DECOCTION DE-MYSTIFIED
Decoction and Mashing. The two words will always come up at some time or another, but no more so when you hear conversations or read articles that cover German and Eastern European brewing.
When craftbrewers venture into all-grain brewing, its no accident that nearly all start with INFUSION mashing. And why not! It’s a simple process that most commercial breweries still perform to this day. Its easy and gives great results.
BUT, sooner or later the craftbrewer will hear about the process of decoction mashing, and wonder if its any good, or if its worth the effort. Further, they will hear about the process, and how to do it, yet after reading and researching about it, will still be left wondering how to do it. Why, because no-one actually gives any pictures explaining the process.
Now there is an on going debate about the benefits of decoction mashing. But this article will not cover the pros and cons of decoction mashing, if it works or not. That’s something for the craftbrewer to decide. This article is a quick picture process of a decoction. If you like, breaking down all those long winded explanations into a simple easy process. To help you I have included pictures of my setup, and you can click on each one to show a full size image.
NOTE. It is assumed
that anyone reading this will have an understanding of mashing, temperature
rests, and the equipment that is used. Decoction mashing should only
be practiced by someone who is comfortable with the mashing process.
DOUBLE DECOCTION / MY SETUP
The process you are going to see is a double decoction. This was part of a brew day I did recently for a German Pilsner. A decoction is simply taking a small amount of grain, cooking it and returning it back to the main mash. A double decoction is doing the process twice.
To give you an idea
of volumes in these pictures you need some background information. The
brew size is 38 Litres. The grain bill is 6.8kg of imported Pilsner malt,
with 200grams of Cara-Vienna grain and 500grams of white rice. My mash
tun is a 50 litre stainless steel beer keg, and the pots pictured are
20 litre capacity.
BE PREPARED
Organization is the key to an easy decoction. All your gear should be at hand and setout in easy reach BEFORE you start.
In this photo I’m ready to start. On the bench you can see the pot on the burner. Behind it is the thermometer and lid. You can see the rice I am going to use in the recipe, crushed and ready to go. The wooden handle sticking out of the partial visible keg is my spoon, while the partial hidden keg is my mash tun.
As you can see, everything is close by each other and in easy reach.
OK lets get started!
ADJUNCT BOILING
Add your water and
MALTED grain to your mash tun. Any raw grain should not be added at this
stage. It should be broken down to ensure that the starch is released.
In my case the grain is rice. This is done by cooking it. A very important
point to remember is to stir regularly, or you will get burning. Grain
is very prone to this. Once you start heating up any grain, make sure
you constantly stir it.
FIRST DECOCTION
Here you add the grain from the mash tun. Now the aim here is to add mostly grain. The liquid you must leave behind, but still have enough to stop burning.
You can use anything
to lift the grain out of the mash tun. Here I use a small pot. As I lift
it out I squeeze out as much moisture as I can. Then add this to the pot
and keep doing such until you transfer about 40% of the grain.
The question of course will be how much is 40 %. Well that’s a guess,
but for my system its about as full as the picture of the pot below. Its
is not critical to be exact, as there is a good margin of error.
Now note a number of
things in this photo. Firstly the level of grain. The pot is about 2/3
fill. Also note that there is only a small amount of liquid. There is
enough to stop burning but that’s it. Finally note the colour of the grain.
Very light!
Now immediately bring this to 70C as quickly as possible to allow for starch conversion. Stir continuously and when at 70C turn off the heat and put the lid on. Leave for half an hour then bring the pot to the boil. Boil for 15 minutes.
You will notice an immediate change to the grain as the pot nears boiling. The grain will thin out and you will not have to stir the grain as much. In fact once its near boiling you only need to stir the grain occasionally.
RETURNING FIRST DECOCTION
After 15 minutes boiling the grain you return it to the mash tun. This will raise the temperature of the mash to the protein rest.
I use my pot again
and quickly transfer the grain. Now most importantly note two things.
The first is the colour. Decoction mashing will very slightly darken your grain. The returned grain is darker, but that’s good. It’s the actual evidence of the additional flavours you have made. In fact the cooking adds flavours that you can actually see.
The second important think to note is the returned decoction is very runny. This is the evidence of the increased efficiency they talk about with decoction mashing. All available starch and sugar have been broken down and put into solution by the first boil.
Now the temperature
of the mash tun will naturally rise, and in this case will hit about 50C,
give or take. That’s fine. This of course is the protein rest. This is
the first decoction finished. You now let the mash rest for as long as
you wish, depending on the type of grain you are using.
SECOND DECOCTION
This is an exact mirror image of the first decoction.
Note again it’s a similar
amount (volume) of grain. Also note there’s a little more liquid this
time. This is because the mash is runnier after the first decoction and
protein rest so it’s harder to get just the grain and squeeze out all
the liquid. Still try to get as much grain as you can. Again follow the
first decoction procedures and return this to the mash tun. If you are
lucky you will hit your final temperature for scarification.
POINTS TO REMEMBER
Decoction mashing is not hard but there are points to remember
- ORGANISE - It will add easily an extra few hours to a brew day. Good
organization will keep that to a minimum
- STIR – Grain will burn if not stirred when you heat it up. Constant
stirring is a must until it boils, then you can rest
- LIFT ABOUT 40% - Don’t worry about getting it exactly 40%. There
is room for error.
- DON’T PANIC – If the temperature is not spot on add some water. A
lot of conversion has already occurred in the pot before hand.
- DON’T GIVE UP – Don’t be surprised if you first attempt is a disaster. Like anything, practice makes perfect. Most brewers get the proportions right by the second of third attempt at it.
Shout
Graham Sanders