I wonder what will happen to your mash if you change step order, under 154 °F. let say your original step as follow : 122 °F 20 Min 149 °F 30 Min 158 °F 30 Min If you do it 149 °F 122 °F 158 °F what will happened beside the warning you get from your brewing software ? Or lets say you forget to do the first (122) step and start with 149 and finish it, any good reason to go back to 122 ? Obviously it's a waste if energy.
When you let the mash rest at 149 F beta-amylase enzymes will do the saccharification step(converting fermentable sugars) but protease enzymes will be deactivated(these enzymes break protein chains),protease enzymes perform their best work at around 122 F, so when you low down mash temp to 122 F those enzymes will not work properly because of the previous step, it would be a false step.When you warm up temp to 158 F alpha-amylase enzymes will perform their best work converting starches into dextrines(less fermentable sugars)and beta-amylase enzymes are being deactivated and wil not work properly due to this high range temperature. Again , if you low down temp. to 149 F beta-amylase enzymes will not work properly because of the previous step. Sorry, too much complicated to my poor english.
When you're doing a step mash, you're really giving the enzymes at play (mostly alpha and beta) a chance to shine at the best temperature for them. Mashing at lower temperatures lets the beta-amylase enzymes do their thing, and mashing at higher temperatures lets the alpha-amylase enzymes do their thing but at the expense of denaturing (and basically destroying) those beta-amylase enzymes. So I don't think you'd get any benefits because going down in temperature wouldn't allow you to take advantage of those beta-amylase enzymes (as they'd be out the game already). But at the same time it depends on how long your steps are too. Killing off all the enzymes would take some time, though probably not too much.
Don't worry too much, Ilanko's English isn't so great either. However, what you said was perfectly clear and correct.
What would you like to know? Step mashing can achieve quite a few different things, ranging from ease of runoff to flavor to fermentability and mouthfeel. However, different enzymes work best at certain temperatures, and are often denatured (cease to work forever) at higher temperatures. In your example, the protease enzymes (the ones at work during a protein rest) will be denatured at above 140F or so. Going back after starting at 149F will just slow down the Beta rest, but won't do anything to help break down any proteins, as those enzymes will have already stopped working. It will also take much more energy to get back up to 158F.
