Sprowt Labs Acro User manual

Acro the Personal Malthouse
User Manual
1 BBL

Acro the Personal Malthouse User Manual
V2.0 Last updated: November 1st, 2020
For the best user experience and access to important videos and additional information, please
access our online resources www.sprowtlabs.com/docs. The most up-to-date user agreement
is available at www.sprowtlabs.com/legal.
Table of Contents
Page 2: Important Safety Information
Page 2: Introduction
Page 3 - 4: Components
Page 4 - 7: Setup
Page 7: Controls Theory
Page 7 - 10: Electrical Panel Controls
Page 10 - 12: Malting with Acro
Page 13: Simple Base Malt Recipe
Page 13: Troubleshooting
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Important Safety Information
●Exercise common sense while operating Acro.
●Close supervision is needed when used around children.
●Allow the machine to fully cool before removing or replacing parts or grain.
●Do not operate with a frayed cord or broken plug.
●Only use with a GFCI circuit. Test the GFCI circuit before every use.
●Do not immerse or soak the machine in liquid.
●Make sure all ducts, tubes, and connections are in place before using Acro.
●To avoid risk of electrical shock hazard do not disassemble Acro.
●Various surfaces can get extremely hot or cold during the malting cycle, use caution
when coming into contact with the equipment or grain.
●Never insert fingers or hands inside Acro (duct, plumbing fixtures, electrical outlets).
●Do not operate with water pressure exceeding 50 PSI.
●Before kilning, always make sure the fogger is off, and there isn’t any water in the duct.
●When kilning, the fan must be on the entire time.
●During kilning, always turn the heater off and leave the fan on before powering Acro off
to let the heating element cool.
Introduction
Welcome to Home Malting! Sprowt Labs is a small company working to make beer’s
supply chain accessible to everyone. Malting is a complex process, and we’ve worked hard to
take out the frustrating labor, and leave you with the joys of developing new and unique malts,
and connecting with local agriculture.
We are constantly seeking out feedback and ways to better our equipment. If you have
any questions or ideas, please don’t hesitate to reach out to us at con[email protected]. You
may have purchased an Acro through a distributor or retailer, in which case we recommend you
still reach out directly to us for any equipment support. We will be better able to support you.
Cheers,
The Sprowt Labs Team
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Acro Components
Please check the included packing list to make sure you have all components before continuing.
If any parts are missing, please contact Sprowt Labs immediately ([e-mail]).
Shipment
Contents
Line Total
Box #1
Acro, the Personal Malthouse
1
Box #2
Spike Conical
1
Box #3
Acro Control Panel
1
Bag #1
Organic Malting Barley - USA Only
1
Box #4
Book, "Malting at Home"
1
Flexible Bucket
1
Grain Scoop
1
Grain Sieve
1
False Bottom
1
Drain Pan
1
Teflon Tape
1
Hose Flow Brass Valve
1
Hose to NPT Hex Swivel Brass Adapter
1
Hose Wye Fitting
1
1/2" NPT, SS Cap
1
Barb to 1/2" FPT, SS adapter
1
Grainbed Temperature Sensor
1
Power Cord
1
Fuse Cap
1
Fuses
2
Conical Tank Insulation Jacket
1
2" 90º SS Elbow
1
2" FPT to 2" Tri Clamp adapter
1
Main SS Duct With Insulation
1
Vessel Valve Assembly
1
3.5" SS NPT nipple
1
2" to 1" SS Reducer coupling
1
3

Lower Water Line Assembly (Filter Basket)
1
Upper Air Line Assembly (Tri Clamp)
1
Butterfly Hose Clamps
3
Germ/Kiln 2" SS Duct, Insulated
1
Female Camlock
2
SS Racking Arm
1
Manual Tri-clamp Drain Valve
1
2" Tri-clamp to 1/2" Barb
1
1/2" tube plug
1
1.5" Tri Clamp
4
1.5" Tri Clamp Gasket
4
Tri Clamp 1.5" Caps
3
2" Tri Clamp
2
2" Tri Clamp Gasket
2
2" Tri Clamp Gasket With Mesh
1
Spike Brewing Vessel Leg Extenders
4
Spike Brewing Vessel Feet
4
Spike Brewing Vessel Lid Gasket
1
~4' of 1/2" tubing
1
5' Tank-filling Hose
1
Hose Nozzle
1
Bolts for attaching Panel to Acro
4
Washers for attaching Panel to Acro
4
Rubber Vibration-Dampening Washers
4
Setup
Acro Location
Acro is on casters to make movement and location adjustment simpler. Choose a malting
location where Acro can have:
