[AmandaK]

So, we've all heard that there is definitely a difference between mashing with a single infusion and mashing using a step Hochkurz. Better malt character/better attenuation/better efficiency with the 145F/158F of the Hochkurz, etc. I believe(d?) it. I did it. I probably even spouted the same thing as fact.

But is there really a difference?

Now that we have a Zymatic and can perform very precise measurements/procedures, I'm giving a real comparison a shot. I've brewed two identical German Pilsners using these two mashing techniques, taking readings at nearly every chance I could. I dumped the logged data out, overlaid the gravity readings, and now I'm sharing.

Recipe, for each brew day:
German Pils - based on Wort HOG's recipe
Batch size: 2.5g
OG: 1.053
FG (anticipated): 1.012
IBU: 53
SRM: 5
-------------------------
5.5 lbs Best Pilsner
4 oz Carapils
4 oz Melanoidin
-------------------------
Bru'n Water: Yellow Dry
Ca 40, Mg 8, Na 8, SO4 91, Cl 29
-------------------------
60' - Herkules - 15.8% - 0.35 oz
15' - Vanguard - 4.8% - 0.75 oz
15' - Saaz - 3.5% - 0.5 oz
-------------------------
WY2206, 2L starter in 5L flask. Shaken, not stirred. Pitched at high krausen.

Beer #1 (150F):
Mash times/temps: 104F dough-in for 10', 150F sacc rest for 80', 175F mash out for 10'
Target mash pH: 5.45
Actual mash pH: 5.47
Pre-boil SG: 1.051
Target boil pH: 5.0-5.1
Adjusted pH in 'kettle' to 5.01, 1.8mL 88% lactic
Post-boil SG: 1.053
Fast-ferment test (w/ bread yeast, expected to be 0.2 Brix high): 1.013



Beer #2 (145/158F):
Mash times/temps: 104F dough-in for 10', 145F beta rest for 40', 158F alpha rest for 20', 175F mash out for 10'
Target mash pH: 5.45
Actual mash pH: 5.47
Pre-boil SG: 1.051
Target boil pH: 5.0-5.1
Adjusted pH in 'kettle' to 5.01, 1.8mL 88% lactic
Post-boil SG: 1.053
Fast-ferment test (w/ bread yeast, expected to be 0.2 Brix high): 1.013



Full data set here.

Several interesting observations:

• There is a huge difference in speed of conversion between 145F and 150F. The 150F mash converted in about 30' while the 145F mash never got to the same conversion in the 40' and only reached that same conversion during the 158F rest. I thought it would be slower, but I didn't think it would be that much slower.
• Each batch had EXACTLY the same gravity. The Z is basically a fully recirculating "brew in a bin" HERMS, I'm not sure if that has something to do with all of this, but it should be said.
• I'm also surprised at the work the mashout did on increasing the gravity. Here, it increased the SG by 17%. This is similar to what I've seen for other batches on the Z (+16-17%) for the mashout.
• The fast-ferment test indicated exactly the same FG for these batches, which also goes against what I've thought in the past. (More malt flavor, more fermentability.)

Some pictures:
Actual brew day, for the uninitiated:


The fast ferment test all set up:


Right after pitching the Hochkurz one (pitched the 150F about 12 hours ahead of time, since that was brewed in the morning and the other in the evening):


These have been rocking since 11/22/2015, and I'm about to take my first gravity readings and samples tonight. Pitched at 48F, fermented until 11/29 at 50F, now at 56F.

I do hope to do blind triangle tests on these and maybe trick some local judges into filling out scoresheets on them. We have some really great tasters in the area, so perhaps they could provide more insight/detail than "yes it's different" or "they are the same". _{(I wanted to do this on the Kolschs, but the beer did not turn out like I wanted, so it was not given out for that purpose.)}

[blatz]

any chance you can have this done before Saturday?  am brewing a marzen with a hochkurz mash profile starting at about 6am   

in all seriousness, waiting to see what you find out. 

[HoosierBrew]

Thanks for taking this one on, Amanda. I'm looking forward to the results.

[AmandaK]

any chance you can have this done before Saturday?  am brewing a marzen with a hochkurz mash profile starting at about 6am   

Haha. Well, I'll be updating tonight with some readings and general tasting notes, but that's about all I'll have by then. 


PS - I may try flipping the mash rests for my Dunkel (145F for 40'/158 for 20' compared with a 145F for 20'/158F for 40') and seeing how that goes. I gotta say, my main joy in the Z is that I can do these experiments with little consequence! 

[blatz]

PS - I may try flipping the mash rests for my Dunkel (145F for 40'/158 for 20' compared with a 145F for 20'/158F for 40') and seeing how that goes. I gotta say, my main joy in the Z is that I can do these experiments with little consequence! 

yeah I was planning 145 for 20, 158 for 40 as per my normal for a maltier type lager, but what are you hoping to get out of altering the times? 

