Micro malt house DIY for home malting automation

arzaman · 30/1/14

Hi
I’m an Italian homebrewer and after experimenting brewing and DIY and automation of my equipments in different direction I have started a new project that I would like to share

The idea is not new…producing a batch of beer from A to Z from the ground to the glass. I have alredy an hop garden and late autumn this year I have planted a small ground with 2 row barley that now is growing.

What I would like to share in order to get your comment and support is my idea of micro malt house: a small all in one drum malting system that could produce 5-6 kg of base malt.

I would like to perform steeping, germination and kilning in one single box with a good level of automation (via arduino microcontroller that I'’ using successfully for brewing and fermentation)

Here is the cad design of the structure

One square box with a rotating drum inside and a removable cover, a fan heater from one side and 2 fans on the top in order to create a heating flow. Two solenoid valve for water inlet and outlet and a gear motor for drum rotation.
The drum should be removable in order to load easily and clean the box

I’m a little bit warried about the max temperature I can achieve with this single box during kilning phase since all the component are not insulated like in a oven but I think that for base malt should be enough

The drum has been refurbished from a top loading washing machine

here is the fan with the 2Kw heating element

and the two way 12V solenoid valve and the level switch

about the motor I would like to use a stepper motor that I easier to control in term of rotation and steps but I don’t know if the torque is enough

I have provided the design and the specification to a local company specialized in stainless steel precision lase cut and that is the result for the mechanical part and structure

macca05 · 30/1/14

Wow man u r very clever. Keep the updates coming. Would love to see this working

Macca

arzaman · 30/1/14

thank you so much..
in order to see it working is a long journey ..

.but I will update at each significant step

any expeience in home malting process is appreciated

Davide

peas_and_corn · 30/1/14

What strain of barley are you growing? Not all of them are suited for malting

arzaman · 30/1/14

peas_and_corn said:
What strain of barley are you growing? Not all of them are suited for malting

you are absolutely right I'm growing specific 2 row barley for malting with low nitrogen

http://www.lg-italia.it/prodotti-2/32-cereali-a-paglia/orzi-maltari/59-concerto-orzo-distico

planted in late autumn

New_guy · 30/1/14

This is great!
I can't offer any advice sorry but enjoying watching your new kit come together

TheWiggman · 30/1/14

I haven't looked too hard, but I'm not aware of anyone who's made this concept of steeping and drying in the same box.
Very impressive, clearly a lot of thought's gone into it.

Stepper motors in my experience are very torquey. You've got a lot of reduction there so I'd be very surprised if it couldn't handle it.

One question - how do you drain all the liquid? It looks to come out a port in the side, which will leave a bed of water in the base. Would this water affect condition during drying?

indica86 · 30/1/14

Not For Horses · 30/1/14

Very very cool design!
How much malting have you done prior to this design?
As far as the kilning goes, if you're only doing base malt I would think that 85c with high air flow should be fairly easy for a stainless steel unit like yours.
Id be happy to help out with any questions you have about malting.

wobbly · 30/1/14

I know this is only half of the above system but this Youtube shows/details how someone used a second hand cloths dryer as there malting kiln Not as sophisticated as what is being proposed but it seemed to do the job. It also makes reference to another Youtube detailing how the barley was malted prior to roasting but I couldn't find/open it. Maybe you had to sign in or something

http://www.brewtoob.com/diy-malt-kiln/making-malt-at-home-malted-barley-the-malt-kiln-video_5e9c3d41c.html

Cheers

Wobbly

dibby33 · 30/1/14

:super:
Watching with interest.

hoppy2B · 31/1/14

If you don't mind me asking Davide, how much has this project cost you and how many hours have you put in?

Looks well designed by the way.

arzaman · 31/1/14

Wow a lot of interest overseas!

Some comments/answers
@TheWiggman Initially I had the idea to drain the water from the bottom and load from the top (or side wall) but than in order to make it simple I have selected a two way ball valve so I can have just one ¾” port
It is welded to the very bottom edge so I expect that almost all water will be drained ,
During the germination phase I think that some water could help to maintain the humidity
Before the killing phase maybe I can tilt a little bit the chassis and consider that I can always extract very easily the drum and use a drying cloth

@Not For Horses Your question is very appropriate…In all my project tipically I had a bottom up approach starting from experimenting the process , studying it very well , getting confidence with all phases an issue than moving to automation and equipment building. In the mal house I have used top down approach…just an idea and a concept and some theory of malting process…no practice..so any help and advice from experienced home malster is very appreciated.
The concern of high temperature is not related to the stainless steal box but to all the component attached..as a matter of fact motor, solenoid valve, fans, level switch etc..are all in contact with the structure and are not high temperature components. I will try to isolate with same silicon pad or ceramic screw but I’m still worried by the effect of heat

@wobbly spectacular…!

@hoppy2B very good question…also in other homebrewing project I got always this question..my standard answer is that is an hobby so I have no budget constrain, I have not to have my project approved by finance department..I do not have to perform any accounting.
Any way I’m off course keeping track of the expenses and compiling a BoM..many pieces are refurbished and the control part is very cheep ..my estimation is to stay below 400 Euro

thank you for the continuous stimulus
Davide

idzy · 31/1/14

About $600AUD not too bad

Camo6 · 31/1/14

That's a thing of beauty Davide. Looking forward to seeing how well it works.

You mention other homebrewing projects? You'd be doing us an injustice not to show us your other projects. Pretty please with sugar on top!

mr_wibble · 1/2/14

#1 I am not an expert. I've never malted grain, but I've read some books

I know a little about process control.
So...

