Need help - Decoction Mash

[dionbill]

So, I recently built and electric 20 gal all grain system and this weekend was to be my first AG through it. My neighbor decides that he will buy the 10 gal kit as he has drank a lot of my beer in the past. Knowing nothing about the brewing process, he goes out and gets a Dinkle Dunkleweizen, which is a decoction mash, which I have never done, or even heard of at that point. Below are the instructions and the part that is getting me, that I'm hoping to get some advice on is the decoction of 3 qt. Once I add the 2.7 qt of boiling water and wait 30 min, then I pull the 3 qt. of mash. It says to heat to 155 and wait for conversion - how long will that take exactly??? And when I'm doing this whole decoction process, do I just leave the main mash as is. The temp of that will drop because I built a HERMS system meant for cycling the wort. ORA, should I just ignore that and do a multiple step mash infusion. Any help or advice anyone can give would be great! Thanks..

Decoction mash. Mash in with 15.5 qt at 150 degrees to acheive protein rest at 135 for 15 minutes. Infuse 2.7 qt boiling water for rest at 145 for 30 minutes. Immediately draw off a thick decoction of 3 qt of the mash. Raise decoction to 155 and allow conversion. Once conversion is complete, boil decoction and add back to main mash to reach 155 for 60 minutes. Infuse 7.5 qt boiling water to mashout at 170 for 10 minutes. Sparge. Boil for 75 minutes adding 1.5 oz. Hallertauer when the boil starts. Add .5 oz. Hallertauer with 30 minutes remaining. Cool, pitch yeast and ferment.

Dion


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[bikesandbrews]

when i convert my decoctions i start a 10 minute timer as soon as the decoction passes 140f and then another timer as soon as i boil breaks.

does it suggest boiling the decoction for a period of time? in my experience there should be a length of time the decoction is boiled for, especially during the conversion rest.

 

[dionbill]

It doesn't suggest a boil time for the decoction. That's all the instructions it came with. How long do you suggest i boil for? The final boil is 75 min. When your decoction hits 140F and you start the timer, do you continue heating it or do you leave it at 140F for 10min, then heat to boil? Thanks for the help with this.

Dion

 

[VladOfTrub]

The instruction say that the main mash has to rest at 145F for 30 minutes. So, from the time when the 3 quart decoction is pulled, converted and boiled, has to happen within the 30 minute rest period. That's why the instructions direct the brewer to "immediately pull the mash." But, then comes the dilemma; the instructions say to allow the decoction to fully convert. It's kind of a Catch-22.

Since, you have never boiled 3 quarts of thick mash before. You have no idea how long it is going to take to raise the temperature of the decoction from 145F to 155F and then to boiling. It is hard to determine how long the conversion rest will be, without knowing what your brewing system can do with three quarts of thick mash within 30 minutes.

You can; raise the temp as quick as possible in the decoction to 155F. Rest at 155F for 20 minutes. Then reach boiling and boil for 10 minutes. Shorten the alpha rest to 30 minutes. Use iodine to check for conversion.

Mash in the decoction darkens when it converts. When mash is boiled for a time period, it will become darker at the time Malliard reaction occurs. After Malliard reaction, comes Melanoidin.

The first decoction can be played around with more, if it is pulled during the acid rest. Enzymatic activity is slow during the acid rest. When the decoction is pulled during the beta rest, the enzyme time clock starts ticking.

When mash is boiled, hard starch will burst. When this occurs, amylopectin is released. That's what causes mash to gelatinize. During the 145F beta rest, amylopectin will convert. Also, B-limit dextrins will be produced.

Before boiling the first decoction, ensure that mash pH is at least 5.8. Tannin extraction can occur if mash pH is above 5.8. When the first decoction has been pulled, lower the pH of the mash remaining in the tun to 5.3. Use some sour malt if you're following the German Purity Code.

Good luck.....Brew on....

 

[schiersteinbrewing]

This video may help you. http://brewingtv.com/episodes/2011/3/29/brewing-tv-episode-34-decoction-day.html

It's what i use for my first decoction mash and it went flawlessly and made and excellent Oktoberfest.

