The blanching is done to destroy any bacteria and the enzymes they may contain and so prevent spoilage. It also speeds up dehydration somewhat as many of the cell walls are already broken by the blanching. It is your choice.

I don't because I find it also changes the flavor of them IME and since I will only be using them in cooked dishes the cooking will cover the bacteria issue. So I just peel and wash well, coarse chop, spread on the dryer sheets, and dry them at 135 until fully dry and crispy. OUTSIDE or they will stink up the house.

The different temps just determine how fast or slow they dry. Mine take a good 10-12 hours at 135 but that too will vary based on the brand of dryer used.

Dave

I'm with Dave on this one... I peel, chop up in the food processor to a dice, then spread the onions out on jelly sheets... then into the dehydrator at 135. I use jelly sheets so that as the onion gets smaller, none fall through to the bottom. About halfway through the process, I turn the onions over on their sheets and re-arrange the trays in their stack. What results is a slightly toasted colored minced onion.

I dry my onions out in the solarium, just like I do with hot peppers- don't want to kill anyone with the aroma of those things drying, heh.

Note that I use a little Nesco round dehydrator, and not an Excalibur, so the turning of the onions and re-arranging the trays might be different with the Excalibur than it is with the Nesco.