1. A dedicated 15-20 amp, 120V circuit with a GFCI outlet.
2. A water connection with below 50 psi pressure.
3. A water drain, either:
a. A floor drain, or
b. A drain you can empty containers of water into
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4. Indoor ambient conditions: 60-75F. You need ambient conditions that are warmer than
the germination temperatures you’re using, as Acro only cools (doesn’t heat) germinating
grain.
5. If you have high humidity, you may need a dehumidifier during kilning to shorten the
kilning process.
Acro has 2 air intake ports and 1 exhaust port. The intakes are on the front, lower left side of the
machine, and on the right (vessel) side. The exhaust is on the left (non vessel) side. Each of
these ports cannot be blocked, and must allow adequate airflow. Acro can be positioned near a
wall, but shouldn’t be pressed into a corner with inadequate airflow.
Attaching the Electrical Panel
The electrical control panel sits on top of Acro. The outlets on the left side of the panel align
with the plugs coming out of the port on the left side of Acro. There are 4 rivet nuts placed on
the top of the Acro skin, which align with 4 holes in the bottom of the electrical panel. A flathead
screwdriver is needed to open the electrical panel (after ensuring it is not plugged in or powered
on!), and 4 bolts and washers are provided, as well as an allen wrench, for attaching the panel to
Acro. Place the 4 vibration dampening rubber washers between Acro and the electrical panel.
After bolting Acro on, close and lock the panel.
Vessel Location and Connections
The vessel is positioned to the right of Acro, aligning with the duct hole, water drain hole, and
aeration hole. The vessel has leg extensions and adjustable feet to adjust to the correct height.
1. The 12” threaded pipe duct screws into Acro
2. A 90 degree elbow screws onto the end of the duct
3. During Steeping:
a. The vessel valve assembly attaches to the elbow.
4. During Germination and Kilning:
a. The shorter threaded pipe with tri clamp adapter attaches to the elbow.
Threads allow for height adjustment.
The 2 tubing lines connecting Acro and the Vessel:
1. Cam lock connections thread onto Acro.
2. The lower connection is the drain line that connects to the vessel valve. Water drains
through this line when steeps finish and the drain valve is opened.
3. The upper connection is the aeration line that connects the air pump to the vessel
connection on the side of the cone.
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Please visit www.sprowtlabs.com/docs for the Acro Assembly video and to learn more about
how to assemble your new Acro. Assembly videos are also available on the Sprowt Labs
youtube channel.
Vessel Heights
The vessel height doesn't need to be changed once set. The height is the same during steep/air
rest and germ/kiln, only the duct assembly is changed.
Leg extenders should be screwed into each leg, as well as rubber feet. Attach a duct assembly
and ball valve and rotate it into place to validate the final height. Downward pressure by the
conical shouldn't be placed on the duct. Use Acro’s caster wheels to easily move the malthouse
into position and validate the height.
Power
Acro must be run on a GFCI circuit. Connect the power cord from Acro's power receptacle to a
GFCI 120VAC standard wall outlet. DO NOT plug Acro in to an outlet until the fuse has been
installed.
Water Hookup
A water line needs to be hooked up to Acro for the duration of the air resting and germinating
steps. The provided wye and garden hose splits the water inlet before Acro, and allows for a line
to run to the top of the conical for washing and steep filling.
Constant water hookup is necessary to maintain the humidification system used during air rests
and germination.
You can use a standard hose or tubing to connect Acro to water. A 1/2" NPT male threaded
fitting on the water hookup allows you to connect either a female garden hose adapter or a
female thread to male barb adapter.
If you're using tubing instead of a hose, make sure to use tubing capable of handling your water
pressure. We use a tube with a 1/2" ID x 3/4" OD.
Preferably hook Acro up to a faucet with the ability to mix hot and cold water. In the winter, your
cold water might be below desired steeping temperatures, and Acro cannot heat water.
