Triple Decoction Mash Problem

[felipefranco]

I've tryed my first triple decoction mash this saturday.
I used 9 lbs/4,1kg of pilsner malt and 0,74lbs/0,34kg of cara-pils
I used 16,4 qts/15,54l of water hitting a ratio of 1,68 qts/lbs and 3,5 l/kg
My steps were:
1- Dough in at 95F/35C and rest for 20mins
2- Take first decoction. 5,43qts/5,14l
3- Raise temp of first decoction to 158F/70C, rest for 20mins for conversion
4- Boil first decoction for 10mins
5- Return to main mash to hit 131F/55C. Do it in 10mins
6- Rest for 5mins
7-Take second decoction. 7qts/6,68l
8- Raise temp of second decoction to 158F/70C, rest for 20mins for conversion
9- Boil second decoction for 10mins
10- Return to main mash to hit 150F/65C. Do it in 10mins.
11- Rest for 30mins for conversion
12- Take third decoction. 6,7qts/6,36l
13- Boil third decoction for 10mins
14- Return ir to main mash to hit 170F/76C and rest for 10mins.

I did steps 1 to 9 perfectly. Both decoctions had a full conversion and all the temps were hit exactly.
The problem was that the main mash didn't convert in step 10.
I let it there for more than a hour at 150F/65C and nothing happened. Tried to raise to 158F latter and still nothing.
After 2 hours of waiting and watching the starches laughing at me, I decided to add more pilsner malt and managed to convert it all.

Do you know what could have gone wrong? I've done everything as expected and listed above.
Could that 2 decoctions had inactivated all the enzymes?

Thanks!

 

[felipefranco]

Correction:
I did steps 1 to 11 perfectly. And the mash didn't convert in step 11.

 

[Yankeepride15]

Did you take only the thick portion of the mash for your decoctions? If you removed X quarts of thick and thin (grain & liquid), it's possible that you denatured the enzymes.

 

[felipefranco]

Yes. Forgot to say that.
I only took the thick part of the mash in both decoctions.
Can't say for sure the ratio, but it was preaty close to what you can see at 1:30 of this video:

 

[Yankeepride15]

Thanks for clarifying, I used that same series of videos as my primary research prior to my first decoction mash as well. As far as your difficulty in conversion, I'm stumped. Sorry.

I also found a Brewing TV episode that called for removing 1qt thick portion for each lb of grist. I've used that and found it effective.

 

[felipefranco]

Thanks for clarifying, I used that same series of videos as my primary research prior to my first decoction mash as well. As far as your difficulty in conversion, I'm stumped. Sorry.

I also found a Brewing TV episode that called for removing 1qt thick portion for each lb of grist. I've used that and found it effective.

I watched that video too.
That's why it's so awkward to me why it didn`t work.

 

[BigEd]

Correction:
I did steps 1 to 11 perfectly. And the mash didn't convert in step 11.

How do you know it didn't convert? I'm guessing it did and you had a false negative. Did you taste it?

 

[VladOfTrub]

Since, it converted with the crushed malt, indicates denatured enzymes, but not always..... The vid is a rough schematic of decoction mashing. IMO it was the brewers 1st or 2nd attempt. The reason that I believe that, is because, he has excess, decocted mash left, that had to be cooled down before being dumped into the mashtun. After doing a few decoctions, using about the same weight grain bill. The volume of mash pulled, to be boiled, to hit a rest temp becomes a constant...Did the iodine change color in both decoctions, after the conv. rest in the decoction kettle? You may not want to assume conv. took place in 20 minutes because some one said it should. Mash pH is important. When you pull the 1st decoction, the pH will be higher than the 2nd decoction pH. The higher pH of the 1st decoction, favors alpha enzymes. The 2nd decoction pH will be lower, because, the mash in the tun was held at 100F or close, for a longer time period. The lower pH of the 2nd decoction favors beta enzymes. The ideal mash pH should 5.2. Alpha optimum pH is 5.7, Beta optimum 4.7. pH 5.2 is in the center. Sauer malz or lactic is used to reduce mash pH. I use 2 pounds of sauer malz in a 25 pound grain bill for all tri-decoctions, using RO water adjusted.....If you experience no color change in the iodine test of the main mash after 45 minutes of resting at conv. temp., add a little more water. Then, check after a few minutes. You may have converted, but the mash thickness was too great and perhaps due to a crappy crush. The iodine turned black because you may have tested liquid pulled from starch loaded husk material. When you added the crushed malt did you add more water to the mash? A thick mash benefits the enzymes, but when it comes to conversion, it may need to be thinned a little. Keep at it, you'll get there after awhile. It will come from experience..