[denny]

There is a very good reason I gave up doing decoction mashes a long time ago, and you've found it...

[AmandaK]

PS - I may try flipping the mash rests for my Dunkel (145F for 40'/158 for 20' compared with a 145F for 20'/158F for 40') and seeing how that goes. I gotta say, my main joy in the Z is that I can do these experiments with little consequence! 

yeah I was planning 145 for 20, 158 for 40 as per my normal for a maltier type lager, but what are you hoping to get out of altering the times?

Per Kai's site here, near the bottom of the page:

The first rest (maltose rest) should be held at or around 63C (145F) and it’s length is used to control the fermentability of the wort. A good starting point for its duration is 30 min. Longer for more fermentable wort and shorter for less fermentable wort. If even higher fermentability is desired an intermediate rest at 65C (150F) can be added.

So the question is: does it really control the fermentability at all?

[rabeb25]

Your test is flawed. You should have doughed in at 150 for this to make a difference, You stepped them both there.....

[rabeb25]

There is a very good reason I gave up doing decoction mashes a long time ago, and you've found it...

 Alas, this thread isn't about decoction but..If this is referring to a long ago "test" you did, you never completed the decoctions properly to begin with, so I don't doubt you saw no benefit.

[mabrungard]

The increase in extraction due to mashout is not a surprise. I typically see 1 to 2 Brix increase in gravity from pre- and post-mashout wort. Not surprisingly, the lower your final saccharification temperature, the greater the effect of the mashout rest. So you should see more of an increase in the 150F wort than seen in the 158F wort.

I'm looking forward to hearing the results of this trial.

[AmandaK]

Not surprisingly, the lower your final saccharification temperature, the greater the effect of the mashout rest. So you should see more of an increase in the 150F wort than seen in the 158F wort.

That's what I would have thought, but the (limited) data doesn't support that. Both mashes 'maxed' at 1.047 before mash out and both mashes were at 1.051 after mash out.

The increase in extraction due to mashout is not a surprise.

I was surprised at the % increase. I believe I calc'd my efficiency jump with a mashout on my old system to be about 4-5%. Definitely wasn't ~17%, which is what I've measured on now 4 different brew days. Probably a function of the recirculating 'brew in a bin' system, if I had to speculate.

[denny]

There is a very good reason I gave up doing decoction mashes a long time ago, and you've found it...

 Alas, this thread isn't about decoction but..If this is referring to a long ago "test" you did, you never completed the decoctions properly to begin with, so I don't doubt you saw no benefit.

I, and all the others who participated, simply did what homebrewers do.  Are you saying that there's only one "proper" way to do decoctions?

[dmtaylor]

Intriguing experiment!  Thank you for sharing.

I wonder what happens if you skip the mashout step and just bring the runnings straight to a boil as quickly as possible?  Do you still get a few extra gravity points from heating up the wort towards the boil, or is a separate mashout step required to get those extra points?

Also I wonder how my standard 40-minute mash would stack up against your 80-100 minutes.  My less formal experiments proved to me myself that I would only lose maybe 2 gravity points, and still save a big chunk of time on brew day.  I understand time is not of the essence to everyone, but it is to some.  If I can keep my brew day at 3.5 to 4 hours from milling to everything cleaned up, I call that a very good brew day.

[AmandaK]

Welp, I took two hydrometer samples tonight. Both beers are currently at 1.021 and still chugging along. We are at 56F and steady for now.



I tasted both of them, which of course I am biased, but this is preliminary at best. They have the same aroma as far as I can tell. The flavor is where it seems different, but they are very similar. The Hochkurz is more pronounced graham cracker, a touch of honey, and a light hint of graininess. The 150F, while very similar, is more grainy, similar honey notes, but less graham cracker. Mouthfeel is the same.

I had these out when Myles came home and asked what the difference was. He is also aware of the nature of this experiment but did not know which was which. He spent a while on the aroma, but immediately picked out the flavor of the Hochkurz to be more rounded.

Will this perceived difference hold up in the end? Not sure, but I'm looking forward to finding out.

[reverseapachemaster]

I wonder how much of the alleged increase in efficiency from a Hochkurz mash is system-dependent. For example, does the grain milling or design of the mash tun make the supposed benefits of a particular mash schedule on efficiency more or less probable? I know for my smaller mash tun (a two gallon cooler) I have to mash on a mid-140s/upper-150s split to get high mash efficiency and a low FG for my saisons. Mashing for the typical 153F for sixty minutes does not produce the same results. I have less of a problem on a larger ten gallon cooler. I wonder if the design of the Zymatic is inherently more efficient for mashing than coolers and other typical homebrewing equipment.