Decoction amounts for a bohemian pilsner

[firebird400]

Hello.
I have been brewing all-grain since 2009 and have tried just about everything in the game with different success through out the years.

I have two temp controlled chest freezers for fermentation and lagering and loads of other brewing related gismos.

My brewing set-up is a lot different than must use. I have a home made computer controlled recirculated electric set-up with a giant stir-bar that tumbles the grain during mashing. This gives me efficiency of 90% every time.

This works great for just about everything I want to brew, other than styles that benefit from being decocted there is.
I could shut down the system and pull some grains from the mash to do a decotion but I worry that it could cause a blockage and ruin the whole thing.

What I want to do is pre-boil a portion of the grain bill to get the benefits of a decoction, mostly the added color but also all the other things a decotion gives. (not that I know for sure what that is)
I know that the grains I am using are very well modified and a dection is not needed but I want to include it.
So the question is, how much of the grain bill should be pre-boiled
I also know that a grain bill of mostly pilsner malt will not give me the 4 SRM color I am after.
I will include some Munich malt as well as CaraPils and acidulated malt, even some CaraMunich malt. I have not nailed down the grain bill yet. Adding some meanoidin malt will also darken the wort during the 90 min boil but I am not a fan of melanoidin malt. I find that it can be a bit over powering.

My local water is high in chloride so I have spent days making over 20 gal. of distilled water to build my own water. I make 15.5 gal batches.
So I have a lot invested in this.
I will also be making a giant starter from fresh WYeast Urquell yeast and controlling the fermentation and lagering temps, even for the starter.

Now I am no expert. Specially when it comes to making lagers. So if you find a fault to this plan of mine please feel free to throw some critique my way as well as some advice.

Thank you
Firebird400 from Iceland

 

[didinho]

Hello.
So the question is, how much of the grain bill should be pre-boiled

usually I boil the 30% of the mash (water + grains), but while the mash already started: so enzymes already converted a part of the the starch, and are mainly in the water part of the mash. then, when you boil 30% of the mash, there are also sugars that undergo some maillard reactions, giving the caramellized/malty taste to decoction beers, and I'm not sure is the same if you boil unconverted grains (there are no sugars but just starch).
so, maybe you can start the mash with 70% of the grains at beta-amilase temps. in the meanwhile mash at 72°C the 30% of the grains for 20 minutes, then boil it for 20' more and add to the rest of the mash.

congratulations for your beer equipment!

 

[firebird400]

Thank you

We have made some changes and improvements to it since this picture was taken, mounted to the control box to the cart for example.
Mashing, boiling and cooling are done in this one unit. It holds about 33 lbs of grain.

You make a good point about the grain being totally unconverted and the maillard reaction.

I have since I posted this post read more on decoction, grain quality and other things that effect a Bohemian pilsner more that perhaps other styles. I may just add some melanoidin malt and even unmalted/flaked barley in the grain bill

 

[cantrell00]

1 qt per lb of mash grist. Add what you need to hit the next rest. Once the rest cools, add it too.

Rinse repeat. This method allows you to decoct a large % of the grist.

 

[firebird400]

I usually do not add any water to the mash during the mashing process. I start with all the water, other that the sparge water and adjust the temp via PID controller.
The system has two 2000 watt heating elements in it. It also has a built in cooling spiral so I can ramp up and down during the brew process all I want.
Adding a near boiling decoction to the mash would mess things up. Not to mention having to stop it, that is surely going to cause things to get stuck. This is the first real down side to my system
That is why I am trying to figure out another way to do it.

 

[cantrell00]

I usually do not add any water to the mash during the mashing process. I start with all the water, other that the sparge water and adjust the temp via PID controller.
The system has two 2000 watt heating elements in it. It also has a built in cooling spiral so I can ramp up and down during the brew process all I want.
Adding a near boiling decoction to the mash would mess things up. Not to mention having to stop it, that is surely going to cause things to get stuck. This is the first real down side to my system
That is why I am trying to figure out another way to do it.

I've done decoctions with assistance from my HERMS several times. I just stop the pump while pulling the grist and then turn it back on.

Same thing when adding it back.

Makes it easier actually because the HERMS guarantees you hit the next mash rest exactly where intended.