Water Pressure
Acro can handle water pressures up to 50 psi. Above this will damage interior plumbing
connections and cause water leaks or flooding. Plumbing damage caused by high pressure will
not be covered under warranty.
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Drain Pan
The drain pan slides under Acro, to catch condensation inside the machine. This will fill up
multiple times during the malting process. There is a hose fitting on the side to run to a floor
drain if available. Otherwise, this line can be plugged, and the user will need to empty the drain
pan regularly to prevent spills.
Controls Theory
Malting requires different climate controlled environments throughout the process. Acro
achieves these environments through the following ways:
● Submerged under water, with high dissolved oxygen levels
○ Air pump injects air into the steep water
● Cool and moist
○ An enclosed glycol loop runs across an air coil. The fan sucks air past this coil to
cool it down and runs it through an ultrasonic humidifier to humidify it. It then
blows this cool, moist air through the grain bed.
● Hot and dry
○ An electric heating element turns on and off, in conjunction with the fan, to blow
hot, dry air through the grain bed.
Electrical Panel Controls:
On/Off
A main on/off switch controls the panel and Acro. This switch is fused. Install the fuse before
the first time you plug Acro in.
Controllers Heater / Chiller / Fogger / Fan
3 controllers run across the top of the unit. These are labeled Heater, Chiller, and Fogger/Fan.
The Heater is a PID controller with Ramp/Soak controls (Auber SYL-2352P Model / user manual:
https://www.auberins.com/images/Manual/SYL-2352P%20Manual.pdf).
The Chiller and Fogger/Fan are PID controllers (Auber SYL-2352 Model / user manual:
https://www.auberins.com/images/Manual/SYL-2352_manual.pdf).
Each controller outputs:
1. A top temperature readout from a corresponding temperature sensor
2. A bottom temperature that is the set temperature the controller is working to maintain.
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There are 4 temperature sensors:
1. Duct Temperature: A sensor is positioned in the air duct, immediately after the heating
element. This temperature sensor is used to control the actuation of the heating
element. It is also used by the user in reading the duct temperature during cooling.
2. Chiller Temperature: A sensor is positioned inside the glycol plumbing loop, just after the
cooling coil. This temperature sensor is used to control the actuation of the chiller.
3. Grain Temperature: This is the only sensor you place in the grain bed. It is used to
actuate the fan and fogger when those components are switched to “controller,” and is
simply a temperature readout when those components are switched to “manual” or “off.”
a. The placement of the grain temperature sensor is important in running Acro.
i. Steep: The temperature sensor should be placed in the middle of the grain
bed to give an accurate representation of the steep temperature.
ii. Germination and Air Rest: The temperature sensor should be placed in the
top inch of the grain bed. Cooling and heating a grain bed happens
through segmentation over time: the bottom will be cold or hot well
before the top. If the temperature sensor is placed lower down in the grain
bed, cooling will stop before the top of the grain bed is cooled.
iii. Kilning: the temperature sensor is not used for control, and is only
representing the temperature of the location. If left near the top, it will
take a significant amount of time before the temperature at the top of the
bed matches the duct temperature / air-on temperature. Only once the
majority of water has been removed will the grain bed react more quickly
to the air on temperature.
4. There is a temperature readout in the top left corner of the flow sensor when it is turned
on. This temperature is from inside the electrical panel, and is for monitoring purposes.
Heat from the switch heatsinks raises the temperature inside the unit.
The controllers run different types of control models:
1. The Chiller controller is used to keep a glycol loop ready during germination and air rest,
which supplies cooled air to maintain grain temperature. The Chiller controller is placed
in “on/off” or “Bang-bang” control at shipment. When the sensed temperature is above
the set temperature, the chiller is turned on. Once it passes below the set temperature,
the chiller is turned off.
2. The Fan/Fogger controller is in the same “Bang-bang” control model as the chiller. The
user can run the fan and fogger manually to super-cool the grain bed if it becomes too
hot. Or the user can leave the fan and fogger in controller mode, and they will be turned
on and off when the grain bed is too hot or too cold. In addition, the Fan has a variable
speed controller to set fan speed. If this controller is set all the way to the left, it is turned
off, and the fan will not start when switched to manual or controller. The fan speed must
be turned past the first click to set a speed.
