Beer Forum

Hi all (this is my first post on this forum)!

I am planning to start using hochkurz infusion mashing (where you do two different saccrification rests at around 145F and 160F). I know that the normal order of doing these rests are in increasing temperature order, but I am thinking about reversing the order to run the alpha amylase rest first (until starch conversion is done) and then follow with the beta amylase rest to determine the body of the beer by breaking down the dextrins.

Is there a good reason not to run the rests in reverse? I am thinking that the overall mash time should be shorter (same time for alpha rest - shorter time for beta rest due to more available sugar molecules) and that it would be easier for me since I could do infusions with room temperature water to bring down the mash temperature.

From what I understand, decreasing mash temperatures won't work for step mashes. Ashton Lewis explains why in his book, "The Homebrewer's Answer Book." If I remember correctly, I think at the higher temperature you will denature the beta amylase enzymes, which is an irreversible action.

Correct, it won't work. It's also why most brewers do a 'mash out' by raising the mash to 165-170. You're denaturing the rest of the enzymes, i.e. killing them off. When you step up, each step is favorable to a certain set of enzymes, but not warm enough to get the 'higher' enzymes working. When you raise the temperature to the next step, you denature (kill) the lower set while making the conditions more favorable for the next step.

Ok, thanks for your quick replies. I'll do it the right way (tm). Checking the temperature where beta amylase starts to denature it seems you are absolutely correct - beta amylase denatures at a significant rate above 149 (source: Steve Parkes in BYO).

I imagine most of the beta enzymes would be denatured at the higher temperature and the ones that aren't would have already done what they can. You could add some liquid beta enzymes to the mash but I don't see the point.

I do a Hochkurz step mash on most of my lagers now. I generally do 30 minutes at 144 and 30-45 minutes at 156-158. If you can increase temp with something other than infusions, you could probably hit the low temp and let it sit for a few minutes and then start ramping up and get the same effects.

+1 on denaturing the beta when at the alpha temps.
Egg whites turn white when cooking for this exact reason. They are denaturing, and you can never get them back to liquid form.

A single decoction works GREAT for boosting the temps in this case. You get the added benefit of the melanoidan development too.

BDawg wrote:A single decoction works GREAT for boosting the temps in this case. You get the added benefit of the melanoidan development too.

I will absolutely try a decoction when it is suitable for the style. I am actually considering switching to hochkurz mashing even for non-german styles where the melanoidans may not be what you want. Why Hochkurz for something where a single infusion would work? I like the idea of using time rather than temperature to control the fermentability - it is much easier to control (in theory at least).

I think if you modified Hochkurz to slightly lower temperatures, and went instead from say 155 F down to 145 F, the beta enzymes might not get killed so bad as they would at 160 F and you might be alright.

On the other hand, as a general rule I think step mashes are silly. I mash 90% of my beers at 148-152 F for 40 minutes and call it good. Works great for nearly every style. Why mess around if... there's no benefit from messing around!? Go ahead and play, but with experience you might come to agree with this conclusion.