User Manual

Last updated: Apil 16th, 2019

Table of Contents

  • Important Safety Information
  • Introduction
  • Setup
  • Malting with Acro
  • Care and Maintenance
  • Troubleshooting

Important Safety Information

  • Exercise common sense while operating Acro
  • Close supervision is needed when used around children.
  • Allow 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.
  • Make sure all ducts, tubes, and connections are in place before using Acro.
  • To avoid risk of electrical shock hazard do not disassemble Acro. There are no user serviceable parts inside.
  • 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.

Lightning Bolt




Acro Components

Please check to make sure you have all components before continuing. If any parts are missing contact Sprowt Labs immediately (

  1. Acro
  2. 6.5' Power cord
  3. Fuse (2) and Fuse Holder
  4. Duct Assembly
    1. 12" Duct
    2. Elbow
    3. During Steep & Air Rest:
      1. Bushing
      2. 1" Pipe Nipple, 4 1/2" long
      3. Motorized Ball Valve
      4. Tri Clover adapter
      5. False bottom gasket
    4. During Germ & Kiln:
      1. 1 1/2" Pipe Nipple, 8" long
      2. FPT – Tri Clover Adapter
      3. Silicon Tri Clover Gasket
  5. Plumbing fittings
    1. Male barb to Female NPT (3)
    2. Hose adapter
    3. Cap (2)
    4. Insulated tubing (2)
    5. Clamps (6)
    6. Inside vessel water-in extension assembly (tubing, filter fitting)
    7. Thread tape
  6. Drain Pan
  7. False bottom
  8. Leg extensions
  9. Temperature sensor


Acro Assembly

Visit the Acro Assembly page to learn more about how to assemble your new Acro.

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. The rubber feet should be threaded back in. Attach a duct assembly and rotate it into place to validate the final height. Downward pressure by the conical shouldn't be placed on the duct.

Replace the bolts in existing spike feet with included 8" bolts. Attach a duct assembly and rotate it into place to validate the height.


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. More on installing the fuse here

Wifi Setup
  1. Create your account on and Sign In.
  2. In the settings drop down menu in the upper rightmost corner navigate to 'Malthouse'.
  3. Click 'Add New Malthouse'.
  4. Follow the instructions provided.
Water Hookup

A water line needs to be hooked up to Acro for the duration of the steeping, air resting, and germinating steps.

Why? Acro automatically fills steeps, and can't fill the vessel if water is not hooked up. Additionally, 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.

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 damaged caused by high pressure will not be covered under warranty.

Water Flow Rate

It's very important to set your flow rate before you hook Acro up to water. Flow rates above 6 gpm (gallons/minute) will damage interior plumbing connections and cause water leaks or flooding.

Acro requires a flow rate between 3 - 5 gpm. To set this, we recommend turning your hose or faucet on and filling a vessel with a known volume of water while timing how long it takes to fill.

Malting with Acro

Recipes are designed in the web app on As we continue to build out our own documentation, we recommend referring to the included book on Home Malting for recipe design advice.

To start a batch from Acro:

  1. Go to Malting -> Select Recipe -> 'Your Recipe'
  2. Wash the grain before starting a steep. Go to Malting -> Wash Grain.
    1. Acro will fill the vessel up with water several inches above the grain. Stir the grain by hand or with a mash paddle to dislodge thins and chaff that will float to the surface. Use a sieve to collect this malting loss and compost it.
    2. Once you have removed all malting loss, go to Malting -> Vessel Drain.
    3. Repeat this fill/drain cycle 1-2 more times, until you can easily see the gran through the water, and no more malting loss if floating up.
  3. Go to Malting -> Start Batch. Steeping will begin.

You can also schedule a Batch on the Web application:

  1. Go to your App Dashboard (, and select a recipe that you want to run.
  2. On the recipe page, select "Start New Batch". This action will create a new batch page.
  3. Schedule a batch, by clicking "Set Start Time", setting and confirming the time that you'd like to start a batch. This is risk free. Delete our reschedule at any point.
  4. Once a batch is scheduled, you will get notifications as the batch approaches.
  5. When it is time to malt, you will need to start malting using the directions above.

Please refer to the malting overview reference document for more information on how to malt.

Care and Maintenance

Acro needs to be fully drained after a malting batch, and then cleaned.

To fully drain Acro, select Malting -> Acro Drain. Then pull out the drain pan, and remove the right drain cap.

Return the cap, and select Malting -> Clean Acro. Turn warm water on from your water hookup, and Acro will run a cleaning cycle. Afterwards, perform the same Acro Drain function.

Once water has been turned off, you can drain from the left drain cap, which drains the humidifier system.


Please contact the Sprowt Labs teams with any issues or bugs. We are committed to solving any problems, and appreciate your patience and support as we continuously refine and improve our product.