Decoction Frustrations

[motleybrew]

yesterday, I did my second decoction mash.during the mash I ran into the same problem I had the first time, bad temperature predictions. I followed the BeerSmith recommended amounts and I was unable to get the target temperature. I had to scramble to pull multiple smaller the decoctions in order to reach my final temperature. The plan was to do a protein rest with the mash and, pull a decoction and raise the temperature to 154 degrees and then a second time for mash out. was the first decoction I reached a temperature of 140 degrees. So my triple step process became a four step.

Does anyone have tips for how to pull decoctions properly? I have been scooping up cup fulls and using a strainer if necessary in order to ensure I pulled mostly just grain.

 

[ScottG58]

I pull more than the Beersmith estimate, add some, stir, check temp, add more if needed until I hit target. I use a quart ladle to skim grain.

 

[StoneHands]

I did my first decoction mash over the weekend (so that makes me an expert...) but managed to hit my temps pretty well. I used Kai's enhanced double decoction and pulled a little over half of the mash using a strainer and a small kitchen pot to pull the volume. It was nearly all of the grain. I mashed in at acid rest temps (about 100F), pulled the decoction, and slowly raised the decocted mash to 158 where I held it for about 40 minutes. Then I raised it to boiling, boiled for about 10 minutes, and then added part of it back to the main mash to get to protein rest at 130F while the rest of the pulled decoction still boiled. 10-15 mins later, I then wanted to get to 158 on the main but managed to get to 155 which was close enough for me. I think pulling extra and hitting the multiple rests with the single pull made it easier. I didn't do the second decoction mashout as I felt it unnecessary with a batch sparge.
Hit my volumes and gravities well, gravities were spot on actually (I expected a bump in efficiency, so I increased my water volumes a bit). Maybe I was lucky.

I think the key is to allow that conversion to happen in the decoction first before boiling, since you pull so much volume. This was 99% Munich malt too, so I was concerned about having enough enzymes for conversion after boiling too.

 

[StoneHands]

To add, my total mash volume at 1.75 qt/lb at acid rest dough in was just over 6 gallons (I used the markings on my cooler mash tun). I pulled just over 3 gallons of thick mash and put it in the pot, then added 2 quarts of additional water to this volume. It seemed like most of the grain, but it may not have been. I made sure the grain was covered in mash liquor, so it was thick but not "mounded grain" in the pot. It definitely thinned after conversion and boiling. Cool to do.

 

[motleybrew]

Interesting. I guess I should have read more about how the process works. I was pulling a calculated amount for each temp increase. With Kai's, you take it all and add back in increments. Ok....

 

[VladOfTrub]

Not hitting rest temperatures happens. Once you do a few more decoctions you'll get a feeling for how much mash you'll need to pull. The formulas to come up with how much mash to pull are close, but you may need to add some hot or cold water to hit the temp you're trying to achieve for the style of beer. You may want to consider pH before boiling the mash. My grain bill is usualy 27, 28 pounds. I pull 4 gallons of thick mash to go from acid rest temp 95F, to protein rest temp of about 128F. I use 2lbs of acid malt and pull the 1st decoction when the mash PH is 5.6. By the time I pull the 2nd decoction and add it back, the main mash pH is 5-5.1. That gives me a wort pH in the fermenter of 5.6. Lager yeast pH band. If you are using high modified malt, depending what type it is, each display a different pH level. Somewhere from 5.5-5.8 pH and that's it. If you use low modified malt, phytase will allow the pH to fall during the acid rest. Beta enzyme favors the slow reduction of mash pH. Where as alpha favors a higher pH. Sour malt helps lower pH after phytase is denatured during a higher temp protein rest with low kilned malt. The high kilning temp of high modified malt destroys phytase. That's why the malt will stick at a certain pH. Brew on. Keep at it, you'll get everything dialed in.

 

[BigEd]

yesterday, I did my second decoction mash.during the mash I ran into the same problem I had the first time, bad temperature predictions. I followed the BeerSmith recommended amounts and I was unable to get the target temperature. I had to scramble to pull multiple smaller the decoctions in order to reach my final temperature. The plan was to do a protein rest with the mash and, pull a decoction and raise the temperature to 154 degrees and then a second time for mash out. was the first decoction I reached a temperature of 140 degrees. So my triple step process became a four step.

Does anyone have tips for how to pull decoctions properly? I have been scooping up cup fulls and using a strainer if necessary in order to ensure I pulled mostly just grain.

Most if not all of the programs and many of the written instructions will result in a shortfall in temperature much like you encountered. While 1/3 of the mash is what you see most often you will probably get better results using 35-40%. Also think weight, not volume. It also makes the math simpler if you use a thick 1:1 water:grain ratio. At one quart to one pound you have essentially two pounds of water for every pound of grain. So ten pounds of grain and ten quarts of water give you a total mash weight of thirty pounds. That makes a 35% pull 10.5 pounds. Once you establish what your scooping implement of choice holds weighs just figure the total pull from that. Don't forget to strain before weighing so you get mostly wet grain and not too much liquid.

Starting with a quart of water in your decoction vessel helps prevent scorching and gives you more temperature insurance. If everything works as it's supposed to you should get a temperature rise of +20F once the decocted pull is added back to the main mash. It will take some practice but in time you will be able to do it easily.