Diastatic Power and Enzyme Denaturing

[¡Mung Fling!]

Hey everyone, I am doing Charlie Pap's 1554 (1447) recipe from Micro-brewed Adventures, partial-mash, and I am concerned about some things. This is my current mash recipe:

3lb. Munich Malt
1lb. Wheat Malt
1lb. Oat Malt
1lb. Caramel 120
.5lb. Caramunich 120

According to my calcs. this would give me a Diastatic power of 43, which I know is low, but it should still be able to convert right? Also, I am planning on doing the step mash suggested in the book which is a protein rest @ 132ºF for 30min. and raising to 155ºF for 30min. My concern is that the beta-amalayse won't really do anything at 132ºF and it will be denatured too fast at 155ºF that with such a low DP there won't be enough for proper conversion. What do you all think? I can always sub some Munich for 6-row, but if I don't have to I'd rather not (since the munich extract is already 50%-ish base malt). Thanks so much for your help; this question is making me a bit crazy.

[spiderwrangler]

When you say Munich extract I assume you mean that the rest of the recipe calls for a Munich extract? Munich is a bit lower in enzymes, but they are there, and the wheat will contribute enzymes as well. Is it an oat malt you are using or flaked? The Cara malts you don't have to really worry about conversion wise. Keep in mind that while the amylase enzymes won't be super active at 132F, you aren't really looking for that there (although there will be SOME activity). With the mash at 155F and the grains in the malt bill, I'd say that the partial mash in this beer is probably looking to give you a bit more body and longer chain sugars, so you aren't really trying to go for something really highly fermentable here. I think it'll probably be fine, you can always let it sit a bit longer at sacch temps if you don't think you have full conversion.

[¡Mung Fling!]

Yes, the rest of the recipe is Munich extract. Indeed, it is oat malt I'm using not flaked oats. If I took the cara malts out of the equation for the DP would that be a more accurate number? It's worth mentioning that the OG is 1.057 and the FG should be 1.016 so it's not supposed to be super fermentible. Thanks for the input!

[spiderwrangler]

The cara malts won't be contributing or benefiting from DP, so I'd say you should just go with it.

[BDawg]

Wheat malt has a very high DP even higher than the DP of 6 row. Briess' white wheat malt has DP 190, lintner, their red is 200 lintner.

I've read conflicting reports online about the DP of oat malt. I've seen some reports that it is low, and others that say it's about the same as 2 row. In general, the you can guess that wheat and oats sum up to contribute more DP than the Munich, and the cara malts are already converted, so you have nothing to worry about conversion wise.

Also, don't worry about the 132 rest. 131F is the low end of beta activity, and the high end of protease activity. You will essentially be doing a combo protein & beta rest at 132. I use this temp often with wheat beers and it works well.


HTH-