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3. The Heater controller is in PID mode, turning the heating element on and off for different
periods of time to maintain the duct temperature. The heater controller is also a
ramp/soak heater, which means it has 30 programmable steps of different times and
temperatures to program for your recipe. The heater can’t go above 356 degrees
Fahrenheit, as there is a safety thermostat inside of Acro that will turn the element off if
the duct gets above 356 degrees Fahrenheit.
The controllers are set in Celsius upon shipment, as the controllers can only use a decimal point
in Celsius. If the user requires Fahrenheit temperature without decimal point precision, please
refer to the above controller manual to update the settings.
Fan Speed
High fan speeds dry the grain out faster. Higher speeds also cool the grain faster. A balance
must be maintained during air rests and germination.
1. Low to medium speed should be used during air rests and germination. If the grain gets
too hot, short blasts at higher speeds can be used.
2. High speed should be used during kilning.
Timers Air Pump / Drain Valve
2 timers are used to automate malting steps. Your timer user manual is at the back of this
binder.
1. The air pump is run on a cycle timer in order to turn on and off during the steeping
process. The switch must also be turned on in order for the air pump to actuate once the
timer turns it on. Arrows are used on the timer to adjust the durations of the A or B
timers.
2. The drain valve is run on a cycle timer in order to start the steep drain. The switch must
be turned on for the valve to actuate when the timer ends.
Switches Vessel Valve / Chiller Pump
The vessel valve and chiller pump are both actuated directly by switch.
Flow Sensor
There is a flow sensor inside of the glycol loop, and the interior flow screen on the panel reads
this flow rate in liters per minute. You need to press Run/Stop to activate it, and again when you
turn the pump off.
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Glycol Loop
A standard chiller controller setting is 6 C/42 F, which generally lowers 20 C / 68 F ambient air
down to 12 C / 53 F cooling air. The unit is filled with polypropylene glycol, which freezes well
below water. However, for pump longevity, we don’t recommend running the chiller below 0 C /
32 F.
Malting with Acro
We recommend referring to the included book on Home Malting for recipe design advice.
Washing
1. The vessel is separated from Acro during washing. Attach the tri clamp manual butterfly
valve to the base of the conical, and the tri clamp to hose adapter to the end of the valve.
Depending on your grain, a lot of waste can flow out the bottom of the vessel, which can
quickly clog the drain filter line running into Acro. For an easier process, we recommend
draining the wash with the manual valve, and running your drain tubing to a sieve to
collect any waste sediment. You will fill the Vessel from the top with the included hose
after adding grain.
2. Weigh out your grain. You will lose some weight during malting, due to:
1. Moisture loss: Your starting grain is around 12% moisture, and will complete
kilning around 4%.
2. Respiration: weight is lost through co2 production.
3. Washing waste: chaff, immature kernels, etc. are washed out at the start.
4. Culms: dried rootlets are removed after malting.
3. If you don’t have a method for moisture analysis, take a small sample (~5 grams) to
track moisture content and keep it in a mesh bag or tea ball.
4. Place the false bottom in the conical, and your weighed out grain on top of it.
1. Ensuring your false bottom is level is important in having distributed aeration
when the air pump turns on.
2. Although you can run steeps and air rests in the cone, you will have reduced air
flow through the restricting vessel valve. This can work for smaller batches, and
use less water. In this case, you’ll dump the grain out the bottom of the cone after
you complete your steep/air rest rotation, and move it onto the false bottom for
germination and kiln.
5. Wash the grain before starting a steep. Immature kernels, chaff, and other waste will
float up and out of the grain bed. Stir the grain by hand or with a mash paddle to dislodge
thins and chaff (malting loss) that will float to the surface. Use a sieve to collect this
malting loss and compost it.
6. Repeat this fill/drain cycle 1-2 more times, until you can easily see the grain through the
water, and no more malting loss is floating up.
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Steeping
1. Your washed grain is on the false bottom.
2. Fill the vessel with water from the hose. Aim for around 3 inches of water above the
grain bed.
3. Place your probe in the grain bed to observe water temperature on the grain temp
controller.
4. Edit your air pump timer to your desired on/off durations. We recommend starting with
15 minutes on, 15 minutes off. Turn the air pump switch on.