From what I've read moisture level is an important process parameter in grain malting.

At the beginning you need to soak your grain, and keep it around a certain moisture level for germination (not too wet, not too dry). Perhaps using a humidity sensor (like https://core-electronics.com.au/store/index.php/am2315-encased-i2c-temperature-humidity-sensor.html ) would allow the system to measure the moisture content. An electronic valve (http://gryphonbrewing.com.au/product_info.php?products_id=633 ) could be used to control a mister / water sprinkler to increase the moisture level. I would guess that soon as water was turned on, the humidity reading would jump to 100% ?

The drying / roasting of the malted grain is moisture flow in the opposite direction. You want to (heat and) remove water, drying the malt to a predefined percentage of moisture content. Perhaps here as well you could measure the humidity of the exhaust air, and use this to guess/calculate the remaining moisture in the grain. Obviously this would need to work in conjunction with the kilning temperature, since all the different malts are kilned to higher temperatures (generally the darker the higher and thereby a lesser final moisture content).

Anyway, that's my initial thoughts.

cheers,
-kt

EDIT: Can't get that 2nd link to work - http://gryphonbrewing.com.au/product_info.php?products_id=633
EDIT2: Can't fix it. The forum software thinks a bracket before the http should be part of the URL during comment addition, but then recognises it as incorrect during display, and breaks the link. Re-editing doesn't seem to fix it.

Not For Horses · 1/2/14

Just to add to that, you will need to make sure you can control a few critical processes.
First up is the steeping and air rest cycle. I like to use a 24 hour steep followed by a 12 hour air rest followed by a 12 hour steep.
The grain will absorb about 40% of it's weight in water and will increase in volume as well. I haven't ever measured this increase but I would estimate it to be 25%.
The second thing to be careful with is the drying phase before kilning. I'd recommend 24 hours at 25-30c with high air flow. Lacto will thrive unless you have high air flow.

arzaman · 3/2/14

Mr Wibble said:
#1 I am not an expert. I've never malted grain, but I've read some books
I know a little about process control.
So...

From what I've read moisture level is an important process parameter in grain malting.

At the beginning you need to soak your grain, and keep it around a certain moisture level for germination (not too wet, not too dry).

I'm not sure what do you mean with "certain moisture level" during the soaking phase.

Reading some tutorial and books on the process and looking some video on youtube the grain during the soaking phase are completely submerged in the water than you have soaking period and air rest. I think it's not necessary to measure air humidity...the important variable to track is the grain humidity but a sensor for this is too expensive and difficult to manage. My idea is to control the soaking time..24-36 H and verify the humidity level weighting a well know sample of grain (100 seeds).

I still have a doubt in this phase If to continuously add water…I control the ball valve and I have level switch so I can fill the box up to the level switch. First question: how high should the level water be? Should completely dip the grain ?
then I expect that some water start to be absorbed and the total water level in some way could decrease. Should I compensate with new water? Should I keep always the water level up to the maximum?

During the germination phase if I understood well from theory a certain level of humidity should be keep , the important thing is to control the temperature since the germination produce heat.

My idea is to keep a small amount of water on the bottom of the box, below the level of the drum, and keep maybe the fan active (without heating) so creating a refreshing wet air flow. Controlling the humidity level could be quite complex and I don’t know how to adjust (fan speed ??)

Not For Horses said:
Just to add to that, you will need to make sure you can control a few critical processes.
First up is the steeping and air rest cycle. I like to use a 24 hour steep followed by a 12 hour air rest followed by a 12 hour steep.
The grain will absorb about 40% of it's weight in water and will increase in volume as well. I haven't ever measured this increase but I would estimate it to be 25%.
The second thing to be careful with is the drying phase before kilning. I'd recommend 24 hours at 25-30c with high air flow. Lacto will thrive unless you have high air flow.

How do you control th
e level of water absorbed by grains ? as stated before my idea is to weight a known number of seed (or even the whole drum since I can extract it)
What about humidity / temperature during the germination phase ?

ciao
Davide

Not For Horses · 3/2/14

You want the grain to absorb 40% of the starting weight in water. I have tried a number of different regimes and found that the soaking and air rest regime I have mentioned earlier to work best.
This requires complete immersion for the soaking and complete draining for the air rest.

The temperature during malting should be around 16c. Humidity I'm not sure about as I have never actually measured it.

You are correct about the heat during germination. The malt will heat up considerably if not turned regularly.

arzaman · 3/2/14

Not For Horses said:
This requires complete immersion for the soaking and complete draining for the air rest.

[SIZE=10.5pt]So I can proceed this way in the automation[/SIZE]

[SIZE=10.5pt]Insert the dry grain form the top load door in the drum[/SIZE]
[SIZE=10.5pt]Open inlet solenoid valve and fill the box with water. I will set the level switch close to the maximum level that is at the pivot drum level, this should completely submerge the grain[/SIZE]
[SIZE=10.5pt]Start rotating during the soaking period (any suggestion of speed?) in order to mix and oxygenate constantly the grain[/SIZE]
[SIZE=10.5pt]If the water level will decrease due to grain absorption (I don’t know if the total volume will be lower) or a little evaporation, compensate trough inlet solenoid valve: the water level in the box stay constant[/SIZE]
[SIZE=10.5pt]During the air rest period open the outlet solenoid valve and drain all the water[/SIZE]
[SIZE=10.5pt]Continue rotating the drum to aerate grains(suggested speed?)[/SIZE]
[SIZE=10.5pt]Repeat[/SIZE]

[SIZE=10.5pt]Davide[/SIZE]

Micro malt house DIY for home malting automation

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