyster mushroom powder last fall, starting with two full loads of mushrooms in my five-tray dehydrator. What worked for me was to dehydrate them until they were as dry and crunchy as possible (think potato chip, dry enough to snap) and then run them through a food processor, with the standard twin blade. There was some dust generated in my kitchen and the resulting mix was not evenly-sized, ranging from flour up to about half the size of a BB. That was fine for soups.
Here's hoping people will chime in with easier and better methods!
I don't have an electric dehydrator, but I see that they come with sheets to make fruit leather. It may be that the sugars you mentioned will never let things dry completely. I think industrial processers might use something like freeze-drying to get extra moisture out, they probably have super pulverizers, and then they use anti-caking ingredients. I don't think you can expect to get the same results they do, but you might be able to come closer...
I wonder what a centrifuge juicer style grinding blade would do since it is designed to tear off small pieces with teeth. May still have fiber buildup issues and of course it is designed for wet rather than dry jobs so dust would go everywhere.
i have seen recipes for things that are like fruit leathers but are all vegetables and things and are used to make soups. i think some things will just never dry enough to be powder. i bet you could dice things so they are pretty small and then dry them though. it would not be dust but it would rehydrate quickly as a seasoning.
One thing I'd be concerned about would be the shelf life of powdered veggies. When you turn something into a powder, you are exposing way more of it to air, which will increase the rate at which you will lose nutrients etc. I find that for dried herbs, they stay far fresher if I leave them as whole as possible, then grind or crush them right before use.
Perhaps instead of powdering them ahead of time, you could make the soup with the chunks of veggies and then use a stick blender to puree the final product?
In my experience, the key is cutting them small before dehydrating, then fully dehydrating them so that they shatter when ground (like coffee beans). I have ground dried veg to near-powder in coffee grinders (reserved for spices), a small mini-food processor, and my larger food processor.
My favorite use for these is to make my own bullion powder: mix 1/2 cup powdered veg with 2 -4 Tbs arrowroot powder, 1 Tsp saltt, and several teaspoons dried herbs (parsley, dill, etc). Mix thoroughly and then mix in 2 Tbs natural oil (sesame, olive). Store in fridge for up to 6 months.
The oil coating keeps air off the veg so that flavor and nutrition are retained. This makes a GREAT soup base!
I would suggest that you shred your veggies before drying, think very fine julienne cut.
Once these are thoroughly dried they can be powdered in a heavy duty, dual blade chopper.
Commercial companies use hammer mills for this process but those are way to expensive for most people to even consider.
once you have created the powder, filter it through the finest strainer you can (metal coffee filters, are some of the finest and costs is around ten dollars)
bottle them in glass containers that have tight lids with a seal.
cut small to dry and then you can put them through a ninja food processor/blender. I dry beef jerky in small squares and it turns the stuff into powder for making pemmican. it would handle veggies and garlic like no problem. I use it to make smoothies and it takes down frozen strawberries and other solid frozen stuff like crazy. The thing is made of plastic and looks chincy but it really does the trick and holds up well. Got about 4+ years out of my first one, this one is made even better than the last one and I haven't even had to sharpen the blade.