Sprouted grains - Home milling

I don't have a direct method of measuring moisture content in the grains I sprout, dry and mill. Instead I weigh the grain before sprouting and then 48 hours later  dry the sprouted grain until its weight is at or below the starting weight. I know this isn't perfect: some of the water absorbed is used up in the hydrolysis of starch to maltose and glucose (basically the weight of one water molecule is added to each sugar molecule cleaved from a starch molecule) but additional water is produced for each glucose consumed during oxidative metabolism. I use a tooth-test, biting into a wheat berry before sprouting and checking that a similar degree of hardness and dryness is achieved in the drying process. So far the milled result has been powdery and dry, no gumming up  or glazing of the stones.

The grains/sprouts can be spread on a baking sheet and dried in a gas oven with only its pilot flame burning.

Sprouting grain for a couple days activates enzymes some of which split starch into smaller molecules, notably maltose. Maltose feeds yeast. After dehydration and grinding many of the enzymes remain intact and able to continue to release more maltose from starches in the mix. But as the temperature of the grain goes above 113°F, more and more of the enzymes will become denatured: they will undergo irreversible structural changes  (think: frying an egg) and lose their ability to work.

My oven's pilot flame holds the interior at about 104°, perfect for making yogurt and dehydrating grain. In a different kind of oven it might work to cycle the oven on and off to keep it warm but not too hot. If malted (sprouted) grains are to remain diastatic as flour they cannot get too hot. If it's too hot to hold comfortably in your hand it's probably too hot for the enzymes.

Good info, Zoologuy!  I knew heat destroyed the enzymes, but did not know it was that low.  I would have just guessed to use a dehydrator @ 110º, but not with any actual knowledge in the subject.

Lörren,

What kind of oven do you have?  If you have a newer oven, esp. electric, it may be so well sealed that the grains may not dry well.  Even propping the door open slightly did not help much when a friend would try to dry things, and this was @ 150º - the lowest his oven would set to.  At an even lower temp., they may sour before drying.  If you have a gas oven, hopefully you have one of those pilots that hold your oven temp at a good level - mine is too hot (120-125º).  If yours is also too hot, you could try reducing the size of the pilot flame, but if you do, remember to put it back to about where it was (make a mental note, or take a photo of the location of the screw before changing).  If too small, it may not light the flame, or the influx of air when the flame lights may blow out the smaller pilot flame. 

An afterthought: maybe also try to place a small fan in with the grains you are drying.  Test it before placing something in to dry, maybe by putting one of those external thermometers in there with it, to see if it reduces the temp at all.

Dave