I was recently reading about how roasting nuts at high temperatures can create acrylamide, a potential carcinogen in humans. I don't think the threat is massively serious at this time, but cooking anything at high temps definitely alters it from its original, native state. So, cooking at lower temperatures probably produces a healthier, more nutritious end product. And in most cases, eating seeds, nuts and veggies raw is probably ideal for health and nutrition standpoint, but not always for taste.
However, I have found that to make an Almond Butter that we like, both in consistency and flavor, raw almonds just don't cut it. I used to roast the almonds at 350° F for about 12 minutes, producing a fairly dark-roasted nut that came out of the oven snapping and crackling and smelling of freshly popped popcorn. Mmmmm. And that will still produce a nice, smooth, great-tasting Almond Butter, if not the healthiest.
Recently, I tried to roast the almonds at 300° F for about 20 minutes and the results were dismal. The nuts weren't roasted enough so the resulting butter wasn't very smooth and the flavor suffered. I should have roasted them longer, but I didn't want to ruin an expensive batch of almonds.
After reading a paper on acrylamide formation in almonds, I decided to try a really low (260° F) roasting temperature for a solid 60 minutes. The result was what I was after. The roasted almonds were so good, I started eating them right off the pan! Admittedly, they give up a little of the smoky flavor of nuts roasted at higher temps, but the resulting butter was about as good as we have had from a smoothness and taste standpoint.
So that's my new standard for roasting almonds, whether for Almond Butter or for snacking!
And we've just published our recipe (and a video!) for making Almond Butter.