2 step mashing question(Hochkurz Mash)

I started a frambozen, this last weekend and I roughly followed the easy all grain stove top method by death brewer from this site. I mashed the grain at 140F for 30 minutes in one pot with 2.85 gallons on water then mashed the grain at 158F for 30 minutes in another pot with 2 gallons of water. I combined the wort and did the boil. Fermentation took off after 12 hours and looks great. My question is what happens if I let the wort sit at 149F(or whatever the resulting combined temp is) for 20 minutes after I combine the worts? The 140F wort is highly fermentable wort with beta enzymes and the 158F wort is less fermentable wort with alpha enzymes. To what extend will the enzymes in the 140F wort start breaking down the long chain sugars from the 158F wort?

Thanks,
Nate

Here's is some info worth looking at:
http://braukaiser.com/wiki/index.php/Starch_Conversion

I don't have a simple answer for you as to exactly what happens, but not all the starches are gelatinized under 149*, meaning that although there is lots of beta-amylase activity, there is also lots of starch still "locked up."

"β-amylase is much better at producing fermentable sugars. In fact the way in which β-amylase hydrolyzes starches and large dextrines is the reason for the large maltose content in wort produced through mashing. It attaches to the non-reducing end of a glucose chain and clips off one maltose molecule after another. But because it has to do that at the non-reducing end its activity has to stop when it comes close to a branch point (α(1-6) link). In order to work on the glucose chains after the branch points it relies on the activity of the α-amylase which creates a non-reducing end every time it splits a glucose chain or the limit dextrinase which can break the branching α(1-6) link itself. In mashing α- and β-amylase work in concert: α-amylase creates substrate (i.e. non-reducing ends) for β-amylase. The process of creating sugars is called saccharification and happens mostly after the liquification of the mash. Mashes that intend to produce a highly fermentable wort always try to maximize the β-amylase activity. This is mainly done through the rest temperature(s) and the time spent at these rest(s) which will be discussed later"

Thanks for the reply, I found that article also -- interesting stuff. I think I'm going to try a few simple experiments where I do a 20 minute rest at 149F then move the grain to the second pot at 158F for 40 minutes. Then combined the wort into one pot and heat to 152F and rest for 30 minutes. At that temp the alpha enzymes can work on the starch from the 149F wort and the beta enzymes can work on the sugars from the 158F wort.

I think combined the wort would produce at 150F-152F wort so I probably don't need to add much heat to maintain the target

2.85 gal * 145F = 413 gal*F
2.85 gal * 149F = 424 gal*F

2 gal * 158 = 316 gal * F

(316+413) gal*F /4.85 gal = 150F
(316+424) gal*F /4.85 gal = 152F