I've been thinking a lot about oats (I know, get a life). NT says that lactobaccili and enzymes both have a role in phytate reduction, so even if the oat groats themselves have no native enzymes left (because of being previously steamed or roasted), if one is adding something like kefir to the soaking water then phytate reduction should still occur, just as when soaking oats for porridge. I don't know if any of the enzymes in kefir would be the same as those naturally in grains (and which are activated in a warm, wet environment), but you at least have the lactobaccili and acid. I'm unclear on the role of acid in the soaking medium, but NT calls for all grain soaking to be done with warm, acidulated water. If the study showing no significant phytate reduction from soaking whole grains used plain water, I don't see how it would apply, since we're not using plain water. Also, as for the matter of grains being whole when soaked rather than ground, the phytate content is in the bran (outer) layer, so the soaking medium should have no trouble penetrating that layer and doing its work. Maybe in the future I'll add a tiny bit of wheat for grain enzymes.
I'm going to continue to soak whole oat groats in water with kefir added, then dry and grind or flake them. I used them in a recipe just yesterday that turned out really nice, so I'll share it with you all. I'm calling them oatcakes, although I suspect they're not much like the recipe Catarina posted (which I intend to try). I wanted something very slightly sweet, dry but not hard, and easy. This fit the bill, I'm happy it turned out how I wanted 'cuz I was just winging it.
Maple Oatcakes
(These were made with whole oat groats that I soaked in water with kefir for about 18 hours, then dried and ground into flour with a grain mill.)
8 oz. ground oats*, plus about another 1/4 cup for kneading
1/2 tsp finely-ground sea salt
4 oz. cold unsalted butter, cubed (8 Tbsp)
1/8 cup maple syrup (2 Tbsp)
*this weight in oats amounted to about 2 cups ground, not packed, just the way it fell out of the grain mill and shaken slightly to level the top so I could see how many cups it was, I made it an even 8 oz. on the scale by adjusting by just a pinch, you could weight it before grinding as well, I don't know how much it was in volume before grinding
Place 8 oz. ground oats and salt in workbowl of food processor, pulse briefly to mix. Add cubed butter, pulse several times until evenly distributed but still coarse in texture. Add maple syrup, pulse briefly to mix, just until dough comes together. It will be slightly sticky at this point. Sprinkle remaining 1/4 cup oats on a board, turn dough out onto it and knead just until it gets less sticky and holds together better. Form into 1" balls, flatten each ball to about 1/4" thick on baking sheet lined with parchment paper. Brush tops with additional maple syrup if desired. Bake at 300 degrees F for 30 min.
I'm sure this could be made without using a food processor, it would just take longer, and you'd want to cut the butter in with a pastry blender so it doesn't melt with the heat from your hands, I think keeping the butter cold was part of what made these so tender, similar to why you want to keep the fat cold when making a pastry crust. You could perhaps adjust the baking temp and time as well, I wanted them cooked and dried out but not very browned so I kept it low and slow. These turned out very tender, just slightly sweet, and the flavors of oats and maple go together very well, they were a huge hit with my husband and our 5 year old. They were easy (in spite of my long-winded description), I think I spent less than 15 min. on prep.