Different step mash schedules and their purpose

[Nemanach]

I am interested in learning more about what the different temps in step mash might achieve. I have read about acid, protein, beta and alpha rests but I want to find out what temps on either end of the range will do. For example I have seen step mash schedules start at 148 for 30 minutes then jump to 158 for 30 minutes. I have also seen 144 then 154. I've also seen 149 then 156. How would those three beers differ?

I am also interested in learning about the length of the rests. I have seen 20 minute beta rest and longer beta rests. I would assume a longer beta creates drier beer but by how much?

Can anyone suggest a resource I could use to learn about it? I have done some searching but I can't find anything that really dives into the different temps and their outcomes.

 

[DatsyukianDeke]

Best thing to do is grab a copy of New Brewing Lager Beer. Greg Noonan does a good job explaining what enzymes work in which temp ranges and where they experience peak activity.

ALso check out braukaiser's site. He goes in depth on the different rest temps and decoction mashing.

http://braukaiser.com/wiki/index.php/Braukaiser.com

 

[Qhrumphf]

Unfortunately much of this is gonna be variable primarily on ingredients (different maltsters are gonna vary with enzyme make up, and even the same grain from the same maltster may vary slightly lot to lot and year to year) but surely on your individual system and process as well.

So the best way to tell how a given malt with a given mash schedule will perform on your system is to try it.

Generally mashes with longer rests at lower temps will tend to fermentability, while higher temps and shorter rests will be less fermentable. Beyond that it's hard to be specific. What step mashing allows is a beer that is both well attenuated AND has a firm body. But where exactly that balance lies is the question.

As far as lower temp rests (beta glucan, acid, protein rests) I don't usually do them unless I have a reason. If I'm using an umdermodified base malt, or lots of adjuncts then yes, but otherwise there's seldom a need. The notable exception are German wheat beers- I'm a HUGE proponent of a long ferulic acid rest at 110F to bring out heavy 4VG in the finished beer.