Big Efficiency Drop When Doing A Step Mash

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Sean_SA

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Hi guys

I want to establish whether perhaps a step mash is to blame with this issue I experience.

I have brewed a few hefeweizens now. Every time I try to do a mash with a ferulic acid rest, my efficiency would drop drastically, from my usual 80% to 63-65%. When I did the mash without any steps I would hit the 80 efficiency mark.

I haven't been able to find something online that supports this but perhaps it may be isolated to the way I have to warm the water up to saccharification after the acid rest. I use a cooler box mash tun with no circulation so I have to add boiling water to bring the mash temp up. Is there a chance that the addition of the boiling water scorches the grain on contact? Again though, I haven't seen anything about anyone else experiencing this issue.

Mash PH has always been good so that is not a possibility.

Is there perhaps something else that could be causing this?
 

jdauria

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This is just a guess here...but when you are doing Hefeweizens you are using what, 50-60% wheat malt? Was your 80% numbers for beers without wheat? Wheat is smaller grain than barley and does not crush as easily in a mill. If you are milling at a homebrew shop or online store, their mill gaps are usually pretty wide, so a lot of the wheat may not be getting crushed. If milling at home, crush the other grain then reduce your mill gap and crush the wheat malt. Also, wheat can make a mash very sticky, use 1/2 lbs of rice hulls if you are not, they help to make the mash run smoother.

Another option...are you doing water additions to adjust pH? If so, don't make your additions until after the ferulic acid rest, that's a tip I recently learned from the book on German brewing my Kunze.
 

bracconiere

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do you batch sparge or fly sparge? if you're batch sparging and not getting the same volume for the second runnings?

maybe try doing a deccotion instead of adding boiling water, just scoop out some of the mash and bring it to a boil and add it back to the mash?
 
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Sean_SA

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This is just a guess here...but when you are doing Hefeweizens you are using what, 50-60% wheat malt?
I've been using 55% wheat malt.

Was your 80% numbers for beers without wheat?
No I've had 80% with and without wheat. To date I've done 5 hefe brews. The first 2 brews I did a step mash and got an efficiency in the 60's. The 3rd brew I got 80% but it had 2 differing factors from the previous two previous brews... 1. I used my own grain mill which I just bought 2. I didn't do a step mash. The 4th brew I did the same as the 3rd and got 80. The fifth I did a step mash and used 1/2 wheat malt I milled and 1/2 wheat malt milled at the HBS. The HBS sent me milled by mistake but the crush looked decent enough to me. That 5th brew dropped me down to 68% again.

Could very well be the grain crush then though looking back at this. Seeing as every time I've used HBS milled malt I've achieved a lower efficiency. The step mash must be coincidental then?

This was my mash schedule in my last brew:

Required mash water - 15.36L
  1. Ferulic Acid Rest at 45°C for 15 minutes in 7.3L of water
  2. After acid rest add 8.06L of boiling water to reach sacch temp of 68°C (calculated this in brewfather's rest temp calc)
  3. Let that sit for 60 mins and then continue as usual.
Is there anything about the process above that would somehow lead to a drop in efficiency? Considering the temps were hit accurately and the mash PH was good.
 
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Sean_SA

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do you batch sparge or fly sparge?
I batch sparge

if you're batch sparging and not getting the same volume for the second runnings?
Sorry I'm not quite sure what you mean. If you're referring to pre boil volumes I still hit those numbers fine.

maybe try doing a deccotion instead of adding boiling water, just scoop out some of the mash and bring it to a boil and add it back to the mash?
I also thought about this but I would need to decoct 8L of the mash in order to get to the correct mash temp. Wouldn't this scorch the grain and render it useless?
 

Holden Caulfield

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When I step mash I always use the boiling water method and do not see a change in efficiency from when I do single infusions, so from what I observe, using boiling water is not the cause. Perhaps your step mashing schedule results in significantly less sparge water?
 
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TheMadKing

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A step mash should increase your efficiency not decrease it in theory and in practice on my system. So something else must be in play.

