Step Mashing

I was wondering if anyone with step-mashing experience could help me woth this question:

If you are only doing an alpha-amylase as well as a beta-amylase daccharification mash step, what combination of temperature and mash times, would you use to equate to a dry, fermentable wort (equivalent to a single-infusion mash of about 148-9)?; and what combination of temperature and mash times, would you use to equate to a sweeter, less fermentable wort (equivalent to a single-infusion mash of about 153-4 F)?

I haven't found any literature that explains how these two step-mash temperatures work together.

Thank you!

 

Thanks for the links and all the responses. The step mash regime that I used was 131 F for 15 minutes (Protein Rest), 140 F for 15 minutes (beta rest), and 149 F for 45 minutes (beta/alpha rest). I would have thought the 149 F temperature would have resulted in a relatively dry beer, but instead, it was medium (slightly sweet), even though my F.G. was 1.004. So somehow the 140 F step must have somehow contributed to the sweetness. I just wish there was some literature on how these saccharifcation combinations work together.

 

Thanks Jack! I'm looking forward to reading these!

 

How did you come up with this arrangement? Does it end up dry, sweet, or medium? Is this for lagers or ales?

 

Do you recall any literature/documentation recommending this approach?

 

I'm using a pressure fermenter, so other than the oxygen introduced during fermentation, there is no additional access to oxygen. It is still in the fermenter (just finished a diacetyl rest) so the sample was directly from the fermenter. At such a low F.G. (I use a TILT), I cannot understand why it doesn't taste more dry than it would appear to be based on the results. I assumed it might have something to do with the step mash.

I have checked the TILT against a hydrometer, and it is within a point or two at the S.G. end, and almost consistent at the F.G. end, using a specal hydrometer focused only at the lower end.

 

It was a 5 gallon batch, and the OG was 1.042 (lower than what I had planned for).
Hop schedule:
0.53 oz Magnum @14.1% Alpha for 60 minutes
0.70 oz Tettnanger @4.1% Alpha for 15 minutes
0.70 oz Saaz @2.8% Alpha for 15 minutes
0.30 oz Hallertauer Mittlefruh @3.6% Alpha for 0 minutes
0.30 oz Saaz @2.8% Alpha for 0 minutes

The last two hop additions were added shortly after flameout for 15 minutes.
The water profile was very low mineral (3/4 Reverse Osmosis; 1/4 tap water).
[Resultant profile: Calc: 10; Mag: 2; Sod: 4; Sulf: 7; Chl: 7]

 

The IBU was about 30-35 IBU
In terms of grain, I used the following:

8.89 lb of Weyerman Floor-Malted Bohemian Pilsner
0.20 lb of Carapils
0.10 lb of Melanoidin Malt

 

Thank you. I've seen the BYO article before, but look forward to to reading the Braukaiser article (I might have also read that one long ago).

BTW, does anyone know what happened to Braukaiser? He used to post some amazing articles about brewing lagers, and then suddenly, he was never heard from since.