I have been experimenting with the opportunity to do a high gravity brew with my 20 litre BM and this is what I did today to achieve a reasonable result.
Dicko’s Method
On my BM with my efficiency I find that a 1.075 og beer will need 7.7 kg of grain
This recipe has 0.750kg of crystal.
If I had have steeped the crystals in my recipe separately I would have achieved a
1.081 beer from the mash tun with the same volume of grain and just added the steeping from the crystal to the boil.
The basic theory behind my procedure below is that once the sugars are partially washed from the grain husks and are suspended in the water to form wort, then the volume of the grain in the mash is less by that amount of sugars.
Your personal figures will vary with the mash efficiencies within your system.
Weigh and crush the grain keeping the crystal and the balance of the base malt in a separate container which represents the difference between 5 kg and the total grain needed.
Measure your water to the 25 litre mark and then subtract the amount that represents the extra grain absorption above 6kg.
In my case this is 1.7kg x 0.66litre = 1.12litres.
So you will have approx 24 litres of water in the kettle for the mash. Add the extra water to the sparge amount.
I feel I could bring this volume down even further to around 23 litres and sparge the extra litre.
Bring the BM to dough in temp…I use 38deg.
Tip 5kg of crushed base grain into the malt pipe as per normal and mix thoroughly.
Lift the malt pipe onto the bottom pegs on the malt pipe and support it on the BM stirrup.
DO NOT lift the malt pipe completely out of the kettle as you will then introduce crushed grains into the wort through the bottom centre hole in the screen.
Insert the top plate and gently push the mash down the malt pipe…I gained 150mm of depth in the pipe.
Drop the malt pipe back into position slowly as it will take a little while for the wort to rise up through the grain again. I found by leaving the top screen on it saved any grain coming over the top.
Add the rest of the grain which in my case was 2.7kg of grain to the top of the malt pipe. Add only small amount and stir well as you go.
When the grain is in and wet then place the top screen back on and gently compress the grain so that you can install the cross bar and wing nut.
I need to add that I have a rubber seal on my top screen and this prevented any grain from escaping. This is something that may need to be watched if you are “riding bareback” without the rubber.
:lol:
Now just start your program from the dough in as you normally would.
I have noticed as the mash becomes hotter the flow increases through the malt pipe. Although it is slower than normal I would assume this happens anyway in any mash size.
I might add at this stage that I would not advise a full volume mash with this method as I feel it would come very close to overflowing the kettle. This would be up to the courage and daring of the operator
:lol:
I have lifted the top plate and stirred the mash at the middle of each mash step except for mash out when I stirred it at the beginning of the step as I wanted to achieve a clear wort.
I must point out that the grain bed was fairly solid and actually rather than stir I pushed a piece of stainless flat bar about 2.5mm thick and about 25 mm wide from the top of the bed to the bottom. You could use a large knife or similar for this process.
I did this stirring or stabbing because I was doubtful of good extraction but I can’t tell now as I got to my pre boil gravity as predicted. VERY HAPPY.
I will have to try another mash without stirring to find out.
I also stabbed the grain bed for the sparge as I found it was fairly slow and I was getting impatient.
Here is my recipe
Dicko’s Doppelbock
Pre Boil Gravity 1.062
Post Boil OG 1.075
Predicted FG 1.015.
Batch Size 25l in kettle after cooling
IBU 23.9 calculated No Chill at 27
Grain
68.6% Vienna
21.8% Pilsener
9% Caramunich
0.6% Carafa 2
Mash
Dough in 38 deg
10 mins at 40 deg
10 mins at 50 deg
60 mins at 60 deg
20 mins at 70 deg
20 mins at 77 deg
Hops
44gr of Spalt 5.2%aa at 60 mins
32gr of Hallatau Mittlefrau 3.0%aa at 10 mins (no chill)
Yeast
63gr of S189. coz that’s the only lager yeast I have at the moment.
Water
Total water (ppm):
Ca: 128 / 128
Mg: 11 / 11
Na: 0 / 0
Cl: 69 / 69
SO4: 124 / 124
Cl to SO4 Ratio: 0.55 / 0.55
Alkalinity (CaCO3): 70
RA: -28
Estimated pH: 5.42
Added the chalk only to the mash.
And here are some pictures.
Not a bad result out of a 20 litre BM