 

[felipefranco]

Since, it converted with the crushed malt, indicates denatured enzymes, but not always..... The vid is a rough schematic of decoction mashing. IMO it was the brewers 1st or 2nd attempt. The reason that I believe that, is because, he has excess, decocted mash left, that had to be cooled down before being dumped into the mashtun. After doing a few decoctions, using about the same weight grain bill. The volume of mash pulled, to be boiled, to hit a rest temp becomes a constant...Did the iodine change color in both decoctions, after the conv. rest in the decoction kettle? You may not want to assume conv. took place in 20 minutes because some one said it should. Mash pH is important. When you pull the 1st decoction, the pH will be higher than the 2nd decoction pH. The higher pH of the 1st decoction, favors alpha enzymes. The 2nd decoction pH will be lower, because, the mash in the tun was held at 100F or close, for a longer time period. The lower pH of the 2nd decoction favors beta enzymes. The ideal mash pH should 5.2. Alpha optimum pH is 5.7, Beta optimum 4.7. pH 5.2 is in the center. Sauer malz or lactic is used to reduce mash pH. I use 2 pounds of sauer malz in a 25 pound grain bill for all tri-decoctions, using RO water adjusted.....If you experience no color change in the iodine test of the main mash after 45 minutes of resting at conv. temp., add a little more water. Then, check after a few minutes. You may have converted, but the mash thickness was too great and perhaps due to a crappy crush. The iodine turned black because you may have tested liquid pulled from starch loaded husk material. When you added the crushed malt did you add more water to the mash? A thick mash benefits the enzymes, but when it comes to conversion, it may need to be thinned a little. Keep at it, you'll get there after awhile. It will come from experience..

Thanks for the reply! That's a lot of info! lol. I'll break it down:

-That was indeed my first decoction mash. But I've done already 7 batches without any conversion problems.
-What do you mean by "he has excess, decocted mash left"? I used the Vdec = Vmash(Ttarget-Tstart)/(Tboil-Tstart) formula to calculate the volume of the decoction I would take from the main mash and added 20% more. Could that be wrong?
- The iodine stayed yellowish-brown after the conversion rest in both decoction, meaning there were no starches. That's how I how I had a full conversion in both of them. The same test in the main mash turned blueish-black.
- I use no control on pH. In fact, I don't even measure it. But, since both decoctions had a full conversion could that have been a problem? Now that you mentioned adding water, I added 1 quart of the sparge water to the main mash while in protein rest to raise the temp a little. Could that have been a problem too?
- I don't thing the crush was a problem. It was the same of the additional malt I added and the same I've been using in the other mashes.
-when I added the crushed malt, my suspicion was that I had more water than I should in the mash. I took some liquid from the mash and added 2 lbs of malt. Nothing changed so much. Then, I took some of the grains and added more 2 pounds and 1 quart of water. That was when the conversion happened.

Could that information I gave clarify the problem? Could the pH realy be the problem?

Thanks!

 

[VladOfTrub]

You may have pulled a little too much mash liquid with the decoctions. The pH thing serves two purposes, one is to beef up enzymes, the other is to reduce tannin extraction when boiling the mash. It's a good idea to check mash pH. The process shouldn't be started if the pH is above 6.2 or below 4.7. I have had the same thing occur, as you had happen. The times it happened were with very thick mash, 1 qt. per pound. The first time it happened, I freaked out. I was going to run it off and take a chance. After adding about 3 gallons of foundation water to the lautertun, I moved the mash to it. I stirred up the mash to let the bed settle. For sh!ts and grins, I did an iodine test and it was good. I didn't mash out, just ran it off with 170F water. If you run into the problem again, thin the mash, if that doesn't work add more crushed malt. I have never had the issue at 1.5 qt. lb. or greater. Regarding how much volume of mash to pull. The formula is horse shoes and hand grenades close. My idea of a thick mash, maybe way different than another brewers. I use one of those ice scoops that ice fisherman use. The mash liquid runs right through it. Then, I'll add mash liquid to the decoction kettle to thin it. If I have a thick mash in the tun, with little water above the mash. I'll add brewing water to the decoction kettle. My brewing and sparge water is generally pH 6.9. I keep track of the volume of added brewing water. The decoction mash pH stays in range with the brewing water addition. If you are going to get into decoction method brewing, it's a good idea to get a pH meter and a good electronic thermometer. Advice: Know what's in the brewing water. Stick with the same weight of grain and get to know from experience, how much mash you will need to pull to hit rest temps.. The 158F conv. temp., in the decoction kettle, isn't set in stone. For the 1st decoction go to 150, rest for 10 minutes then, jack the temp to 158 to conv.. The 2nd decoction go to 153 then to 158. Also, remember, the longer you spend fooling with the 2nd decoction, protein rest time will stretch out. If your hooked on a protein rest, switch to Weyermann Boh. light or dark, floor malt. Don't get discouraged if things don't come together. It takes time.