68C is a pretty warm mash temp, normally when I do a step mash I do both a beta rest and alpha rest. At 154F you're definitely targeting your alpha rest more than beta, but that should not necessarily result in lost efficiency.

Are you stirring substantially after adding the boiling water to make sure the temperature and water are well mixed?

I agree with the idea above that it may be affecting your sparge water volume which makes a big difference.

Some things to try:
-mash longer, go to 90 mins
-stir every 15 mins during the mash
-let your batch sparge sit for a little longer OR switch to a slooow fly sparge (45 mins to an hour)
 

bracconiere

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I batch sparge

Sorry I'm not quite sure what you mean. If you're referring to pre boil volumes I still hit those numbers fine.

I also thought about this but I would need to decoct 8L of the mash in order to get to the correct mash temp. Wouldn't this scorch the grain and render it useless?
i was refering to the fact that if you're batch sparging and adding more water to your mash to begin with, you probably use less water for your second rinse so you don't get to much wort into the kettle, right? so less effec sparge? my guess at something.

i do deccoctions every brew, i just use my pressure cooker with the lid off to boil the mash, i don't really even need to stir it. takes like 3 or so fills to bring my 10 gallon mash up to 162 from 150. it seems to work?
 
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Sean_SA

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i was refering to the fact that if you're batch sparging and adding more water to your mash to begin with, you probably use less water for your second rinse so you don't get to much wort into the kettle, right? so less effec sparge? my guess at something.
Oh I see what you mean sorry. So I am not adding more water to the mash than would be needed. My brewing software indicates a required mash water volume of 15.36L ... so I split the 15.36 into two batches of water, one batch for the acid rest, and the other batch for the boiling water I need to add to ramp up temp. So I use 7.3L of water for the acid rest and then once the acid rest is done I add 8.06L of boiling water which makes up the required mash water volume of 15.36. This gets me to the target sacch temp.

I hope that's what you were referring to

i do deccoctions every brew, i just use my pressure cooker with the lid off to boil the mash, i don't really even need to stir it. takes like 3 or so fills to bring my 10 gallon mash up to 162 from 150. it seems to work?
Perhaps this is something I should give a go then. I'm still a noob to the brewing game so plenty to learn
 
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Sean_SA

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68C is a pretty warm mash temp, normally when I do a step mash I do both a beta rest and alpha rest. At 154F you're definitely targeting your alpha rest more than beta, but that should not necessarily result in lost efficiency.
I want to increase the FG a bit as the yeast attenuates quite a lot. That's why I go for 68
Some things to try:
-mash longer, go to 90 mins
-stir every 15 mins during the mash
-let your batch sparge sit for a little longer OR switch to a slooow fly sparge (45 mins to an hour)
Thank you for these tips. I do stir every about every 15 mins
 

tootal

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Do you need to do an acid rest? What's the PH of your water when you start? We set our PH at 5.8 for light colored beers and 6.0 for dark beers due to roasted malts lowering PH more. We also set our sparge water at 5.3. Crush, mash length, PH and how modified the malt is. (Kolbach Index) can all make a difference in efficiency.
 

marc1

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Do you need to do an acid rest? What's the PH of your water when you start? We set our PH at 5.8 for light colored beers and 6.0 for dark beers due to roasted malts lowering PH more. We also set our sparge water at 5.3. Crush, mash length, PH and how modified the malt is. (Kolbach Index) can all make a difference in efficiency.
Water generally doesn't have much buffering capacity, so targeting a water pH for the mash isn't usually useful. It's the mash pH that matters. What mash pHs do you get doing that?
 

Bilsch

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The OP said ferulic acid rest so it’s for clove flavors not mash pH.

My guess is the poor efficiency is related to how you mix your boiling water for raising temperatures and there is damage being done to your enzymes.
 

tootal

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Our mash pH is 5.1 - 5.3. The malt lowers it a little and we compensate for that since we start at 6.8 - 7.0. It's well water so it varies a little.
 
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