I can’t seem to get a 155 degree mash (16 lbs. grain, 4.25 gals. water) to 170 degrees without adding a huge amount of water to mash out. I added 2.5 gals. at 195 degrees and only got to 166 degrees. I’m pushing the limits of my 11 gallon mash/lauter tun. What am I doing wrong?
Greetings kevinsimons - according to BeerSmith, 16 pounds of grain at 155 degrees F will need 3.25 gallons of water at 175 degrees F to increase the mash temperature to 170 degrees. Without knowing all the exact particulars of your concern, that’s the best I can offer.
When I try to raise temps via infusion I use boiling water. That said, there’s a good chance you don’t need that mashout step anyway.
I’ve never gotten to 170 F either. I typically use 190 F water or thereabouts, which only brings temperature to roughly 160-ish. I think we should be using boiling water to get there.
If you’re going to immediately runoff then bring up to a boil, then the mashout doesn’t matter anyway. Mashout is really only useful if/when we need to delay the boil for several hours or days later, which is rare.
You’re not doing anything wrong. I batch sparge and after the first run off (with no mashout), I strive to get the grain bed to 170F +/- a couple degrees. This past weekend I hit 168F. Close enough.
Mashout? Meh, it’ll get to 170F in the kettle, ;D just make sure you can hit your mash temps
Most times when when I mash out, or sparge, I feel like I barely raise the mash temp, even if the water is boiling. I’ve never played around with calculating how much water, at what temp, to add, to get a certain temp. Most importantly the starting temp is what I am aiming for, which is think is much more critical. I do like to do a very hot rinse after I have transferred to kettle though.
Rinse those grains.
The equations popularized by John Palmer for boiling infusions are useful here:
Vadded = ( ( Tdesired - Tcurrent ) * ( ( 0.05 * R ) + Vtotal ) ) / ( 212 - Tdesired)
Obviously the 212 in the denominator is boiling water. The 0.2 from the original equation changes to 0.05 so that we can use gallons instead of quarts.
There are a few assumptions you have to make here:
1.) Your current temperature is accurate, i.e. most people just use the temperature they mashed at in the calcs when it may have dropped lower over the course of the mash;
2.) That you are still at 212 degrees when you add the water.
So for your case:
Vadded = ( ( 170 - 155 ) * ( ( 0.05 * ( 4.25 / 16 ) + 4.25 ) ) / ( 212 - 170)
Vadded = ~ 1.52 gallons of boiling water
Let’s try to apply a real world fudge factor here and assume that you lost 2 degrees over the course of the mash and that the boiling water cools a bit to 208 before infusing:
Vadded = ( ( 170 - 153 ) * ( ( 0.05 * ( 4.25 / 16 ) + 4.25 ) ) / ( 208 - 170)
Vadded = ~ 1.90 gallons of boiling water
A mashout is beneficial IF you get it into the 172 range and HOLD it for at least 10 minutes. Without bogging down anyone with the science behind it, the mashout/mashoff is a foam-enhancing mash step and holding it for a duration of 10+ minutes bolsters the production of compounds known as glycoprotiens, which are foam positive.
I have found that those aren’t even in the ballpark if you mash in a cooler.
Right. You need to account for heat loss in the mash and heat loss in the boiling infusion for it to be accurate.
I think Denny was pointing out that you also have to account for the heat capacity of your mash tun.
Yep. And that cooler is built to resist temp change
One thing I’ve been accounting for is the actual temp of the “boiling” water. The difference between 212 and 208 can make a huge difference.
Right, which is obviously one of the thermodynamic “hand waves” that Palmer used to simplify the equations. I’m just saying mostly that the assumption that most people make is that the water is at 212 when they infuse. I can only speak for myself, but there is a lag from heat off to infusion for me and the water is usually around 207-208 by the time I infuse.
That obviously makes a bigger difference than the oft quoted drop in mash temp.
I’m open to suggestions and conversation about it though as i’m experimenting with a cooler again for step mashing.
Pretty sure that the temperature for a glycoprotein rest is 72c or 162f, not 172f. In the alpha range, not the mashout. Only reasons I’ve ever heard for a mashout is enzyme denaturing and easier lautering.
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.
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.)
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?
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.