Stepped mash & decoction

[jonewer]

Hi All, A little help please.

I'm planning on doing a stepped mash with a decoction as roughly following this plan;

1. Add water to 6kg grain to bring to 40ish degrees for B-Glucanase
2. Raise to 65 for B-Amaylase
3. Drain off a few litres, boil 'em add them back, raise temp to 72 for A-Amylase

Main question is, how much water to add as the initial volume? I obviously dont want to add too much as I'll likely have to faff a bit adding hot and cold water to get the 65 so need room for manoeuvre, yet I dont want to add too little either, I presume 1l per kg will be too little?

I dunno. Help!

 

[Aleman]

:wha: Any particular reason you are doing a step/decoction mash??

I'm planning on doing a stepped mash with a decoction as roughly following this plan;

1. Add water to 6kg grain to bring to 40ish degrees for B-Glucanase
2. Raise to 65 for B-Amaylase
3. Drain off a few litres, boil 'em add them back, raise temp to 72 for A-Amylase

Main question is, how much water to add as the initial volume?

As much as it takes really . . If you use water just off the boil then it's surprising just how much you need to use. There are calculators out there that can tell you approximately how much hot liquor you will need, but I've not found then to be all that accurate.

If it was me, and I was using infusion stepped mashing, then I would use 2.5L /kg for the Glucan Mash, and add around 1L / Kg for the step to 65C.

HOWEVER Your temperatures are off for the enzyme rests!!!

The Glucan rest can be anywhere between 35-40C, I normally aim for 35C doing wheat beers.

Beta Amylase has an optimum of around 62C, but is functional from 60-66C (unfortunately proteases are also active at up to 64C so keep any time spent in this range shortish)

Alpha Amylase has an optimum of around 68C (again active from 64-72C)

At the upper ends of the temperature ranges the enzymes are destroyed faster so although conversion proceeds it may well take longer as there are fewer and fewer functional enzymes around to complete the conversion.

DO NOT take a thin (liquid) decoction for the alpha rest as boiling will destroy the alpha amylase (The enzymes are in the liquid not the grain at this stage of the mash).

You can take a thin decoction at the end for the alpha mash to stabilise the sugar balance and to achieve a mash out.

Here are some threads that explain things a little more clearly

Bohemian Pilsner
PJs Lager Lout
Alemans Effin Bohemian Pilsner
Dave Lines BBLTYB
Eroica for Czech Pils
Effin Bohemian Pilsner Brewday
Pilsner Help Required

 

[Darcey]

After rereading this my brain just exploded! :shock:

Back to the text books me things...