[Robert]

I think glycoprotein "rest" (I'd rather say synthesis) starts around 70°C and continues through mash-off, as alpha activity continues:  mash-off does not fully denature enzymes, only boiling does; and lautering is not necessarily enhanced by mashing off, but conversion is -- I get the final ~2°P to 100% conversion at 76°C.  And killer foam.  (FWIW my program is 63°C 30 min 70°C 30 min 76°C 15 min, and should note I apply heat rather than using infusions.)

[hackrsackr]

I think glycoprotein "rest" (I'd rather say synthesis) starts around 70°C and continues through mash-off, as alpha activity continues:  mash-off does not fully denature enzymes, only boiling does; and lautering is not necessarily enhanced by mashing off, but conversion is -- I get the final ~2°P to 100% conversion at 76°C.  And killer foam.  (FWIW my program is 63°C 30 min 70°C 30 min 76°C 15 min, and should note I apply heat rather than using infusions.)

My point about the glycoproteins is that it is not a reason to raise the mash temp to 170f. Your great foam is more a result of your long 70c rest, and not the mashout (IMO), and the OP can get all the foam benefits with the temps he’s currently reaching. Like others have said, if 170f isnt easily obtainable I wouldn’t worry about it. 162f should be plenty for that.

Are glycoproteins synthesized, or extracted?

I’ve done tons of hochkurz (64,72c)mashes without a mashout and always get the same foam and extraction as when I do (HERMS). Maybe your direct fire heating is making starches burst and allowing alpha to get at it right at the end giving you the extra efficiency. 2 Plato seems like a lot of late extraction though.

The lautering thing is just about reduced viscosity. On our scale it may not be noticeable, but it’s real.

The denaturing is enzyme relative, alpha may survive for a while at that temp, but beta, proteolytic, beta glucanase, and the other lower temp enzymes should be pretty much fully denatured by a mashout. Either way it’s even less of a reason for the OP to do the mashout. Your extract efficiency bump would be the only reason to do it, but I’ve just never seen the same results in my own brewing. Time is the way I get to full extraction. 80 minutes seems to be the magic number for me.

[Robert]

I used to believe the mash-off was reducing viscosity to improve extraction in the lauter.  Then Denny kept saying it was just increased amylase activity at mash-off temps, and that viscosity vs. temp would not be a significant factor until wort density was in the range of 60°P or some such ridiculous number.  So I started monitoring my wort density pre- and post- 76°C rest, and what do you know, Denny may be right, it seems.  You may well be right in your assessment of the effects of my long alpha rest and direct fire, hackrsackr.   I'm only suggesting there may be some good reason for mashing off not related to viscosity effects in the lauter.  Denny's really shaken up my thinking, damn him!

(I'd say glycoproteins are "synthesized," as conjugates of medium-weight protein products [dependent on your protein rest or, really, avoidance thereof] and medium-weight carbohydrates produced by alpha activity.  That's my understanding.)

[hackrsackr]

That’s pretty interesting, and I think that’s a much better statement saying: the mashoff May get you some increased extraction.

That’s pretty much the understanding of glycoproteins I had. Just unsure about the actual function of it. Does the “synthesis” occur at alpha and the higher temp end of it help extract formed glycoproteins from the grain, or are the proteins and carbs extracted separately then combined outside of the grain at 70c or so?

[Robert]

My impression is the latter. I admit I've never read the papers on this, just secondary sources.  (There are a couple cited in Fix, and I think I have a couple others in cloud storage I've never gotten to.) But it makes sense that you have to have the elements first before combining them, and if they are products of protease and amylases...

On another point, your HERMS and my direct fire are obviously both affecting conversion efficiency in different ways.  The high(est) temp rest may be less relevant in your system. 

[hackrsackr]

Yeah I haven’t read much either. If you ever dig the papers out of the cloud; please share any insights.


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