 

[VladOfTrub]

schierstein,

Since, you brewed beer by following the vid. How long was the protein rest when you brewed?

In the vid, he pulled the 2nd decoction after resting the main mash for 20 minutes at beta temperature. When you brewed, how long was the entire beta rest?

There's a glitch in the vid. The guy doesn't mention how long the protein rest lasted.
Adding up the time it takes for 19 quarts of mash to go from 122F, through conversion, to the time it takes to reach Malliard reaction and the formation of Melanoidin; adds up to an over extended protein rest for high modified malt.

I tri-decoction and use low modified malt. When I brew Oktoberfest, I usually brew it in late winter, early spring and age it until October. I start out by doughing in at an acid rest temperature and pull the 1st decoction at that temperature. Enzymatic activity in the main mash is at the lowest during the acid rest. This allows me to have more time to work with the 1st decoction. Also, I rest the 1st decoction at 122F for 15 minutes, before raising the temperature to 155F. I choose 155F, because mash pH usually drops to 5.8/5.6 during the acid rest. The pH is close to optimum for alpha, at 155F. I use the 1st decoction to raise the main mash temperature to 135F.

Sounds like you did a great job on your brew.

 

[schiersteinbrewing]

I use todays high modified malts and a double decoction. Protein rest at 120 for 20 min (very thick mash), then heat the entire mash to 140 (with boiling water), then pull 1st decoction, then add decoction back to mash until it reaches 155, rest 20 min, pull 2nd decoction, then add decoction back to mash until it reaches 168, rest 15 min.

Each decoction is 1qt thick mash for every lb of grain, brought to boil, then simmered for 15 min. I use a 1qt ladle I bought from a restaurant supply.

I heat the entire mash to 140 because I have read that if your protein rest goes too long, you break down the proteins too much and your head retention suffers.

Makes for a long messy brew day, but the end result is simply amazing beer.

This was another site I used to learn about decoction mashing http://braukaiser.com/wiki/index.php?title=Decoction_Mashing. At the the end of the article there are links to a 3 part youtube series on what is covered in the article, and a decoction brew day.

 

[VladOfTrub]

"the end result is simply amazing beer"

That's what it's all about.
I began to learn about the decoction method in 1987 and stuck with it for that reason.

"I heat the entire mash to 140 because I have read that if your protein rest goes too long, you break down the proteins too much and your head retention suffers."

Protein rest temperature and rest period are determined by the Kolbach number. That's when the data sheet for the malt being used comes in handy.

In the process you are using.
When you chose 140F as a conversion temperature, the mash was resting in the proteolytic range. During that time, beta glucan is being converted to glucose and the mash viscosity reduces. All of that is good.
But, here's a not so good part. Beta is working very slowly. Limited formation of maltose and maltriose occurs. There should be a temperature step added, the temperature should be optimum for beta. Mash pH should be close to optimum for beta, if it isn't, adjustments will be needed.
When the 1st decoction was boiled, amylopectin was released and the mash gelatinized. The jelled decoction was added back into the main mash to reach 155F. The next thing that happens is, alpha begins to slowly liquify and convert the jelled mash into non-fermentable sugar and A-limit dextrin. All of that is good.
But, again, the not so good part. Since, beta thermally denatures quickly at 155F, limited production of maltose, maltriose and B-limit dextrin occurs. Maltriose is the fuel for yeast during the lagering phase.
The next step in your process involves boiling the 2nd decoction. Once again, the mash jelled up when it was boiled. The problem with this is, the jelled decoction is being used to reach a temperature that will rapidly, denature enzymes. Chance are, enzymatic action was curtailed before the jelled mash was fully converted. If Iodine is used, it will turn dark red/mahogany. Usually, the thinnest part of the mash is removed and boiled during the final decoction. It is removed when 10 minutes remain before conversion.
The brewer in the Chip & Dale vid added the jelled decoctions back into the main mash for conversion during the 148F beta and 158F alpha-I rest. By doing it that way, he was ensuring that jelled mash wouldn't be carried over to the lautertun. Also, he converted both decoctions before boiling them.

Learning about how and why enzymes work and learning about the roles they play in brewing, can make a "simply amazing beer," even more amazing.