5. Edit your drain valve timer to your desired steep duration. Turn your drain valve on.
Air Rests
1. When your steep is fully drained, turn on your vessel valve to allow air flow to move
through the grain bed to maintain temperature and remove CO2 build up.
2. Turn on your chiller pump to start moving the glycol loop.
3. Turn on your flow sensor panel to make sure the chiller pump flow rate is running. This
flow rate adjusts with temperature. It starts higher (around 3-5 lpm), and will go down as
the temperature cools (around 1-3 lpm). If your flow rate is stopped, you either have set
your chiller too low, or have air in the system, preventing the pump from running.
4. Turn the chiller switch on, which will allow the chiller controller to start cooling the glycol
loop.
5. Turn your fogger and fan switches to the controller setting, allowing the fog/fan
controller to run and maintain temperature during the air rest.
6. Give the grain a stir, and check the moisture content.
Steep/Air Rest Repeats
1. Follow your recipe, repeating steep and air rest sections until you have achieved your
desired moisture content.
Germination
1. Once steeping is completed, you can remove the vessel valve, and replace it with the
threaded pipe. We no longer have water in the vessel, and can have higher air flows with
the new duct.
2. Your grain should be “chitting” with small white rootlets appearing. It’s now time to keep
the grain cool and moist until it is modified.
3. Controls are the same as air rest:
a. Turn on you chiller pump
b. Ensure you have a good flow rate
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c. Turn on the chiller switch, enabling the chiller controller
d. Turn the fan/fogger switches to the controller setting, allowing temperature
control of the grain bed.
4. Turn the grain regularly to prevent rootlet clumps from forming.
5. If the grain is drying out too much, you can spray additional water onto it.
6. Refer to other available resources on kernel modification and evaluating the germination
process.
Kilning
1. Once your grain is modified, it’s time to kiln.
2. Turn off all components.
3. Detach the duct from the vessel, and tip it over to drain any condensation from inside the
duct.
4. Reattach the duct, and turn the fan to manual and full speed.
5. Run the fan for a minute to dry out the interior duct and ensure there isn’t any moisture
on the heating element.
6. Program your heater controller ramp/soak schedule.
7. Turn the heater switch on.
8. Check on your grain regularly to observe the drying process:
a. Sections of grain will dry from the bottom up, and the temperature at the top of
the grain bed won’t increase until a significant amount of moisture has been
removed from the grain.
9. When your cycle has completed, turn the heater off, and run the fan until your grain has
cooled down.
10. Detach the duct, place the flexible bucket under the vessel, and agitate the grain bed
vigorously to remove the culms (dried rootlets) from the grain.
1 BBL Note: With larger batch sizes used in the 1 BBL version of the Acro, drying times are
extended. Instead of 24 hours to dry a smaller batch, it can take up to 48 hours for drying.
Removing all of the water from a larger batch is also impacted more by the ambient conditions.
Drier ambient air will speed up the drying process. Running a dehumidifier nearby the air intake
vent on the Acro can assist in drying times. Additionally, turning the grain can assist in the
drying process with larger batches. Humid ambient conditions and long drying times with no
turning can lead to mold growth at the top of the batch before kilning is complete.
Please refer to the malting overview reference document for more information on how to malt.
This document is available at www.sprowtlabs.com/docs.
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Simple Base Malt Recipe
For a 15 lb batch, start with 19 lbs of malting barley with a high germination rate.
Steep to 45% moisture:
● Steep 1: 8 hrs, 58F/14.4C
● Air Rest 1: 12 hrs, 60F/15.5C
● Steep 2: 8 hrs, 58F/14.4C
● Air Rest 2: 9 hrs, 60F/15.5C
● Steep 3: 4 hrs, 58F/14.4C
Germinate for 4 days at 62F/16.6C
Kilning:
● 8 hrs at 110F/43.3C
● 8 hrs at 125F/51.6C
● 6.5 hrs at 150F/65.5C
● 2.5 hrs at 180F/82.2C
Troubleshooting
Please contact the Sprowt Labs teams with any issues. We are committed to solving any
problems, and appreciate your patience and support as we continuously refine and improve our
product. You can reach us in the following ways:
Email: [email protected]
Website: www.sprowtlabs.com/contact
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